Term

Definition

Quad-Rated Wire

The name for 90°C and 105°C wire which replaces four other types of wire - CSA TEW 105°C; 90°C MTW 600V; 90°C AWM 1000V; and 105°C AWM 600V.

Quadruplex Cable

A cable composed of four conductors twisted together, usually three insulated and a bare neutral.

Quarter-Phase or Two-Phase

A term characterizing a combination of two circuits energized by alternating voltage sources which differ in phase by a quarter of a cycle, 90 degrees.

R

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

R.M.S.

(Root Means Square) Used as an A.C. value of voltage or current. Expressed for example as 120 volts AC RMS.

Rated Voltage

That maximum voltage at which an electrical component can operate for extended periods without undue degradation of safety hazard.

Rating

The rating of an electrical device includes (1) the normal r.m.