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A Amphere.

A Asbestos insulated, no braid, for dry locations only. In raceways, only for leads to or within apparatus. Limited to 300V, 200°C.

AA Asbestos insulated, asbestos or glass braid. Open wiring in dry locations only. In raceways, only for leads to or within apparatus. Limited to 300V, 200°C.

AB High-voltage butyl cable.

ABC Armored bushed cable. BX-armored building wire with polyvinyl chloride insulation, 600V.

ABP Butyl-polyethlene high voltage cable, 75°C.

Abrasion Resistance Ability of material or cable to resist surface wear.

ABS Acrylonitrile butadiene styrene.

AC (See Armored Cable)

AC Alternating current.

ACA Synthetic tapes, felted asbestos, glazed cotton or glass braid. 1,000V, 90°C.

Accelerated Aging A test performed on material or cable meant to duplicate long time environmental conditions in a relatively short space of time.

Accelerator A chemical additive that hastens the chemical reaction under specific conditions.

Acceptance Test Made to demonstrate the degree of compliance with specificied requirements.

ACR Corona-resisting insulation.

ACSR Steel reinforced aluminum cable.

ACT Armored cable containing plastic insulated conductors.

Activator A chemical additive used to initiate the chemical reaction in a specific chemical mixture.

ACU Armored cable containing latex rubber insulated conductors.

ACV Armored cable containing varnished-cambric insulated, polyvinyl chloride covered conductors. 5,000V.

Adjacent Conductor Conductor next to another conductor either in the same multi-conductor cable layer or in adjacent layers.

Administrative Authority or AHJ An organization exercising jurisdiction over the National Electrical Code.

Admittance The reciprocal of impedance. Referred to as Mho or Siemens.

AEIC Association of Edison Illuminated Companies.

Aerial Cable Pre- or field assembled grouping of insulated conductors lashed or attached to messenger. Suitable for environment and supported in air by the messenger.

AF Asbestos insulated, single solid or stranded conductor fixture wire. Impregnated with moisture-resisting, flame-retarding compound. With or without braid. 300V, 150ºC.

AF Audio frequency.

AFC Two or three individually braided (with cotton or rayon) AF conductors twisted together without overall covering. 300V, 150°C.

AFI Arc Fault Interrupter.

AFPD Two or three AF conductors twisted together with cotton or asbestos braid overall. 300V, 150°C.

AFPO Two AF conductors, without individual braid, laid parallel and braided overall. 300V, 150°C.

AFS Two or three-conductor, heat-resistant cord with impregnated-asbestos insulation and rubber jacket. For use in damp locations. 300V.

AFSJ Same as AFS except: for lighter (junior) service. 300V.

AGC Automatic gain control.

Aging The change in properties of a material after exposure to an environment for period of time.

AGS Solid, stranded or flexible nickel conductor, silicone-impregnated asbestos insulation with glass braid. For appliance wiring. 300V, 200°C.

AI Appliance wire same as type A except: moisture-resistant as well as heat and flame-resistant. Dry locations only. Without braid. 300V, 125°C.

AIA Felted asbestos fibers with out asbestos or glass braid. Impregnated with heat, flame and moisture-resistant compound. 600V. Dry locations only - 125°C.

Air Core Cable A telephone cable in which the interstices in the cable core are not filled with a moisture barrier.

Air Spaced Coaxial Cable One in which air is the essential dielectric material. A spirally wound synthetic filament or spacer may be used to center the conductor.

AL or ALS Used as a suffix to denote a wire or cable having an aluminum sheath.

Allowable Ampacity As found in NEC tables 310-16 through 310-19 are based on time honored experience. (See also Ampacity)

Alloy A combination of two or more metals to form a new or different metal.

Alpeth A telephone cable having an aluminum screen.

Alternating Current (AC) An electric current that periodically reverses direction of electron flow. The number of full cycles occurring in a given unit of time (one second) is called the frequency of the current.

Alternating Current Resistance The resistance offered by a circuit to the flow of alternating current.

AM Amplitude modulation.

Ambient Conditions existing at a location prior to energizing of equipment (example:ambient temperature).

Ambient Temperature Any all-encompassing temperature within a given area.

American Wire Gage A standard used in the determination of the physical size of a conductor determined by its circular mil area. Usually expressed as AWG up to 4/0 AWG.

Ampacity The RMS current that a device can carry within specified temeperature limitations in a specified environment: dependent upon

a) temperature rating

b) power loss

c) heat dissipation. (See also Allowable Ampacity)

Ampere Current flow of one coulomb per second.

Ampere-Turn The product of amperes times the number of turns in a coil.

Amplitude The maximum value of a varying waveform.

AN Aircraft wire.

Analog Data from continuously varying physical quantities.

ANI A voluntary unincorporated association of companies providing property and liability insurance for US nuclear power plants; formerly NELPIA.

Anneal Softening material (such as copper) by means of heat with subsequent cooling to rend it less brittle.

ANSI (American National Standards Institute) An organization that publishes nationally recognized standards and provides liaisons with international standards developing organizations.

Antioxidant A substance that prevents or slows down oxygen decomposition of a material.

Antiozonant A substance that prevents or slows down material degradation due to ozone reaction.

Apparatus General designation for large electrical equipment applied in industrial facilities such as industrial machinery integrated to perform specific functions. For example; generators, motors, transformers, VPI systems, material handling systems, etc.

Apparatus Wire and Cable Insulated wire and cable used in electrical apparatus and in connecting this apparatus to a power source.

Appliance Utilization equipment, generally for commercial and residential applications, normally built in standardized sizes or types, installed or connected as a unit to perform one or more functions such as clothes washer, air conditioning, coffee pot, etc.

Approved Acceptable to the authority having legal enforcement. A product that has been tested by a nationally recognized lab against established standards and found suitable for general application.

Armature Rotating machine: the member in which alternating voltage is generated. Electromagnet: the member that is moved by magnetic force.

Armored Cable (AC) Fabricated assembly of insulated conductors in a flexible metallic enclosure with internal bonding strip in intimate contact along entire length.

Arrhenius Plot A method used to predict time-to-failure, based on a device's performance at different temperatures.

ASE Service entrance cable, above ground use. Some constructions suitable for underground use. Flame-resistant, moisture-resistant, abuse-resistant covering.

Askarel Synthetic insulating oil that is non-flammable but very toxic. Has essentially been replaced by silicone and vegetable oils.

ASP A filled direct burial telephone cable used in areas subject to rodent attack. It consists of a filled cable core, corrugated aluminum screen, corrugated steel tape, flooding compound and polyethylene sheath.

ASTM (American Society for Testing of Materials) A group that writes material specifications and standards for testing materials.

ATH Aluminum trihydrate - inert material used as filler to achieve flame retardancy in cable insulation and jacketing.

Attenuation Power loss in an electrical system expressed in decibels per unit length of cable.

Attenuation Constant A rating for a cable or other transmitting medium that is the relative rate of amplitude decrease of voltage or current in the direction of travel. It is measured in decibels per unit length of cable.

Audio A term used to describe sounds within the range of human hearing. Also used to describe devices that are designed to operate within this range.

Audio Frequency Band of Frequency that is audible to the human ear. Usually 20-20,000 cycles per second.

Autocatalytic Degradation Products of the initial phase of degradation accelerate the rate at which subsequent degradation occurs.

Autotransformer Any transformer where primary and secondary connections are made to a single cell.

AV or AVC Asbestos and varnished-cambric insulated power and control cables.

AVA Impregnated asbestos and varnished-cambric insulated, with asbestos or glass braid. 600V, 110°C.

AVB Same as AVA except: with cotton braid. 600V, 90°C.

AVL Same as AVA except: lead sheath replaces asbestos or glass braid. 600V-110°C, 5,000V-100°C.

AVPD Two or three-conductor heat and moisture-resistant cord, asbestos and varnished-cambric insulation with asbestos braid. Round construction, flame-retarding, moisture-resisting finish. 600V. Damp locations - 100°C.

AVPO Same as AVPD except: two-conductor flat construction.

AWG American Wire Gauge. Based on the circular mill system. 1 mil equals .001".

AWM Appliance wiring material.


B Same as AVC. Motor lead wire.

B+S Brown and Sharpe wire gauge - same as AWG.

Backfill The materials placed to fill an excavation, such as sand in a trench.

Balanced Line A cable having two identical conductors with the same electrocmagnetic characteristics in relation to other conductors and to ground.

Ballast A device designed to stabilize current flow.

Band Marking A continuous circumferential band applied to a conductor at regular intervals for identification.

Bandwidth The difference between the upper and lower limits of a given band of frequencies. Expressed in Hertz.

Bank Wire An insulated wire used for the interconnection of selector switches in automatic telephone exchanges.

Bare Conductor A conductor not covered with insulating material. For use in electrical grounding systems, and on insulators for overhead transmission and distribution applications. Available Bare or Tinned, soft (annealed), medium hard, and hard drawn.

Bare Copper Solid Conductor (See Bare conductor).

Bare Copper Stranded Conductor (See Bare conductor). Stranded conductors offer greater flexibility than solid.

Base Ambient Temperature The temperature of a cable group when there is no load on any cable of the group out of the duct bank containing the group.

Basic Conductor Load The limiting conductor load per unit length assumed for the purposes of design.

Battery Cable A single conductor cable, insulated or uninsulated, used for carrying current from batteries to the point power is needed. Also used for grounding.

BDC Plastic busdrop cable.

Bedding A layer of material applied to a cable immediately after armoring.

Bel A unit that represents the logarithm of the ratio two power levels. (See decibel).

Beldfoil® Belden trademark for highly effective electrostatic shield using reinforced metallic foil.

Beldsol® Solderable Belden magnet wire combining firms of polyurethane for excellent dielectric characteristics of nylon for mechanical protection.

Bell Wire Insulated copper wire for making doorbell and thermostat connections in homes.

Belted Cable A multi-conductor cable having a layer of insulation over the assembled insulated conductors.

BIL (Basic Impulse Level) A reference impulse insulation strength.

Binder Usually a spirally served tape or thread used for holding assembled cable components in place waiting further manufacturing operations.

Birdcage The undesired unwinding of a stranded cable.

Bonded Flat Cable Flat cable consisting of individually insulated conductors lying parallel and bonded together, application in electronics, telecommunications or computers.

Bonding The method used to produce good electrical contact between metallic parts of any device. Used extensively in automobiles and aircraft to prevent static buildup. Also refers to the connectors and straps used to bond equipment.

Booster A device inserted into a line (or cable) to increase the voltage. Boosting generators are also used to raise the level of a DC voltage. Boosting transformers are usually employed to raise AC voltages. The term booster is also applied to antenna preamplifiers.

Borehole Cable Vertical riser cables in mines.

Braid A fibrous or metallic group of filaments interwoven in cylindrical form to form a covering over one or more wires.

Braid Angle Determination of the braid configuration relating to the angle of the braided filaments or fibers in relationship to the axis of the cable being braided.

Braid Carrier A spool or bobbin on a braiding machine holding one group of strands or filaments consisting of a specified number of ends. The carrier revolves during the braiding operation.

Braid Ends Number of strands used to make up one carrier. The strands are wound side by side on the carrier bobbin and lay parallel in the finished braid.

Braider A machine used to apply a woven fibrous or metallic braid over a cable diameter.

Brake Wire Wire used in mobile home, travel and truck trailers to supply current to the electrical braking system.

Branch Circuit Cable Appropriately rated cable for its routing, support, and environmental conditions, used to feed utilization equipment such as motors, heaters, appliances, lighting, and sub-panels.

Breakout Wire or group of wires in a multi-conductor configuration that terminate somewhere other than at the end of the configuration.

Bridge A circuit that measures by balancing four impedances through which the same current flows. Wheatstone - resistance; Kelvin-low resistance; Scherling capacitance - dissipation factor; dielectric constant; Wien capacitance - dissipation factor.

BS British Standard.

BSC Bare soft copper-uncoated annealed copper.

Building Wire Wire used for light and power in permanent installations utilizing 600 volts or less. Usually in an enclosure and not exposed to outdoor environments.

Buna-S A synthetic rubber insulation of styrene butadiene; was known as GR-S, now as SBR.

Bunch Strand Any number of conductor strands twisted together in one direction with the same lay length.

Buried Cable A cable installed directly in the earth without use of underground conduit. Also called direct burial cable.

Busbar Wire Uninsulated tinned copper wire used as a common lead.

Butt Wrap A spirally wrapped tape over a cable core where the trailing edge of one wrap just meets the leading edge of the preceding wrap with neither overlap nor spacing.

Butyl Rubber A synthetic rubber with good electrical insulating properties.

BW Braided wire armor. Basket weave.

BX Armored building wire. 600V.


C Lamp cord, two or more conductors twisted together. Rubber insulation, cotton braid. For pendant or portable use in dry places. No overall covering. 300V or 600V, 60°C.

C Symbol designation for, capacitance, bias supply and centigrade.

Cable A conductor with insulation, or a stranded conductor with or without insulation and other coverings or combination of conductors insulated from one another (multi-conductor cable).

Cable-in-Duct System for direct burial in which a flexible conduit is extruded over electrical cables for a single preassembled unit.

Cabling The act of twisting together two or more insulated components by machine to form a cable.

CAC Flexible copper, synthetic tapes, felted asbestos and lacquered braid. 1,000V, 125°C.

Candela (CD) The basic SI unit for luminous intensity.

Capacitance The ratio of electrostatic charge on a conductor to the potential difference, between the conductors or between a conductor and earth.

Capacitive Charge Amount of current to maintain a particular voltage on a cable due to capacitance.

Capacitive Coupling Electrical interaction between two conductors caused by the incapacitance between them.

Capacitive Reactance The opposition to alternating current due to the capacitance of a capacitor, cable or circuit. It is measured in ohms and is equal to 1/6.28fC where f is the frequency in Hz and C is the capacitance in farads.

Capacitor Two conducting surfaces separated by a dielectric material. The capacitance is determined by the area of the surfaces, type of dielectric and spacing between the conducting surfaces.

Capillary Action The phenomenon of liquid rising in a small interstice due to surface tension.

Catenary Wire A wire or strand, usually of high tensile steel, which is attached to poles and which supports the weight of a cable either by suspenders or by being included in the make-up of the cable.

Cathode The negative electrode through which current leaves a non-metallic conductor, such as an electrolytic cell. The positive pole of a storage battery. A vacuum tube - the electrode that emits electrons.

Cathodic Protection Reduction or prevention of corrosion by making the metal to be protected the cathode in a direct current circuit.

Cathodic Protection Cable Stranded copper conductor insulated with a black high molecular weight polyethylene (HMWPE) compound that provides excellent abrasion, crush, chemical, oil and moisture resistance. Also resists electroendosmosis. 600V, 75°C. Suitable for direct burial for use in cathodic protection systems for pipelines, storage tanks and other buried or water-submerged metallic structures.

CB Rubber insulated brewery cord, with weatherproof braid on each conductor. Twisted, no overall covering.

CBO Neoprene insulated brewery cord for use in damp locations.

Cellular Polyethylene Expanded or "foam" polyethylene, consisting of individual closed cells of inert gas suspended in a polyethylene medium, resulting in a desirable reduction of dielectric constant.

CEN The European Committee for Standardization.

Ceramic Product made from inorganic, non-metallic materials fused or fired at high temperatures; used as insulation when extremely high temperatures are to be encountered.

CF Fixture wire, heat-resistant, with flame-retardant, moisture-resistant impregnated cotton insulation. With or without plain or fancy cotton or rayon braid. 300V, 90°C.

CFC Two or three CF type wires twisted together  without overall covering. Color-coded. 300V, 90°C.

CFPD Two or three CF type wires twisted together with overall braid. Color-coded. 300V, 90°C.

CFPO Two CF type wires lay parallell with overall braid. Color-coded. 300V, 90°C.

CFR (Code of Federal Regulations) The general and permanent rules published in the Federal Register by the executive departments and agencies of the federal government. For example: Title 30-Mineral Resources, Chapter I=MSHA (Mesa); title 29-Labor, Chapter XVII-OSHA; title 10-Energy, Chapter I=NRC.

Characteristic Impedance In a transmission cable of infinite length, the ratio of the applied voltage to the resultant current at the point the voltage is applied. Or, the impedance that makes a transmission cable seem infinitely long, when connected across the cable's output terminals. For a waveguide, it is the ratio of RMS voltage to total RMS longitudinal current at certain points on a diameter, when the waveguide is match-terminated.

Charging Current (Ic) The current needed to bring the cable up to voltage, determined by capacitance of the cable, after withdrawl of voltage the charging current returns to the circuit. The charging current will be 90° out of phase with the voltage.

Circuit A system of conducting mediums designed to pass an electric current. When the continuity of the circuit is broken, it is called an open circuit; when continuity is maintained, it is called a closed circuit.

Circuit-Sizes A popular term for building wire sizes 14 through 10 AWG.

Circular Mil (CM) A measurement used in determining the area of wire. The area of a circle 0.001 inches in diameter. Sizes are typically expressed in thousands of CM, kcmil, or MCM. Sizes larger than 4/0 AWG are specified kcmil. "MCM" is replaced by "kcmil".

Clad Wire Wire covered with a relatively heavy coating of a different metal, such as copperweld (copper over steel or alum-o-weld-aluminum over steel, accomplished by rolling, shaping and/or drawing dependent upon end use).

Coated Wire Wire covered by a relatively thin coating of a different metal such as tin, zinc, or other alloy by a dip bath and wipe process, often at high speeds in line with insulating equipment.

Coaxial Cable A cylindrical transmission line comprised of a conductor centered inside a metallic tube or shield, separated by a dielectric material, and usually covered by an insulating jacket.

Coil Effect The inductive effect exhibited by a spiral wrapped shield, especially above audio frequencies.

Cold Bend Test procedure whereby a sample of wire or cable is wound around a mandrel of a specified size within a cold chamber, at a specified temperature for a given number of turns at a given rate of speed. The sample is then removed and examined for defects or deterioration in the materials or construction.

Cold Flow Permanent deformation of the insulation due to mechanical forces without the aid of heat softening of the insulating material.

Cold Joint A soldered joint made with insufficient heat.

Cold Work The hardening and embrittlement of a metal by repeated flexing action.

Color-Code A color system for circuit idenification by use of solid colors, tracers, braids, surface printing, etc.

Composite Cable A multi-conductor cable containing two or more types of components.

Compound An insulating, semi-conducting, or jackting material made by mixing two or more ingredients.

Compounding The mixing together of two or more different materials to make one material.

Compression Lug or Splice Installed by compressing the connector onto the strand, hopefully into a cold weld.

Concentric Mining Machine Cable

Construction A: Center is flexible stranded copper insulated with rubber 1/64" thicker than NEC's dimension. This is finished with a tape and a braid. Over this are placed fine wires equal in area to the center conductor. A belt of rubber 1/64" less than the first belt is now applied and the whole cable finished with tape and double braid.

Construction B: Same as "A" except: no outer belt of rubber.

Concentric Stranding A group of uninsulated wires twisted so as to contain a center core with one or more distinct layers of spirally wrapped, uninsulated wires laid overall to form a single conductor. When more than one layer is present each layer must have a different lay length.

Cencentricity The measurement of the location of the center of the conductor with respect to the geometric center of the circular insulation.

Conductivity The ability of a material to alow electrons to flow, measured by the current per unit of voltage applied. Also, it is the reciprocal of resistivity.

Conductor Any material capable of easily carrying an electrical charge.

1) Bare conductor - conductor having no covering or insulation

2) Covered conductor - conductor encased within material not recognized as insulation

3) Insulated conductor - a conductor encased in a material recognized as insulation

Conductor Stress Control The semi-conducting layer applied to make the conductor a smooth surface in intimate contact with the insulation.

Conduit A tube or trough for protecting electrical wire and cables. It may be a solid or flexible tube of metallic or non-metallic material.

Connection Diagram (see wiring diagram)

Continuous Vulcanization (CV) Simultaneous extrusion and vulcanization of wire coating materials.

Contrahelical The application of two or more layers of spirally twisted, served, or wrapped materials where each successive layer is wrapped in the opposite direction to the preceding layer.

Control Cable A multi-conductor cable made for operation in control or signal circuits, relatively small in size, and with relatively small current ratins.

Convection A conveying or transference of heat or electricity by moving particles of matter.

Co-Polymer Two or more monomers polymerized together to form a different material.

Cord A small, very flexible insulated cable.

Core A component or assembly of components over which other materials are applied, such as, shield, sheath, or armor.

Corona A discharge due to ionization of a gas (usually air) due to a potential gradient exceeding a certain critical value.

Corona Extinction Voltage The minimum voltage that sustains corona, determined by applying a corona producing voltage then decreasing the voltage until corona is extinct.

Corona Initiation Point The critical value in the application of an electrical potential where corona is first noticed by the detection device.

Corona Test A test for finding the corona extinction and initiation voltage levels, low levels of extinction or initiation voltage indicate impurities in insulation, or voids within the insulation, or voids between insulation and shield, or broken shields.

Corrosion The process or result of a material being eaten or worn away, usually by chemical reaction.

Coulomb Quantity of electricity or electrical charge. One coulomb equals one ampere-second: 1C=1s•A.

Counter Emf The voltage opposing the applied voltage and the current in a coil, caused by a flow of current in the coil.

Counter-Poise Wire Bare copper. To offset the impact of lightning surges along high voltage overhead lines and around base of towers. Counter-poise wire is connected to overhead ground wire and towers and buried. Numerous methods of application are used, dependent upon resistance of soil at tower base. Sizes are usually 2 AWG or 4 AWG.

Coupling The transfer of energy between two or more cables or components of a circuit.

CPE® Dow Chemical trademark for chlorinated polyethylene.

CPS Cycles per second (see Hz).

Creepage Surface The insulating surface between a conductor and ground in cable splices and terminations.

Crimp Termination A wire termination that is applied by physical pressure of terminal to wire.

Cross Sectional Area The area of the cut surface of an object cut at right angles to the length of the object.

Cross Talk Electrical interference between two adjacent insulated conductors whereby a signal in one of the conductors will be picked up by the adjacent conductor.

Crossing Structure A structure built of poles and cross arms (sometimes rope and cords) used when conductors are strung over roads.

Cross-linked Inter-molecular bonds produced between long chain molecules in a material to increase molecular size by chemical or electron beam, resulting in a change in physical properties in the material, usually improved properties. For example; peroxide is heat activated and silane is moisture activated.

Cross-linked Polyethylene (XLP or XLPE) A polymerized ethylene insulation having excellent dielectric properties.

Cross-talk A type of interference caused by audio frequencies from one line being coupled into adjacent lines. The term is loosely used also to include coupling at higher frequencies.

CSA Canadian Standards Association.

CSPE (Hypalon®) Insulating and jacketing compound based on chlorosulfonated polyethylene. Also known as Hypalon®.

Cure To change the physical properties of a material by chemical reaction, by the action of heat and catalysts, alone or in combination, with or without pressure.

Current The rate of transfer of electricity. 1 ampere=the transfer of one coulomb per second.

Current Carrying Capacity The current a conductor of given size is capable of carrying safely without exceeding its own insulation and jacket temperature limitations.

Current Penetration The depth a current of a given frequency will penetrate into the surface of a conductor carrying the current.

Cut-Through Resistance The ability of a material to withstand mechanical pressure, usually a sharp edge or prescribed radius, without separation.

CV Continuous vulcanization.

CX Two-conductor, #18 AWG, rubber insulated, twisted Christmas tree cord. 300V.

CXT Two-conductor, #18 AWG, plastic-insulated twisted Christmas tree wire. 300V.


D Used as a suffix to indicate a twin wire with two insulated conductors lay parallel under an outer, non-metallic covering.

Db Decibel.

DC Direct current.

DC Resistance Resistance offered by a circuit to the flow of direct current.

DCR Direct current resistance.

Decibel Unit to express differences of power level. Example: the decibel is 10 times the common logarithm of the power ratio. It is used to express power gain in amplifiers or power loss in passive circuits or cables.

Delay Line A cable made to provide very low velocity of propagation with long electrical delay for transmitted signals.

Delta Connection Interconnect of three electrical equipment windings in delta (triangular) fashion.

Demand The measure of the maximum load of a utility customer over a short period of time. The load integrated over a specified time interval.

Denier A term describing the weight of a yarn (not cotton or spun rayon) that determines its physical size.

Derating Factor A factor used to reduce a current carrying capacity of a wire when used in other environments from that for which the value was established.

Device Operating element such as a relay, contactor, circuit breaker, switch, valve or governor, used to perform a given function in the operation of electrical equipment.

Dew Point The temperature at which vapor starts to condense (liquefy) from a gas vapor mixture at constant pressure.

Dielectric An insulating material usually having a very low loss factor.

Dielectric Absorption The charge stored in insulation. This is evidenced by the decrease of current flow after the application of DC voltage.

Dielectric Breakdown Any change in the properties of a dielectric that causes it to become conductive. Normally results in a catastrophic failure of insulation.

Dielectric Constant Insulation property (K): ratio of the parallel capacitance (C) of a conductor configuration with the insulation as the dielectric, versus the capacitance of the same conductor configuration with a vacuum as the dielectric.

Dielectric Dispersion The change in relative capacitance due to change in frequency.

Dielectric Heating The heating of an insulating material when placed in a radio frequency field, caused by internal losses during the rapid polarization reversal of molecules in the material.

Dielectric Loss The power dissipated in a dielectric as a result of the friction produced by molecular motion when an alternating electric field is applied.

Dielectric Phase Angle Angular difference in phase between the sinusoidal alternating potential difference applied to a dielectric and the component of the resulting alternating current.

Dielectric Strength The maximum applied voltage potential that does not damage an insulating material. Usually rated V/mil.

DIN Deutsches Institut für Normung eV.

Direct Capacitance The capacitance measured directly from conductor to conductor through a single insulating layer.

Direct Current (DC) Electrical current that flows in one direction only. Flow may be constant or pulsating as long as movement is in the same direction.

Direct Current Resistance (See DC resistance).

Direction of Lay The direction of twist, either clockwise or counter clockwise, of a conductor or group of conductors when looking axially down a cable length.

Dissipation Factor Energy lost, because of capacitance, when voltage is applied across insulation.

Distortion An undesired change in waveform as the signal passes through a device.

Distribution Cable In a CATV system, the transmission cable from the distribution amplifier to the drop cable.

DLC Diesel locomotive cable.

DLO Same as DLC except oil resistant.

DR Rubber range and dryer cord (CSA).

Drain Wire An uninsulated wire in direct contact with a shield throughout its length, used as an aid for terminating the shield.

Drawing Pulling a metal through a die or series of dies for reduction of a diameter to specified size.

DRO Oil-resistant range dryer cord (CSA).

Dual Coaxial Cable Two individually insulated conductors laid parallel or twisted and placed within an overall shield and sheath.

Duct An underground or overhead tube used for carrying electrical conductors.

Duofoil® Belden trademark for a shield in which metallic foil is applied to both sides of a supporting plastic film.

Duplex-Mining Machine Cable Double braid or triple braid, flexible stranded copper conductor rubber-insulated. Each conductor finished with WP braid. Two conductors laid side by side and covered with two or three braids of hard cotton which is then saturated with WP compound.

Durometer A measurement denoting the hardness of a substance (usually of thermosetting and thermoplastic materials).


E Elevator lighting and control cable. Thermoset insulation, three overall braids, outer one flame-retardant and moisture-resistant. May have steel supporting strand in center. 300V.

Earth British terminology for zero reference ground.

Eccentricity Like concentricity, a measure of the center of a conductor with respect to the center of the insulation; expressed as a percentage displacement.

ECTFE (Halar®) Ethylene chlorotrifluoro ethylene.

EIA Electronic Industries Association (formerly RMA or RETMA).

Elastomer Any material that will return to its original dimensions after being stretched or distorted.

Electric Gradient The space rate of change of potential ant a point in the direction of the greatest change.

Electrical Length The length of a cable expressed as degrees of a cycle or fraction of a wavelength for the signal transmitted. The equivalent electrical length of a cable equals the physical length times the square root of the dielectric constant.

Electro Osmosis The movement of fluids through diaphragms because of electric current.

Electrode A conductor through which a current enters or leaves an electrolytic cell, arc furnace, vacuum tube, gas discharge tube or other non-metallic conductor.

Electroendosmosis Combined deteriorating effect of endosmosis and DC voltage on thermoplastic insulation.

Electrolysis The production of chemical changes by passage of current through an electrolyte.

Electrolytic Corrosion Corrosion by means of electrochemical erosion.

Electrolytic Tough Pitch The method of raw copper preparation to ensure a good physical and electrical grade copper finished product.

Electromagnet A device consisting of a ferromagnetic core and a coil that produces appreciable magnetic effects only when an electric current exists in the coil.

Electromagnetic Magentism caused by the flow of an electric current.

Electromagnetic Coupling The transfer of energy by means of a varying magnetic field. Inductive coupling.

Electromechanical Cables Applies to dual purpose composite cable made up of support strands or cables capable of supporting predetermined loads together with communication coaxial, power or combination of all as integral members of finished cable.

Electromotive Force Force which determines the flow of electricity; a difference of electrical potential (voltage).

Electron An elementary particle containing the smallest negative electric charge. Charge= 0.16 attocoulomb.

Electron Volt A measure of the energy gained by an electron falling through an electric field produced by one volt.

Electroplate The term used to indicate the application of the metallic coating on a surface by means of electrolytic action.

Electro-positive A substance that has a tendency to unit electrons in electrolysis leaving it with a positive charge.

Electrostatic Pertaining to static electricity, or electricity at rest. An electric charge, for example.

Electrostatic Coupling The transfer of energy by means of a varying electrostatic field. Capacitive coupling.

Elementary Schematic Graphical representation of electrical connections between devices, apparatus, and appliances. (See wiring diagram).

Elexar®(TPE) Shell trademark for thermoplastic elastomer.

Elongation at Break The tensile strain in a test piece stretched to breaking point, the conditions being such that the stress is substantially uniform over the cross section.

EMA (Electrical Moisture Absorption) A water tank test during which the same cables are subjected to voltage while the water is maintained at rated temperature, the immersion time is long. The object is to accelerate failure due to moisture in the insulation; simulates buried cable.

Embossing A means of marker identification by means of thermal indentation leaving raised lettering on the sheath material of cable.

Emergency Overloads Loads that occur when larger than normal currents are carried through a cable or wire over a short period of time.

Emf Electromotive force.

Endosmosis The penetration of water into a cable by osmosis aggravated and accelerated by DC voltage on the cable.

Ends The number of wires or threads on a braider carrier.

Environment The parameters within which a system must operate.

Enviro-Plus® Service Wire trademark for conductors and cables insulated and jacketed with polyolefinic materials. Zero Halogen, Limited Smoke, Zero Lead Jacket. (Wire type designations - ZH). 600V.

EO Elevator lighting and control cable. Thermoset insulation, cotton braid, neoprene jacket. May have steel supporting strand in center. 300V.

EP, EPR, EPM, EPDM Designations for synthetic rubber insulation based upon ethylene-propylene hydrocarbon.

EPA (Environmental Protection Agency) The federal regulatory agency responsible for keeping and improving the quality of our living environment - mainly air and water.

EPDM Ethylene propylene diamine monomer.

EPR Ethylene propylene rubber.

ESS Extruded strand shield. A type of conductor stress control.

ET, ETLB, ETP, ETT Elevator lighting and control cable. Thermoplastic insulation, three braids, flame-retardant and moisture-retardant. May have steel supporting strand in center. 300V.

ETFE (Tefzel®) DuPont trademark for ethylene tetrafluoro ethylene.

Ethylene Propylene Rubber (EPR) A synthetic rubber insulation having excellent dielectric properties.

ETL Electrical Testing Laboratory.

EV Thermoset electric vehicle cable. Extra-hard usage. May contain optional data signal, communications, and optical fiber cables.

EVE Thermoplastic electric vehicle cable. Extra hard usage. May contain optional data signal, communications, and optical fiber cables.

EVJ Same as EV except: hard usage.

EVJE Same as EVE except: hard usage.

EVJT Same as EVT except: hard usage.

EVT Thermoplastic electric vehicle cable. Extra hard usage. May contain optional data signal, communications, and optical fiber cables.

Excitation Losses Losses in a transformer or electrical machine because of voltage.

Exothermic Characterized by the liberaton of heat.

Extrusion The forming of (relatively) long lengths of a material by forcing it, in a plastic of semi-liquid state, through an orifice. Upon emergence, the extruded material ordinarily is cooled or solidified into a solid.


F Flat band metallic armor.

F Thermoplastic underground feeder and branch circuit cable.

Farad A unit of electric capacitance.

FCC Flexible control cable.

Feeder Cable Appropriately rated cable for its routing, support, and environmental conditions. Serves as main circuit between power supply transformer and a main substation or switchboard or between a main substation or switchboard and a MCC or lighting panel.

FEP or FEPB Fluorinated ethylene propylene. 600V. Dry or damp location - 90°C. Dry locations (with glass braid) - 200°C.

FEXT Far end cross-talk.

FF-1 Fixture wire, flexible, rubber insulated, single conductor. 300V, 60°C.

FF-2 Same as FF-1 except: 600V.

Fiber Optics Transmission of energy by light through glass fibers.

Fibrous Filler A material used to fill interstices in cables made from fibers such as cotton, glass, etc.

Field Wire A light, small wire type usually produced in long lengths for use in communications in the field.

Figure 8 Cable An aerial cable configuration in which the conductors and the steel strand that supports the cable are integrally jacketed. A cross section of the finished cable approximates the figure "eight".

Filled Cable Construction where cable core is filled with material that prevents moisture from entering or passing through the cable.


a) A material used in the cable to fill large interstices between electrical components

b) A substance, often inert, added to a compound to improve properties and/or decrease cost.

Film Thin plastic sheeting.

Fission (Nuclear Power) The splitting of an atom into two fragments, by bombarding its nucleus with particles releasing high kinetic energy (32pJ) and two or three neutrons along with radiation. The most important type of fission is that caused by neutrons because it can be self-sustaining due to chain reactions, the newly released neutrons can cause other fissions to occur.

Flame-Resistance Ability of the material to extinguish flame once the source of heat is removed.

Flammability Measure of the materials ability to support combustion.

Flat Conductor A wire manufactured in a flattened form as opposed to round, or square, conductors.

Flat Under Carpet Cable Insulated copper tape to lay under carpets, thickness less than .04 inches, means it is indiscernible, yet available in sizes equivalent to 10 or 12 AWG building wire.

Flat Wire A rectangular wire having 0.188 inch thickness or less, 1 1/4 inch width or less.

Flex Life Ability of a conductor, wire or cable, to withstand repeated bending.

Flexible Cable A cable containing one or more cores, each formed of a group of wires, the diameters of the wires being sufficiently small to afford flexibility.


a) A material that helps produce fusion, as solder flux.

b) A continuous flowing or passing. (See magnetic flux).

Foamskin Polyethylene foam insulation with polyethylene outer skin.

Fraying The unraveling of a fibrous braid.

FRMR Flame-retarding, moisture-resisting finish.

FRP Fiberglass reinforced plastics.

FX Single rubber insulated Christmas tree wire with outer braid. 125V, 60°C.

FXT Single plastic-insulated Christmas tree wire. 125V, 60°C.


G Thermoset insulated, neoprene jacketed portable power cable with two to six #8 AWG or larger conductors with ground wires.

Gage or Gauge The physical size if a wire.

GALV Galvanized.

GFCI (Ground Fault Circuit Interrupter) A protective device that detects unbalanced current flow (approximately 6mA) and then interrupts the circuit to protect personnel.

GFEP (Ground Fault Equipment Protector) (See GFI).

GFI (Ground Fault Interrupter) A protective device that detects unbalanced current flow (normally in range of 30mA to 5A) and then interrupts the circuit to protect equipment or electrical systems.

G-GC A portable power cable similar to Type G, but also having a ground check conductor to monitor the continuity of the ground circuit.

GOR Gasoline and oil-resistant wire.

Ground To connect the earth or other large conducting body to serve as an earth.

Ground Check Conductor A conductor used in mining cables to monitor the continuity of the grounding circuit, so that a discontinuity or "open" in the grounding circuit causes the power conductors to be de-energized. Also called a "ground monitoring" conductor. Used in Types G-GC, SHD-GC, and MPF-GC. Abbreviated "GC", identified by a yellow-colored insulation.

Ground Fault A fault to ground.

Ground Support Cable A cable construction, usually rugged and heavy, for use in ground support control or power systems.

Grounding Wire or Conductor A conductor used to connect equipment or the grounded circuit of a wiring system to a grounding electrode or electrodes, usually colored green.

GRS A synthetic rubber insulation of styrene butadiene. (See Buna-S or SBR).

GTO Gas tube sign and oil-burner ignition cable. 5,000-15,000V.

Golf Course Sprinkler Cable Suitable for use as power and control conductors for golf course irrigation systems. 600V.

Guy Wire A tension wire connected to a tall structure and another fixed object to add strength to the structure.


H Shielded power cable. Multi-conductor cables have paper or varnished-cambric insulation applied directly over individual conductors. Spiraled metallic shielding tape over insulation with overall protective covering.

Halogens Materials such as bromine, chlorine, fluorine when added to cable insulation and jacketing acts as a flame retardant by eliminating oxygen surrounding cable when heated.

Hard Drawn Copper Wire Copper wire that has been drawn to size and not annealed.

Harness A group of conductors laid parallel or twisted by hand, usually with many breakouts, laced together or pulled into a rubber or plastic sheath, used to interconnect electrical apparatus and devices.

Hash Mark Stripe A non-continous, helical stripe applied to a conductor for a circuit identification.

Hazardous Atmosphere Ignitable vapors, dust or fibers that may cause fire or explosion.

HC Two or more conductor heater cord, asbestos and rubber insulation with cotton braid over each conductor. Twisted, no overall covering.

HDPE High-density polyethylene.

Heat Distortion Distortion or flow of a material or configuration due to the application of heat.

Heat Seal Sealing a tape wrap jacket by means of thermal fusion.

Heat Shock A test to determine stability of a material by sudden exposure to a high temperature for a short period of time.

Helical Stripe A continuous, colored, spiral stripe applied over the outer perimeter of an insulated conductor for circuit identification purposes.

Helix A spiral winding.

Henry An electrical unit denoting the inductance of a circuit in which a current varying at the rate of one ampere per second produces an electromotive force of one volt.

Hertz (Hz) Cycles per second - typically 50 or 60 hertz for power supplies. (See alternating current).

HF (Halogen Free) Cable that is free from halogen.

HF Polyethylene-insulated radio hookup wire with or without braid.

HFFR Halogen Free Flame Retardant.

High Impedance Generally 25,000 ohms or higher.

High Temperature Wire and Cable Wires and cables having thermal operating characteristics of 150°C or higher.

High Voltage Generally considered being a wire or cable with an operating voltage over 35kV.

Hi-Pot A test in which a potential (voltage) much higher than the rated is applied to a conductor in order to verify the integrity of the insulation. A normal DC Hi-Pot will include (Dielectric Absorption) + (Capacitive Charge) + (Leakage Current). Additional current will be from incipient or faulted condition.

HMPE High moelcular polyethylene.

HMWPE Highmolecular weight polyethylene.

Hook-Up Wire A wire used for low current, low voltage (under 1,000V) applications internally within enclosed electronic equipment.

Horizontal Stripe A colored stripe running horizontally with the axis of a conductor, sometimes called a longitudinal stripe, used as a means of circuit identification.

Hot Dip Covering of a surface by means of dipping the surface to be coated into a molten bath of the coating material.

Hot Modulus Stress at 100% elongation after five minutes of conditioning at a given temperature (normally 130°C).

Hot Stick A long insulated stick having a hook at one end which is used to open energized, exposed switches, etc.

HPD Rubber and asbestos insulated heater cord. No braid on individual conductors but with braid overall. Also made with neoprene insulation and no asbestos or PVC/NBR.

HPN Two-conductor, neoprene insulated heater cord. Parallel construction. Damp locations.

HS Rubber and asbestos insulated heater cord. Cotton serve and rubber jacketed overall. For use in damp locations #14 or #12 conductors. Also made with neoprene insulated inners and asbestos.

HSJ Same as type HS except: with #18 or #16 conductors and differing thickness of jacket.

HSJO, HSJOO Hard usage HSJ.

HSO Neoprene jacketed heater cord.

HSOO Extra hard usage HSO.

HV High voltage.

HW Radio hookup wire with polyvinyl chloride insulation. With our without nylon jacket, braid or shield. 2,500V.

Hybrid Cable (See composite cable).

Hydroscopic Readily absorbing and retaining moisture.

Hypalon® (CSPE) (See CSPE).

Hysteresis The time lag exhibited by a body in reacting to changes in forces affecting it, an internal friction.


I Interlocked armor of aluminum, bronze, or steel.

I Symbol used to designate current.

I²R Formula for power in watts, where I=Current in amperes, R=Resistance in ohms. (Also see watt).

ICEA Insulated Cable Engineers Association (was ICPCEA).

IEC International Electrotechnical Commission (Europe).

IEEE Institute of Electrical and Electronics Engineers.

IF Intermediate frequency.

Ignition Cable A cable designed primarily for automotive ignition systems.

Impact Strength Punishment a cable configuration can absorb without physical or electrical breakdown, by impacting with a given weight, dropped a given distance, in a controlled environment.

Impedance The ratio of the effective value of the potential difference between two terminals versus the effective value of the current flow produced by that potential difference.

Impedance Match A condition whereby the impedance of a particular circuit cable or component is the same as the impedance of the circuit or device to which it is connected.

Impedance Matching Stub A section of transmission line or a pair of conductors cut to match the impedance of a load. Also called matching stub.

Impedance Matching Transformer A transformer designed to match the impedance of one circuit to that of another.

Impregnate To fill the voids and interstices of cable or the fabric of a cable with a compound.

Induced Voltage A voltage produced in a conductor by a change in magnetic flux linking that conductor with an energized conductor.

Inductance That property of an electrical circuit where a varying current induces an electromotive force in that circuit or in an adjacent circuit.

Induction The phenomenon of a voltage, magnetic field, or electrostatic charge being produced in an object by lines of force from the source of such fields.

Induction Heating Heating a conducting material by placing it in a rapidly changing magnetic field. The changing field induces electric currents in the material and I²R losses account for the resultant heat.

Infrared Radiation Radiant energy within the wavelength range 780 to 1,000 nanometers, invisible energy given off by heated bodies which transmits heat and will pass through glass.

Input A signal, or power, which is applied to a piece of electric apparatus or the terminals on the apparatus to which a signal or power is applied.

Insertion Loss A measure of the attenuation of a device by determining the output of a system before and after the device is inserted into the system.

Insulated Wire A conductor of electricty covered with a non-conducting material.

Insulation A non-conductive material usually surrounding or separating two conductive materials. Often called the dielectric in a radio frequency cable.

Insulation Class Rating A temperature rating descriptive of classes of insulations for which various tests are made to distinguish the materials, not related necessarily to operating temperatures.

Insulation Level (Cable) The thickness of insulation for circuits having ground fault detectors which interrupt fault currents within:

a) 1 minute=100% level,

b) 1 hour=133% level,

c) over 1 hour=173% level.

Insulation Resistance The property of an insulating material that resists electrical current flow through the insulating material when a potential difference is applied.

Insulation Stress The molecule separation pressure caused by a potential difference across an insulator. The practical stress on insulation is expressed in volts per mil.

Integral Belt A layer of insulation or semi-conductive material applied usually by extrusion over two or more insulated, twisted or parallel conductors, to form a round, smooth diameter.

Integrated Dose (Nuclear Power) Cumulative radiation dosage over a given period of time.

Intercalated Tapes Two or more tapes of different material helically wound and overlapping on a cable to separate the materials.

Interconnecting Wire Wire for external use in electronic equipment exposed to physical abuse. Interconnecting wire encompasses both control and power circuits.

Interference Disturbances of an electrical or electromagnetic nature that introduce undesirable responses into other electronic equipment.

Interlocked Armor (See Metal Clad).

Intermediate Frequency A frequency to which a signal is converted for ease of handling. Receives its name from the fact that it is an intermediate step between the initial and final conversion or detection stages.

Interstice The space, valley or void left between or around the cabled components.

Intrinsically Safe Incapable of releasing sufficient electrical or thermal energy under normal or abnormal conditions to cause ignition of a specific hazardous atmospheric mixture in its most ignitable concentration.

Inverter Duty-Cable A cable specifically constructed to withstand and transmit repeated high voltage pules without undue physical or electrical degradation.

Ionization The act of splitting into or producing ions.

Ionization Factor This is the difference between percent dissipation factors at two specified values of electrical stress, the lower of the two stresses is usually so selected that the effect of the ionization on dissipation factor at this stress is negligible.

Ionization Voltage The potential at which a material ionizes. The potential at which an atom gives up an electron.

IPCEA (Insulated Power Cable Engineers Association The association of cable manufacturing engineers who make nationally recognized specifications and tests for cables.

IPE Irrdiated polyethylene tape.

IR Drop A method of designating a voltage drop in terms of both current resistance.

Irradiation The exposure of an insulation to high-energy emissions to favorably alter the molecular structure.

IRS Ignition radiation suppression.

Isolation The ability of a circuit or component to reject interference, usually expressed in db.


J Asphalted jute, non-metallic armor.

Jacket The material, usually an extruded plastic or elastomer, applied outermost to a wire or cable.

JCS Japanese Cable Maker's Association Standard.

Jet Starter Cable Single conductor-external aircraft power source, AC-DC with low temperature characteristics, like welding cable, SO or W. 600V.

JIS Japanese Industrial Standards.

Jumper Cables Extra flexible insulated cables equipped with clamp connectors used to bypass current. Where used to protect people, they must be rated to carry bolted fault current for the time it takes for protective devices to open the circuit. Usually clear jacketed so damage can be easily assessed. Size ranges of 2 AWG through 1,000 kcmil.

Junction A point in a circuit where two or more wires are connected.

Jute A natural fiber of plant base formed into ropelike strands. Used in cables for filling the interstices, to give a round cross section.

JWJ Jute, wire armor, jute.


K Constant used to denote insulation resistance.

Kapton® DuPont trademark for polyimide insulation.

Kcmil 1,000 circular mil. For example: 500 kcmil=500,000 circular mil.

Kilohertz 1,000 Hz.

Kilovolt 1,000 volts.

Kilowatt 1,000 watts.

Kirchoff's Laws The algebraic sum of the currents at any point in a circuit is zero. The algebraic sum of the product of the current and the impedance in each conductor in a circuit is equal to the electromotive force in the circuit.

KV Kilovolt 1,000 volts.

KVA Kilovolt ampere.

KW Kilowatt 1,000 watts.

Kynar® (PVDF) Pennwalt trademark for polyvinylidene fluoride.


L Denotes lead sheath.

L Symbol for inductance.

Lacquer The liquid resin or compound applied to a fibrous braid to prevent fraying, wicking, moisture absorption, etc., in the braid.

Laminated Flat Cable Flat cable consisting of insulated conductors lying parallel, adjacent conductors joined by a web. Application in electronics, telecommunication, computers, etc.

Laminated Tape A tape consisting of two or more layers, usually each layer being a different material sealed or laminated together to form one tape.

Lamp Cord Flexible stranded parallel two-conductor cord, rubber or plastic insulated. Used for speaker cord, fans, lamps, etc. where not subject to hard usage.

Lay The distance of advance of one member of a group of spirally twisted members, in one turn, measured axially.

Lay Direction The twist in the cable as indicated by the top strands while looking along the axis of the cable away from the observer. Described as "right hand" or "left hand".

LCDI Leakage current detector and interrupter.

Leakage Current The undesirable passage of current over the surface of or through an insulator.

Leakage Distance The shortest distance along an insulation surface between conductors.

LESCW Low energy safety circuit wire.

Level A measure of the difference between a quantity or value and an established reference.

LF Low frequency.

Life Cycle A test to determine the length of time before failure in a controlled, usually accelerated, environment.

Line Cord A cord terminating in a plug at one end used to connect equipment or appliances to a power outlet.

Line Drop A voltage loss occurring between any two points in a power or transmission line. Such loss, or drop, is due to the resistance, reactance, or leakage of the line.

Line Equalizer A reactance, inductance and/or capacitance, connected in series with a transmission line to alter the frequency-response characteristics of the line.

Line Level The level of a signal at a certain point on a transmission line. Usually expressed in decibels.

Line Voltage The value of the potential existing on a supply or power line.

Lissajous Figure A special case of an x-y plot in which the signals applied to both axes are sinusoidal functions, useful for determining phase and harmonic relationships.

Litz Wire A conductor made up of several insulated twisted wire to reduce skin effect and lower radio frequency losses.

Load A device that consumes or converts the power delivered by another device.

Loaded Line A transmission line that has lumped elements, inductance or capacitance, added at uniformly spaced intervals. Loading is used to provide a given set of characteristics to a transmission line.

Loading (See loaded line).

LOCA (Loss of Coolant Accident) Nuclear power. The test to stimulate nuclear reactor accident exhibited by high radiation, high temperature, etc.

LOI Limited Oxygen Index. Minimum concentration of oxygen required supporting a flame on a test specimen.

Longitudinal Wrap A tape applied longitudinally with the axis of the core being covered, as opposed to a helical, or spiral, tape wrapped core.

Longwall Machine (Mining) A machine used to undercut coal at relatively long working spaces.

Loop Resistance The total resistance of two conductors measured round trip from one end (twisted pair, shield and conductor, etc.).

Loss The portion of energy applied to a system that is dissipated and performs no useful work.

Loss Factor Equal to the product of insulation's dissipation and dielectric constant.

Low Energy Circuit Cable 2 parallel conductors with integral insulation. Ripcord feature. Suitable for direct burial. Landscaping and lighting applications. 150V.

Low Frequency A band of frequencies extending from 30 to 300 kHz in the radio spectrum, designated by the Federal Communications Commission.

Low Impedance Generally 1 through 600 ohms.

Low Loss Dielectric An insulating material, such as polyethylene, that has a relatively low dielectric loss making it suitable for transmission of radio frequency energy.

Low Noise Cable A cable configuration constructed to eliminate unpredictable electrical disturbances caused by capacitance changes or self-generated noise induced by either physical abuse or adjacent circuitry.

Low Voltage Generally considered a wire or cable rated less than 1,000 volts.

Lug A termination, usually crimped or soldered to the conductor, with provision for screwin down to a terminal.

Lumen The derived SI unit for luminous flux.

LV Low voltage.

LW Radio hookup wire with polyvinyl chloride insulation. With or without nylon jacket, braid, or shielding braid. 300V.


M Mutual inductance.

M Suffix indicating two or more insulated, twisted conductors under an outer, non-metallic covering.

MA Milliampere (0.001 of an ampere).

Magnetic Field The region within which a body or current experiences magnetic force.

Magnetic Flux The rate of flow of magnetic energy across or through a surface (real or imaginary).

Marker Tape A tape laid parallel to the conductors under the sheath in a cable, imprinted with the manufacturer's name and the specification to which the cable is made. Other information such as date of manufacture may also be included.

Marker Thread A colored thread laid parallel and adjacent to the strands of an insulated conductor that identifies the cable manufacturer. It may also denote a temperature rating or a specification to which the cable is made.

MCM Thousand circular mils, for example, 500 MCM are 500,000 circular mils.

Mechanical Water Absorption A check of how much water will be absorbed by material in warm water for seven days (mg/sq in. surface).

Medium Voltage Generally considered to be a wire or cable rated 1-35kv.

Megahertz (Megacycle) One million cycles.

Megawatt 1,000,000 watts.

Megohm 1,000,000 ohms.

Melinex® ICI trademark for polyester. (See Mylar®).

Melt Extrude To heat a material above its crystalline melt point and extrude it through an orifice.

Melt Index The extrusion rate of a material through a specified orifice at specified conditions.


Metal-Clad (MC) Factory assemblies of one or more insulated conductors enclosed in armor of interlocking metal tape or smooth or corrugated metallic sheath. Adequate grounding path is supplied, typically via a separate conductor. The armor or sheath may be aluminum or galvanized steel. MC cable with interlocking armor is the most common.  

Metallic Shield Shield made of metal tape, metal braid, or wire serving. Copper is the predominant metal used.

MFD (See microfarad).

MgOH Magnesium hydroxide - inert material used as filler to achieve flame retardancy in cable insulation and jacketing.

Mho Inverse of resistance (1/0hm). Also referred to as Siemens.

MHz Megahertz, 1,000,000 cycles per second.

MI Mineral insulated. One or more conductors insulated with highly compressed refractory minerals and enclosed in a liquid-tight and gas-tight metallic tube sheathing. 600V. Dry and wet location - 90°C. Special applications - 250°C.

Microfarad 0.000001 farad.

Microhenry 0.000001 henry.

Microphonics Noise caused by mechanical excitation of a system component. In a single conductor microphone cable for example, the shield rubbing against the dielectric as the cable is flexed can cause microphonics.

Microwave A short electrical wave, usually a wavelength of less than 30 cm.

Microwave Frequency The frequency of a microwave, usually above 1,000 MHz per second.

Mil 0.001 inch.

MIL Military specification.

Millivolt 0.001 volt.

Mining Cable A floame-retardant cable especially constructed to withstand long time immersion or exposure to moisture for underground use in the environment of a mine or tunnel.

Mis-match A termination having a different impedance than that for which a circuit or cable is designed.

ML Single-conductor, paper-lead cables twisted together without overall covering (same as SL).

Type A: AVC mine locomotive cable.

Type B: motor lead wire.

MM Mining machine cable.

Modulus of Elasticity The ratio of stress to strain in an elastic material.

Moisture-Resistance The ability of a material to resist absorbing moisture from the air or when immersed in water.

Molded Plug A connector molded on either end of a cord or cable.

Monofilament A single strand filament as opposed to a braided or twisted filament.

Monomer A single property or ingredient. A molecule of low molecular weight used as a starting material for polymerization to produce molecules of higher molecular weight called polymers.

Motor Lead Wire Wire that connects to the usually fragile and easily damaged magnet wire found in coils, transformers, and stator or field windings. General requirements are abrasion resistance, toughness, flexibility, dielectric strength, thermal resistance, and low percent of extractables (where applicable such as in hermetic wires).

MPF Mine power feeder. 5-8-15KV.

MRFR Moisture-resistant, flame-retardant finish.

MSHA (Mine Safety and Health Administration) The federal enforcement agency for employee safety in mines and mills. Part of the Department of Labor; formerly known as MESA, Bureau of Mines. MSHA was enacted by Public Law 91-1973, amended by Public Law 95-164 known as the Federal Mine Safety and Health Act of 1977; the MSHA regulations appear in CFR Title 30, Chapter 1.

MTW Thermoplastic-insulated machine tool wire. 600V. Wet locations - 60°C. Dry locations - 90°C.

Multi-conductor More than one conductor within a single cable complex.

Mutual Capacitance Capacitance between two conductors when all other conductors, including ground, are connected together and then regarded as an ignored ground.

mV Millivolt, 0.001 volt.

MV Medium voltage.

MV Cable Operating Temperatures









Short Circuit Clearing Time



mW Milliwatt, 0.001 watt.

MW Radio hookup wire with polyvinyl chloride insulation and plain or nylon jacket, or braid or shield. 1,000V.

MYD Marina Yard and Dock Cable.

Mylar® DuPont trademark for polyethylene terephthalate (polyester) film. (See Melinex®)


NBC A blend of acrylonitrile-butadiene rubber and polyvinyl chloride (PVC). Used for jacketing.

NBR Butadiene acrylonitrile copolymer rubber, a material with good oil and chemical resistance.

NBR/PVC A blend of acrylonitrile-butadiene rubber and polyvinyl chloride (PVC). Used for jacketing.

NEC National Electric Code.

NEMA National Electrical Manufacturers Association.

Neoprene Trade name for polychloroprene, used for jacketing. (See polychloroprene).

NES Naval Engineering Standards (UK Ministry of Defence).

NESC National Electric Safety Code.

NEXT Near end cross-talk.

NFPA National Fire Protection Association.

NM Non-metallic sheathed cable, braid or plastic covered. 600V. Dry locations - 60°C.

NM-90 Non-metallic sheathed cable. 600V. Dry locations - 90°C. (See ROMEX°).

NMC Non-metallic sheathed cable, plastic or neoprene covered. 600V. Wet or dry locations - 60°C.

Noise In a cable or circuit any extraneous sounds or signals which tend to interfere with the sound or signal normally present in or passing through the system.

Nomex® DuPont trademark for a temperature resistant, flame-retardant aramid fiber material.

Nomograph A chart or diagram with which equations can be solved graphically by placing a straightedge on two known values and reading the answer where the straightedge crosses the scale of the unknown value.

Non-Contaminating Compound A compounded material that will not leach ingredients so as not to contaminate or degrade adjacent materials under given environmental conditions.

Non-Metallic Shield Semi-conducting shield ("semicon"). Provides protection against corona. Metallic shields are usually applied over semi-conductors to provide a path of sufficient conductivity to carry charging and/or fault current.

Nordel® DuPont trademark for EPDM synthetic rubber.


NRR Non-returnable reels.

Nylon An abrasion-resistant thermoplastic with good chemical resistance.


OD Outside diameter.

OHM Unit of electrical resistance.

Ohm's Law Stated E=IR, I=E/R, or R=E/I, the current I in a circuit is directly proportional to the voltage E, and inversely proportional to the resistance R.

Ohm-Pound/Mile The resistance of a wire one pound in weight and one mile in length.

Operating Temperature The temperature at which a device is designed or rated for normal operating conditions, for cables, the maximum temperature for the conductor during normal operation.

Optimization The procedure used in the design of a system to maximize or minimize some performance index.

Organic Fiber A fiber derived or composed of matter originating in plant or animal life or composed of chemicals of hydrocarbon origin either natural or synthetic.

OSHA Occupation Safety and Health Act of 1970 administered by US Department of Labor which establishes standards and safety requirements for businesses. The OSHA regulations for electrical safety appear in CFR29 subparts S & R.

Osmosis The diffusion of fluids through membranes.

Outgassing Dissipation of gas from a material.

Output The useful power or signal delivered by a circuit or device.

Overcurrent The current that causes an excessive temperature rise in a conductor.

Overlap The amount the trailing edge laps over the leading edge of a spiral tape wrap.

Overload Capacity The maximum level of current, voltage, or power that a device can withstand before it is damaged.

Oxidation The process of uniting a compound with oxygen, usually resulting in an unwanted surface degradation of the material or compound.

Oxygen Index A test to rate flammability of materials in a mixture of oxygen and nitrogen.

Ozone Extremely reactive form of oxygen, normally occurring around electrical discharges and present in the atmosphere in small but active quantities. In sufficient concentrations, it can break down certain rubber insulation under tension, such as bent cable.

Ozone Resistance Tests A test to determine deterioration from ozone.

Ozone Test Exposure to a high concentration of ozone to give an accelerated indication of oxidation in normal environments and proximity to ozone producing apparatus.


P Two or more rubber insulated stranded conductors with cotton braid over each. Reinforced with overall covering of cotton braid over rubber filler. For pendant or portable use in damp locations. 300V-600V.

Paracril® Uniroyal trademark for nitrile rubber/PVC blend usually used for jacketing. (See NBR/PVC).

Parallel A construction in which two or more conductors are laid parallel and surrounded and separated by an insulating material.

Parallel Circuit A circuit in which the identical voltage is presented to all components and the current divides among the components according to the resistances or the impedances of the components.

Parallel Conductors Size 1/0 AWG and larger, that are electrically connected in parallel at both ends, to form a single conductor. Each leg of a circuit must have same physical and electrical characteristics.

Paste Extrude Fine powder is mixed with a lubricant and is forced through a die of given size, without heat, as opposed to melt extrude.

Patchcord A flexible piece of electrical cord terminated at both ends with plugs, used for interconnecting circuits on a patchboard.

PCG Portable mine cable with power, control and ground conductors.

PCP (Neoprene) Polychloroprene.

PD Thermoset or thermoplastic insulated stranded conductors with cotton braid over each. Conductors twisted with braid overall. Light duty, dry locations on appliances. 300V.

PE, XLP, or XLPE Designation for polyethylene insulation based upon ethylene hydrocarbon.

Peak The maximum instantaneous value of a varying current or voltage. Also called a crest.

Peak Voltage The maximum instantaneous voltage.

PEEK® ICI trademark for polyether ketone.

Percent Conductivity The conductivity of a material expressed as a percentage of that of copper.

Periodicity The uniformly spaced variations in the insulation diameter of a transmission cable that result in reflections of a signal, when its wavelength or a multiple thereof is equal to the distance between two diameter variations.

PFA Perfluoroalkoxy. 600V. Dry and damp - 90°C. Special applications - 200°C.

PFAH Same as PFA except: Dry location leads within apparatus 250°C.

PG Portable mine cables having power and ground conductors. 600V.

Phase A particular stage or point of advancement in an electrical cycle measured from some arbitrary point usually expressed in electrical degrees where 360° represents one cycle.

Phase Sequence The order in which the successive members of a periodic wave set reach their maximum values;

a) zero phase sequence-no phase shift

b) plus/minus phase sequence-normal phase shift.

Phase Shift A change in phase of a voltage or current after passing through a circuit or cable.

PIC A general term for any type of plastic insulated telephone cable.

PICK Distance between two adjacent crossover points of braid filaments. This measurement, in picks per inch, indicates completeness of coverage (the more per inch, the more complete the coverage).

Pickup Any device that is capable of transforming a measureable quantity of intelligence, such as sound, into relative electrical signals, e.g., a microphone.

Picofarad 0.000000000001 (1x10¯¹²) farad (pfd).

Piezoelectric Effect Some materials become electrically polarized when they are mechanically strained, the direction and magnitude of the polarization depends upon the nature, amount, and the direction of the strain. In such materials the reverse is also true in that a strain results from the application of an electric field.

PILC Cable Paper insulated, lead covered cable. Dry and wet locations - 85°C.

Pin An electrical terminal, smaller than a lug. Typically found in a connector.

Pipeline Tracer Wire (PTW) Suitable for direct burial with or within plastic pipe to facilitate the detection and tracing of underground piping systems.

Pitch (See lay).

Pitch Diameter The diameter of a circle passing through the center of the conductors in any layer of a multi-conductor cable.

PL Two rubber insulated, parallel-laid lamp cords with overall cotton or rayon braid. For light duty on small appliances in dry locations. 300V.

Planetary Twister A twisting machine whose payoff spools are mounted in rotating cradles that hold the axis of the spool in a fixed direction as the spools are revolved about one another so the wire will not kink as it is twisted.

Plastic Also called thermoplastic high polymeric substances, including both natural and synthetic products, but excluding the rubbers, that are capable of flowing under heat and pressure at one time or another.

Plasticizer A chemical agent added in compounding plastics to make them softer and more flexible.

Plater Wire Bare copper used as a hanger in electro-plating industry.

Plating The application of one metal over another.

PLSJ All rubber, parallel jacketed, two-conductor, light duty cord for pendant or portable use in damp locations. 300V.

PLT Same as PLSJ except: thermoplastic insulation.

PNA, PNR, PNW Polyethylene insulated control cables with nylon sheath on individual conductors. Cabled, taped, with polyvinyl chloride jacket. Dry or wet locations. 600V, 75°C.

PO Two stranded copper conductors with separator and code ribber insulation and cotton braid over each. Laid parallel with cotton or rayon braid overall. For use in dry location on small appliances. 300V-600V.

Polar Ingredient Any ingredient in a material or complex capable of ionization.

Polybutadiene A type of synthetic rubber often blended with other synthetic rubbers to improve their properties.

Polychoropene Chemical name for Neoprene. A rubber-like compound used for jacketing where wire and cable will be subject to rough usage, moisture, oil, greases, solvents and chemicals. May also be used as low voltage insulating material.

Polyethylene (wire insulation) A family of insulating materials derived from polymerization of ethylene gas. They are bascially pure hydrocarbon resins, with excellent dielectric properties.

Polymer A material having molecules of high molecular weight formed by polymerization of lower molecular weight molecules.

Polypropylene A thermoplastic similar to polyethylene but stiffer and having a higher softening point (temperature).

Polyurethane Broad class of polymers noted for good abrasion and solvent resistance. Can be in solid or cellular form.

Polyvinyl Chloride A general-purpose low voltage thermoplastic used for wire and cable insulations and jackets.

Portable Power Cable Flexible, all rubber insulated for hard usage. Some cables have shielded conductors (metallic or non-metallic) and can have neoprene sheath overall.

POSJ All rubber, parallel, light duty ripcord for use on lamps and small appliances. 300V, 60°C.

POSJX All rubber, parallel, #20 AWG ripcord for use on lamps, clocks and Christmas trees.

POT Thermoplastic, parallel, light duty ripcord. 300V, 60°C to 105°C.

Potting The sealing of a cable termination or other component with a liquid, which thermosets into an elastomer or solid compound to exclude moisture.

Power The amount of work per unit of time. Usually expressed in watts, and equal to I²R.

Power Factor The ratio of the power to the effective values of the electromotive force multiplied by the effective value of current in volts and amperes, respectively. The cosine of the angle between voltage applied and the current resulting.

Power Loss The difference between the total power delivered to a circuit, cable, or device, and the power delivered by that device to a load.

Power Ratio The ratio of the power appearing at the load, to the input power. Expressed in db, it is equal to 10 log10 (P2/P1), where P1 is input power and P2 is the power at the load.

Power Transformer Designed to transfer electrical power from the primary circuit to the secondary circuit(s) to

1) step up the secondary voltage at less current or

2) step down the secondary voltage at more current with the voltage-current product being constant for either primary or secondary.

POXT Same as POT except: #20 AWG for clock and Christmas tree use. 125V.

PPC Personal protecive clothing.

PPE Personal protective clothing.

PPE Portable power cable. Extra hard usage. 1-6 conductor.

Pressure Cable A cable having a pressurized fluid (gas or oil) as part of the insulation.

Primary Insulation The layer of material designed to do the electrical insulating, usually the first layer of material applied over the conductor for cables 2,000V and below.

Propagation Constant A complex quantity characteristic of a radio frequency transmission line that indicates the efffect of the line on the transmitted wave. The real part indicates the attenuation and the imaginary part the phase shift.

PS Thermostat cable with solid conductors, individual rubber insulation and cotton braid. Twisted, rubber jacket and cotton braid overall.

PTFE (TFE Teflon®) Polytetrafluoroethylene.

Pulling Eye A device that may be fastened to the conductor or conductors of a cable or formed by or fastened to the wire armor and to which a hook or rope may be directly attached in order to pull the cable into or through a duct.

Pulse A current or voltage that changes abruptly from one value to another and back to the original value in a finite length of time. Used to describe one particular variation in a series of wave motions.

Push Back That property of a braid or shield that allows the braid or shield to be pushed back along the cable core easily.

Put-Up The packaged product that is ready to be shipped.

PVC Polyvinyl chloride.

PVDF (Kynar®) Pennwalt trademark for polyvinylidene fluoride.

PW Moisture-proof, reinforced, portable cord with two or more rubber insulated conductors with individual cotton braid. Moisture-resistant cotton braid, rubber jacket. 300V-600V.


Quad A four-wire unit of insulated conductors. See Star Quad.


R Code rubber insulated building wire. 600V, 60°C.

R Symbol for resistance or resistor.

Radio Frequency The frequencies in the electromagnetic spectrum that are used for radio communications.

Rated Voltage The maximum voltage at which an electrical component can operate for extended periods without undue degradation or safety hazard.

RD Rubber insulated twin conductors, fibrous covered.

RDL Rubber insulated twin conductors, lead covered.

REA (Rural Electrification Administration) A federally supported program to provide electrical utilities in rural areas.

Reactance That part of the impedance of an alternating current circuit that is due to capacitance or inductance.

Reactance Drop With AC: the component of the voltage drop that is in quadrature with the current; it equals the current multiplied by the reactance between two points.

Redraw The drawing of wire that has already been drawn to an intermediate size, through a series of dies, to reach a desired wire size.

Reflection The change in direction, or return, of waves striking a surface. For example, electromagnetic energy reflections can occur at an impedance mismatch in a transmission line, causing standing waves.

Reflection Loss That part of a signal that is lost due to reflection of power at a line discontinuity.

Reinforced Sheath The outermost coverings of a cable that has a cable sheath constructed in layers with a reinforcing material, usually a braided fiber, placed between layers.

Relative Capacitance The ratio of a material's capacitance to that of a vacuum of the same configuration; will vary with frequency and temperature; also known as SIC (Specific Inductive Capacitance). An excellent indicator of chemical or physical changes of materials.

Reliability The probability that a device will function without failure over a specified time period or amount of usage.

Resistance The property of an electric circuit that determines for a given current the rate at which electric energy is converted into heat.

Resistivity (P) A material characteristic opposing the flow of energy through the material, expressed as a constant for each material. P is affected by temper, temperature, contamination, alloying, coating, etc.

Resonance An AC circuit condition in which inductive and capacitive reactance interact to cause a minimum or maximum circuit impedance.

Retractile Cable A cable that returns by its own stored energy from an extended to its original contracted form.

Retractile Cord Cord having specially treated insulation or jacket so that it will retract like a spring. Retractability may be added to all or part of a cord's length.

RF Fixture wire, code or latex rubber insulation and braid over solid or stranded conductor. 60°C.

RF Radio frequency.

RFH Same as RF except: rubber or latex rubber insulation heat-resistant. 75°C.

RG/U RG is the military designation for coaxial cable, and U stands for general utility.

RH Rubber insulated, heat resistant building wire. 600V. Dry and damp locations - 75°. (Some XLPE insulations can be RH rated).

RHD Rubber insulated, twin conductor, heat-resistant, fibrous covered wire.

RHDL Same as RHD except: lead instead of fibrous covered.

RHH Same as RH except: 90°C.

RHL Same as RHH except: with lead sheath overall.

RHM Rubber insulated multiple conductors, heat-resistant and overall fibrous covered.

RHML Same as RHM except: with lead cover overall.

RHW Rubber insulated building wire, heat and moisture-resistant. 600V. Dry and wet locations - 75°C.

RHW-2 Same as RHW except: 90°C.

RHWN Moisture and heat-resistant rubber insulation with neoprene jacket for use in ducts. 600V. Dry and wet locations - 75°C. Also NRHW.

Ribbon Cable A flat cable of individually insulated conductors lying parallel and held together by means of adhesive or woven textile yarn.

Ridge Marker One or more ridges running laterally along the outer surface of a plastic insulated wire for purposes of identification.

Rip Cord Two or more insulated conductors in a parallel configuration that may be easily separated leaving the insulation of each conductor intact.

RJ Rubber insulated cable and jute covered cable.

RJFJ Rubber insulated cable with flat band armor.

RJIJ Rubber insulated cable with interlock armor.

RL Rubber insulated cable with lead sheath.

RLJFJ Rubber insulated cable with lead, jute, flat band armor and overall jute covering.

RLJWJ Rubber insulated cable with lead, jute, steel wire armor and overall jute covering.

RM Rubber insulated multiple conductors with fibrous covering.

RML Same as RM except: lead instead of fibrous covering.

RMS Root-mean-square.

Rockwell Hardness A measure of hardness determined by resistance to indentation by a small diamond or steel ball under pressure.

Romex® Non-metallic sheath cable.

Root Mean Square The effective value of an alternating periodic voltage or current.

Rope Strand A conductor composed of a center group of twisted strands surrounded by one or more layers of similar groups of twisted strands.

Round Wire A wire circular in cross section as opposed to flat, square, etc.

RP Performance grade rubber insulation. 60°C.

RR (See USE).

RS Integral rubber insulation and jacket on single conductor cables.

RU Rubber insulated, latex building wire. 60°C.

Rubber (Wire Insulation) A general term used to describe wire insulations made of elastomer such as natural or synthetic rubbers, neoprene, butyl rubber, etc.

RUH Same as RI except: heat-resistant. 75°C.

Rupture The point at which a material physically comes apart as opposed to yield strength, elongation, etc.

RUW Same as RU except: moisture-resistant. 60°C.

RW Rubber insulated building wire. Moisture-resistant. 60°C.

RWS Same as RW except: synthetic rubber.


S Heavy duty, thermoset insulated portable cord. Stranded copper conductors with separator and individual rubber insulation. Two or more color-coded conductors cabled with filler, wrapped with separator and rubber jacketed overall. 600V.

SA Silicone rubber insulation, glass braid. 600V. Dry and damp locations - 90°C. Special applications - 200°C.

SAE Society of Automotive Engineers.

Safety Isolation Transformer Inserted to provide a non-grounded power supply such that a ground or neutral currents on the supply side will not pass through to the load side.

SB Slow burning wire. Three cotton braids, impregnated. 90°C.

SBR Rubber copolymer of styrene and butadiene. Also GR-S or Buna-S. Most commonly used type of synthetic rubber.

SC, SCE, SCT Portable stage and lighting flexible power cable. Extra hard usage.

Schering Bridge (See bridge).

SCPE Semi-conducting polyethylene.

SCT Semi-conducting tape.

SCXLPE Semi-conducting cross-linked polyethylene.

SD Service drop cable.

SDN Small diameter multi-conductor control cable with neoprene jacket and nylon sheath over polyethylene insulation.

SDT/TC Thermoplastic 90°C tray cable.

SE Above ground service entrance cable, not protected against mechanical abuse. Flame-retardant, moisture-resistant coating. Overall neoprene sheath. 60°C-75°C.

SE, SEO, SEOO Hard service cords. Thermoplastic insulation. Oil resistant.

SEA Service entrance cable, steel-armored under outer braid, one or two rubber insulated conductors with neutral conductor served concentrically, moisture-resistant tape, weatherproof braid finish. 300V, 75°C.

Semicon (Semi-conductor) Insulator that has impedance that provides protection by restricting longitudinal and tangential voltage stress on the cable surface adjacent to miscellaneous ground points to below what is necessary for corona production. Usually made of synthetic polymers.

Semi-Rigid A cable containing a flexible inner core and a relatively inflexible sheathing material, such as a metallic tube, but which can be bent for coiling or spooling and placing in a duct or cable run.

Separable Insulated Connector An insulated device to facilitate power cable connections and separations.

Separator A layer of insulating material such as textile, paper, Mylar®, etc. which is placed between a conductor and its dielectric, between a cable jacket and the components it covers, or between various components of a multiple-conductor cable. It can improve stripping qualities, flexibility, and offer additional mechanical and electrical protection to the components it separates.

SER Cable Triplex cable with all conductors insulated.

Series Circuit A circuit in which the components are arranged end to end to form a single path for current.

Series Resistance Any sum of resistances installed in sequential order within one circuit.

Serve Any filament or group of filaments, such as wire or fibers helically wound around a central core.

Service Drop Cable connecting utility supply and customer premises.

1) Single bare conductors on insulators

2) Insulated conductors combined with bare neutral in an integral assembly - bare neutral may act as messenger or assembly may be installed underground.

SEU Same as SEA except: not armored.

SEW, SEWF Silicone rubber insulated equipment wire (CSA).

SF Silicone rubber insulated fixture wire, solid or 7-strand conductor. 200°C.

SFF Same as SF except: flexible stranding. 150°C.

SG Same as SW except: with ground wires (CSA).

Sg. Specific gravity.

SGO Same as SWO except: with ground wires (CSA).

SH-A Portable mine power cable, three or four individually shielded conductors. 5,000V.

SH-B Same as SH-A except: shield is overall.

SH-C Same as SH-B except: with grounding conductors.

SH-D Same as SH-A except: with grounding conductors.

SHD-GC Same as SH-D except: with ground check monitoring. For supply to mobile equipment.

Sheath (See jacket).

SHFS Polyvinyl insulated with felted asbestos, flameproof cotton or rayon braid. Navy switchboard wire. 600V.

Shield (See shielding).

Shield Coverage (See shield percentage).

Shield Effectiveness The relative ability of a shield to screen out undesirable radiation. Frequently confused with the term shield percentage.

Shield Percentage The physical area of a circuit or cable actually covered by shielding material, expressed in percent.

Shielding The practice of confining the dielectric field to the inside of the cable insulation or insulated conductor assembly by surrounding the insulation or assembly with a grounded conducting medium. There are two types of shields: metallic and non-metallic.

Shovel Cable Normally SHD-GC type for high voltage 5-25kV power supply to mobile equipment.

Shunt A device used to divert part of an electric current.

SIC (Specific Inductive Capacitance) (See relative capacitance).

Siemens Inverse of resistance (1/0hm). Also referred to as Mho.

Signal An electric current used to convery information either in digital, analog, audio, or video.

Silicone A material made from silicon and oxygen. Can be in thermosetting elastomer or liquid form. The thermosetting elastomer form is noted for high heat resistance.

SIS Switchboard wire, single conductor, thermosetting insulation, flame-retardant. 600V, 90°C.

SJ, SJE, SJEO, SJEOO Junior hard service cords. 18-10 AWG sizes, rubber insulated pendant or portable cord. Same construction as type S, but 300V. Jacket thickness different.

SJO Same as SJ except: neoprene, oil-resistant compound outer jacket. Can also be made water-resistant. 300V, 60°C.

SJOO Same as SJO except: with oil-resistant insulation as well as oil-resistant jacket.

SJT Junior hard service thermoplastic or rubber insulated conductors with overall thermoplastic jacket. 300V, 60°C to 105°C.

SJTO Same as SJT except: oil-resistant insulation.

SJTOO Same as SJTO except: with oil-resistant insulation.

Skin Effect The tendency of alternating current, as its frequency increases, to travel only on the surface of a conductor.

Skived Tape Tape shaved in a thin layer from a cylindrical block of material.

SL Single conductor paper lead cables twisted together, without overall covering (same as ML).

SNM Shielded non-metallic sheathed cable.

SO Extra-hard service cord, same construction as type S except: with oil-resistant insulation.

SOO Same as SO except: with oil-resistant insulation.

SOW Water-resistant neoprene jacketed portable cord (CSA).

SP-1 All thermoset, parallel jacketed, two-conductor light duty cord for pendant or portable use in damp locations. 300V.

SP-2 Same as SP-1 except: heavier construction, with or without third conductor for grounding purposes. 300V.

SP-3 Same as SP-2 except: heavier construction for refrigerators or room air conditioners. 300V.

Spacer Cable Weatherproof Line Wire held by insulated spacers.

Spark Test A test to locate pinholes in an insulated wire by application of an electrical potential across the material for a very short period of time while the wire is drawn through an electrode field.

SPC Submersible pump cable.

SPE-1 All thermoplastic elastomer, parallel jacketed, two-conductor light duty cord for pendant or portable use in damp locations. 300V.

SPE-2 Same as SPE-1 except: heavier construction, with or without third conductor for grounding purposes. 300V.

SPE-3 Same as SPE-2 except: heavier construction for refrigerators or room air conditioners.

Specific Gravity The ratio of the weight of any volume of substance to a weight of an equal volume of some substance taken as a standard, usually water for liquids and hydrogen for gases.

Specific Inductive Capacitance (See relative capacitance).

Spectrum Frequencies or radiations that exist in a continuous range and have a common characteristic. A spectrum may be inclusive of many spectrums, e.g., the electromagnetic radiation spectrum includes the light spectrum, radio spectrum, infrared spectrum, etc.

Spiral Wrap The helical wrap of a tape or thread over a core.

Sprinkler Control Cable Multi-conductor cable assembly, moisture and chemical resistant. For use as control cable for irrigation systems.

SPT-1 All thermoplastic, parallel jacketed, two-conductor light duty cord for pendant or portable use in damp locations. 300V.

SPT-2 Same as SPT-1 except: heavier construction. 300V. With or without third conductor for grounding.

SPT-3 Same as SPT-2 except: heavier construction for refrigerators or room air conditioners. 300V.

Square Mil The area of a square one mil by one mil.

Squirrel Cage Motor An induction motor having the primary winding, usually the stator, connected to the power and a current is induced in the secondary cage winding, usually the rotor.

SR Silicone rubber control cable. 600V, 125°C.

SR-AW Flexible, nickel-plated copper conductor, silicone rubber insulation, glass braid. 600V, 200°C.

SR-C Solid copper conductor, silicone rubber insulation, glass braid. 600V, 125°C.

SRD Thermoset portable range or dryer cable.

SRDE Thermoplastic elastomer portable range or dryer cable.

SRDT Thermoplastic portable range or dryer cable.

ST Extra-hard service cord, jacketed, same as S except: all thermoplastic construction. 600V, 60°C to 105°C.

Standing Wave The stationary pattern of waves produced by two waves of the same frequency traveling in opposite directions on the same transmission line. The existence of voltage and current maxima and minima along a transmission line is a result of reflected energy from an impedance mismatch.

Standing Wave Ratio (SWR) A ratio of the maximum amplitude of a standing wave stated in current or voltage amplitudes.

Star Connection Interconnection of three electrical equipment windings in star (wye) fashion.

Static Charge An electrical charge that is bound to an object. An unmoving electrical charge.

Statistical Analysis Distribution A statistical method used to analyze data by correlating data to a theoretical curve to:

a) test validity of data

b) predict performance at conditions different from those used to produce the data. The normal distribution curve is most common.

Stay Cord A component of a cable, usually a high tensile textile, used to anchor the cable ends at their points of termination and to keep any pull on the cable from being transferred to the electrical connections.

STO Same as ST except: with oil-resistant thermoplastic outer jacket. 600V, 60°C.

STOO Same as STO except: with oil-resistant insulation.

Strain Gauge A device for determining the amount of strain (change in dimensions) when a stress is applied.

Strand One of the wires or groups of wires of any stranded conductor.

Strand Conductor Shield A layer of semi-conducting material or tape applied directly over the stranded conductor cables rated 2,000 volts and higher. This reduces the possibility of high stress point occurring between the conductor and insulation.

Strand Lay (See lay).

Stress Relief Cone Mechanical element to relieve the electrical stress at a shielded cable termination, used about 2 kV.

Submersible Pump Cable Twisted unjacketed, jacketed, flat webbed, or jacketed insulated conductors for use within the well casing to supply power to the submersible pump cable.

SUN RES Sunlight resistant.

Superconductors Materials whose resistane and magnetic permeability are infinitesimal at absolute zero (-273°C).

Suppressor A device used to reduce or eliminate unwanted actions in electric or electronic circuits. For example, a resistance conductor in, or a resistor in series with, a sparkplug cable, to suppress interference which would otherwise affect radio reception in and near the vehicle.

Surface Resistivity The ratio of the potential gradient parallel to the current along its surface to the current per unit width of the surface, usually expressed in ohms. Note: Surface resistivity of a material is numerically equal to the surface resistance between two electrode forming opposite sides of a square, the square size being immaterial.

Surge A temporary and relatively large increase in the voltage or current in an electric circuit or cable. Also called transient.

SV Vacuum cleaner cord, two or three-conductor, thermoset included. Overall thermoset jacket. For light duty in damp locations. 300V, 60°C.

SVE Same as SV except: thermoplastic elastomer insulation and jacket.

SVEO Same as SVE except: oil resistant jacket.

SVEOO Same as SVEO except: oil resistant insulation.

SVO Same as SV except: oil resistant thermoset jacket. 300V, 60°C.

SVOO Same as SVO except: oil resistant insulation.

SW Thermoset jacketed power supply cable (8 AWG to 2 AWG) (CSA). 600V.

Swamp The condition that prevails when too large a signal is applied to an electronic device, resulting in distortion of the output from the device.

Sweep-Test Checking frequency responseby generating an RF voltage whose frequency is varied back and forth through a given frequency range at a rapid constant rate and observing the results on an oscilloscope. A high structural return loss is desirable.

Switchboard Cable Multi-core telephone cables used for the internal wiring of telephone exchanges.

Switchboard Wire Chemically cross-linked polyethylene or asbestos insulated wire, resistant to heat, flame and corrosive vapor. (See SIS, TA, and TBS).

SWO Same as SW except: neoprene jacketed (CSA).

SWT Plastic jacketed power supply cable (8 AWG to 2 AWG) (CSA) 600V.

Synchronous Machine A machine in which the average speed of normal operation is exactly proportional to the frequency of the electrical system to which it is connected.

Synchronous Speed The speed of rotation of the magnetic flux produced by linking the primary winding.

Synchrotron A device for accelerating charged particles to high energies in a vacuum. The particles are guided by a changing magnetic field while they are accelerated in a closed path.


T Thermoplastic vinyl, building wire. 600V, 60°C.

TA Switchboard wire, thermoplastic and asbestos insulation. 600V, 90°C.

TAA Flexible nickel or nickel-clad copper, Teflon tape, felted asbestos, asbestos braid. 600V, 200°C.

TAGT Stranded nickel-clad copper covered with Teflon, felted asbestos and fiberglass impregnated with Teflon. 600V, 250°C.

Tank Test A voltage dielectric test where the specimen to be tested is submerged in liquid (usually water) and a voltage applied between the conductor and the liquid as ground.

Tape Wrap A spirally or longitudinally applied tape material wrapped around the wire, either insulated or uninsulated, used as an insulation or mechanical barrier.

Tarnish A discolored or stained conductor or shield wire caused by exposure to the atmosphere or by heat.

TBS Switchboard wire, single conductor, thermoplastic insulation. 600V, 90°C. Flame-retarding with fibrous outer braid.

TBWP Three cotton braids, weatherproof saturated. No voltage rating.

TC Tray cable with flame-retardant jacket - per NEC article 340.

Tear Test A test to determine the tear strength of an insulating material.

Teck Armor See Metal Clad. Has special recognition and application per CSA.

Tefzel® (ETFE) Dupont Company trademark for ethylene tetrafluoroethylene.

Teflon® (ETFE) DuPont Company trademark for fluorocarbon resins. (See FEP and TFE).

Temperature Coefficient of Resistivity The amount of resistance change of a material per degree of temperature rise.

Temperature Rating The maximum temperature at which the insulating material may be used in continuous operation without loss of its basic properties.

Temperature Stress The maximum stress which can be applied to a material at a given temperature without physical deformation.

Tensile Strength The greatest longitudinal tensile stress a substance can bear without tearing apart or rupturing.

Tensile Stress Force per unit cross sectional area applied to elongate a material.

Tension Set The condition when a plastic material shows permanent deformation, caused by a stress, after the stress is removed.

TEW Appliance wires, solid or stranded single conductor, plastic insulated. 600V, 105°C. (CSA)

TF Fixture wire, thermoplastic covered solid or 7 strands. 60°C.

TFE Polytetrafluoroethylene. Only for leads within apparatus or within raceways connected to apparatus. 600V. Dry locations - 250°C.

TFF Same as TF except: flexible stranding. 60°C.

TFFN Same as TFF except: with nylon sheath.

TG Flexible nickel or nickel-clad copper conductor, Teflon tape, glass braid. 200°C.

TGS Solid or flexible copper, nickel-clad iron or copper, or nickel conductor. Teflon tape, silicone glass braid. 600V. 250°C.

Thermal Aging Exposure to a given thermal condition or a programmed series of thermal conditions for prescribed periods of time.

Thermal Alloying The act of uniting two different metals to make one common metal by the use of heat.

Thermal Expansion The expansion of a material when subjected to heat.

Thermal Rating The temperature range in which a material will perform its function without undue degradation.

Thermal Resistance

1) Change in the electrical resistance of a material when subjected to heat.

2) Resistance to heat flow from conductors to outer surface of insulation or sheath in a wire or cable.

Thermal Resistivity Thermal resistance of a unit cube of material.

Thermocouple Two joined metals, usually joined wires. A temperature difference between the junctions generates a voltage that can be calibrated to indicate temperature.

Thermocouple Lead Wire Similar to thermocouple wire except the degree of accuracy in temperature measurements is not as high and it is used to transmit thermocouple information to remote indicators.

Thermocouple Wire A two-conductor cable, each conductor employing a dissimilar metal, made up specifically for temperature measurements.

Thermoelectric Generator A device that converts thermal energy to electricity by direct interaction of a heat flow and the charge carriers in an electric circuit, and that requires, for this process, the existence of a temperature difference in the electric circuit.

Thermoelectric Heat Pump A device that transfers thermal energy from one body to another by the direct interaction of an electrical current and the heat flow.

Thermoplastic Insulation that will soften and distort from its formed shape by heating above a critical temperature particular to the material.

Thermoplastic Elastomer Used for insulation and jacketing compound for portable cords with the following U.L. designations: SE, SEO, SRDE, SPE, SJE, SJEO.

Thermosetting Insulation that will not soften or distort from its formed shape by heating until a destructive temperature is reached.

THHN Polyvinyl chloride insulated building wire, nylon jacketed. 600V. Dry and damp locations - 90°C.

THHW Polyvinyl chloride insulated building wire. 600V. Wet locations - 75°C. Dry locations - 90°C.

Thompson Effect The absorption or evolution of thermal energy produced by the interaction of an electric current and a temperature gradient in a homogeneous electric conductor.

Thumper A device used to locate faults in a cable by the release of power surges from a capacitor, characterized by the audible noise where the cable breaks down.

THW Polyvinyl chloride insulated building wire. Flame-retardant. All sizes carry the VW-1 Flame rating. Dry and wet locations - 600V, 75°C. Special applications within electric discharge lighting equipment - 1,000V, 90°C.

THWN Same as THW except: reduced insulation wall thickness and nylon jacket overall. 600V. Dry and wet locations - 75°C.

Tinned Wire Copper wire that has been coated with a layer of tin or solder to simplify soldering.

Tinsel Wire A very flexible conductor made by serving one or more very small flat conductors over a fibrous core such as high tenacity rayon, nylon, or cotton fibers.

Torque Test A test to determine the stiffness of a material under given environmental conditions.

TP Parallel tinsel cord. All thermoplastic insulation over two extremely flexible conductors. Light duty, attached to appliances of 50W or less. For use in damp locations in lengths of eight feet or less. (See TS).

TPE Thermoplastic elastomer. (See Elexar® and TPR).

TPO Same construction as type PO but with extra flexible tinsel conductors. 125V.

TPR® (TPE) UniRoyal trademark for thermoplastic elastomer.

TPT Same as TP except: thermoplastic jacket. 125V.

Tracer Stripe Color-coding stripe: the first, or widest, stripe is the base stripe; the other, usually narrower stripes are tracer stripes.

Transducer A device for transforming mechanical energy to electrical energy, or for transforming electrical energy to mechanical energy, such as in microphones and loudspeakers, but not motors or generators.

Transfer Switch A device for transferring one or more load conductor connections from one power source to another.

Transformer A static device consisting of winding(s) with or without a tap(s) with or without a magnetic core for introducing mutual coupling by induction between circuits.

Transformer Riser Wire Similar qualities and performance as Weatherproof Line Wire.

Transmission Line An arrangement of two or more conductors or a waveguide used to transfer signal energy from one location to another.

Tray Cable A multi-conductor cable having a nonmetallic jacket, designed for use in cable trays. Most Tray Cable is type TC. (See TC).

Tree Wire See Weatherproof Line Wire.

TRHDPE Track-resistant high-density polyethylene.

TRHMPE Track-resistant high molecular polyethylene.

Triaxial A cable with three coincident axes, such as, conductor, first shield, and second shield insulated from one another.

Triboelectric Noise Noise generated in a shielded cable due to variations in capacitance between shielding and conductor as the cable is flexed.

Triplex Cable Three single conductor cables twisted together with or without an overall covering.

Trolley Coach & Motor Lead Extra flexible stranded copper conductor rubber-insulated reinforced braid and heavy neoprene jacket for connecting overhead power supply via trolley to motor control panels in buses, transit cars and mine equipment. 600V.

Trolley Wire Bronze Same as Trolley Wire except: made from solid bronze in the configuration of: round, grooved, or figure 9.

Trolley Wire Copper Single conductor, solid copper, having a hard drawn temper, made in the configuration of: round, grooved, figure 8, or figure 9. Trolley wire is used as an overhead power source for electric railroad locomotives, cranes, light rail transit systems, and underground mining motorcars.

True Concentric A true concentric stranding or twisted cable is when each successive layer has a reversed direction of lay from the preceding layer.

Trunk Cable (See feeder cable).

TR-XLPE Tree retardant, covered with cross-linked polyethylene.

TS Two or three-conductor thermoset insulated and jacketed tinsel cord. Light duty, attached to an appliance of 50W or less. For use in damp places in lengths of eight feet or less. (See TP).

TSO Same as TS except: with oil resistant jacket.

TST Same as TS except: thermoplastic insulation and jacket.

TT Polyvinyl chloride insulation and sheath, aerial and duct.

TW Polyvinyl chloride insulated building wire. 600V. Dry damp locations  - 60°C.

Twin Coaxial Two separate, complete coaxial cables laid parallel or twisted around each other in one complex.

Twin-Lead A transmission line having two parallel conductors separated by insulating material. Line impedance is determined by the diameter and spacing of the conductors and the insulating material and is usually 300 ohms for television receiving antennas. Also called balanced transmission line and twin-line.


U-Bend Test A test to determine corona discharge and ozone resistance of a mechanically stressed insulation material. Time to failure is the parameter measured.

UF Thermoplastic underground feeder and branch circuit cable. 600V. Single conductor - 60°. Multi-conductor - 75°.

UHF Ultrahigh frequency, the band extending from 300 to 3,000 MHz as designated by the Federal Communications Commission.

UL Underwriters Laboratories Inc.

Ultrasonic Cleaning Immersion cleaning aided by ultrasonic waves that causes micro-cavitations.

Ultrasonic Detector A device that detects the ultrasonic noise such as that produced by corona or leaking gas.

Ultraviolet Radiant energy within the wavelength range of 10 to 380 nanometers. Ultraviolet light will degrade some polymers.

Ultraviolet Degradation The degradation caused by long time exposure of a material to sunlight or other ultraviolet rays.

Unbalanced Line A transmission line in which voltages on the two conductors are unequal with respect to ground, e.g., a coaxial cable.

Unidirectional Concentric Stranding Each successive stranding layer has a different lay length thereby retaining a circular form without migration of strands from one layer to another.

Unidirectional Stranding All layers of a stranded conductor have the same direction of lay.

Unilay More than one layer of helically laid wires with the direction of lay and length of lay the same for all layers.

Unilay Stranding A bunched construction having 19,27,37 or any number of strands that might be found in a concentric stranding.

URC Weatherproof wire.

URD Underground rural distribution.

USE Underground service entrance cable. 600V. 75°C.

USE-2 Same as USE except: 90°C.


V Varnished-cambric insulation with fibrous covering.

V Volt.

VA Volt-ampere. A designation of power in terms of volts and amperes.

VCB Varnished-cambric insulation, cotton braid, flame retarding, moisture-resistant finish.

VCL Varnished-cambric insulation, lead covered cable. Ends must be hermetically sealed.

VD Indicates a twin wire having two type V conductors laid parallel under an outer fibrous covering.

VDE Varnished-cambric insulation, lead covered cable. Ends must be hermetically sealed.

VDE Verband der Elektrotechnik Organisationen.

Velocity of Propagation The transmission speed of an electrical signal down a length of cable compared to speed in free space. Expressed as a percentage of speed in free space. (A function of dielectric constant).

VG Varnished glass tape over a flexible copper conductor. Varnished glass or nylon braid. 600V or 3,000V, 130°C.

VHF Very high frequency, the band extending from 30 to 300 mHz as designated by the Federal Communications Commission.

Video Pertaining to picture signals in a television system.

Viscosity Internal friction or resistance to flow of a liquid, the constant ratio of shearing stress to rate of shear.

Viscous A thick liquid, resistant to flow.

VLF Very low frequency, the band extending from 10 to 30 kHz as designated by the Federal Communications Commission.

VM Indicates a cable having two or more type V conductors twisted together under an outer fibrous covering.

Volt A unit of electromotive force.

Voltage Electrical potential or electromotive force expressed in volts.

Voltage Divider A network consisting of impedance elements connected in series to which a voltage is applied and from which one or more voltages can be obtained across any portion of the network.

Voltage Drop Amount of voltage loss from source to point of measurement in a conductor of given size, conductor material, and length.

Voltage Rated Welding Cable Certified insulation voltage protection. To protect against welder primary voltage leaking to welding leads.

Voltage Rating The highest voltage that may be continuously applied to an insulated conductor in conformance with standards or specifications.

Voltage Standing Wave Ratio The ratio of the maximum effective voltage to the minimum effective voltage measured along the length of a mismatched radio frequency transmission line.

Voltage Stress The stress found within a material when subjected to an electrical charge.

Voltage to Ground The voltage between an energized conductor and earth.

Volume Resistivity Resistance between two electrodes of unit area and unit distance apart that are in contact with, or imbedded in, a specimen. The ratio of the direct voltage applied to the electrodes to the current between them distributed through the volume of the specimen. Express in ohms/centimeter.

Vulcanization A chemical reaction in which the physical properties of an elastomer are changed by reacting with sulfur or other cross-linking agents.

VW-1 A UL rating given single conductor cables as to flame-resistant properties, formerly FR-1.


W Symbol for watt or wattage.

W Thermoset insulation and jacket. Heavy-duty portable power cable, one to six conductors without grounds. 600V.

W/G With ground.

W/SHLD Wire shield.

Wall Thickness Thickness of a layer of applied insulation or jacket.

Water Absorption Test A method to determine the water absorbed through an insulating material after a given water immersion period.

Waterblocked Cable Cable constructed with no internal voids in order to prevent migration of water. Also, a cable with water swellable powder or tape that prevents migration of water.

Watertight Cable A cable specially constructed with no internal voids in order to allow no longitudinal water passage under a given pressure.

Watt A unit of electrical power; the power of one ampere of current pushed by one volt of electromotive force.

Wave Front

1) That part of an impulse, in time or distance, between the 10% point and the point at which the impulse reaches 90% of crest value in a conductor

2) The rising part of an impulse wave.

Waveform A graphical representation of a varying quantity. Usually time is represented on the horizontal axis, and the current or voltage value is represented on the vertical axis.

Wavelength The distance, measured in the direction of propagation, of a repetitive electrical pulse or waveform between two successive points that are characterized by the same phase of vibration.

Waveshape Representation The designation of current or voltage by a combination of two numbers. For other than rectangular impulses:

1) virtual duration of the wave front in microseconds and

2) time in microseconds from virtual zero to the instant at which 1/2 of the crest value is reached on the tail.

For rectangular impulses:

1) minimum value of current or voltage and

2) duration in microseconds.

Weatherproof Line Wire Copper conductor, solid or stranded, soft (annealed), medium hard, or hard drawn, covered with black high molecular weight polyethylene (HMWPE). For use in overhead distribution systems where protection from environmental elements is required. Designed to withstand temporary surface to ground discharge of tree limb contact. (Also called Tree Wire or Spacer Cable).

Weibull Distribution (See statistical analysis distribution).

Wetting The ability of a material to absorb moisture.

Wheatstone Bridge (See bridge).

Wicking The longitudinal flow of a liquid in a wire or cable construction due to capillary action.

Wire Wire is a slender rod or filament of drawn metal, usually copper or aluminum. If a wire is covered with insulation, it is called an "insulated wire". The term "wire" really referes to the metal, the insulation is normally included in the context.

Wire Type Designations Letters and numbers assembled to designate material and capabilities of wire and cable as defined in the NEC are spread throughout this glossary. The following suffixes or prefixes may be added to further describe material and capabilities. For example:

XHHW/LS - Same as XHHW except: with limited smoke characteristics.

Fr - Flame retardant

H - Heat-rated

LC - Limited corrosivity

LS - Limited smoke

LS-ZH - Low Smoke Zero Halogen

LT - Limited toxicity

N - Nylon

P - Polypropylene

PE - Polyethylene

R - Rubber

S - Silicone

TP - Thermoplastic

TS - Thermosetting

VW-1 - Flame rating

W - Weather rated

XLPE - Cross-linked polyethylene

ZH - Zero halogen (meets LC, LS, LT)

Wire Type Designations Letters assembled to designate material and capabilities of wire and cable as defined in IEEE 1580 are shown below:

E - Ehylene propylene rubber

P - Cross-linked polyolefin

S - Silicone

T - Polyvinyl chloride

T/N - Polyvinyl chloride insulation with nylon jacket

X - Cross-linked polyethylene.

Wiring Diagram Assembly of lines and component symbols with connecting dots that shows how devices are interconnected.

WP Weatherproof construction, two or three impregnated cotton braids. 80°C.


X Symbol for reactance.

X Two FX wires twisted together, color-coded. 125V, 60°C.

XHH Cross-linked polyethylene building wire. 600V. Dry and damp locations - 90°C.

XHHW Cross-linked polyethylene building wire. 600V. Dry and damp locations - 90°C. Wet locations - 75°C.

XHHW-2 Same as XHHW except: dry and wet locations - 90°C.

XLPE Cross-linked polyethylene.

X-Ray Penetrating short wavelength electromagnetic radiation created by electron bombardment in high voltage apparatus; produce ionization when they strike certain materials.


Yield Strength The minimum stress at which a material will start to physically deform without further increase in load.


Z Modified ethylene tetrafluoroethylene. 600V. Dam locations - 90°C. Dry locations - 150°C.

Z Symbol for impedance.

Zetabond® DOW chemical trademark for metal plastic laminate sheath suitable for electrostatic shield, surface discharge path, moisture barrier, and chemical barrier.

ZW Same as Z except: Wet location - 75°C.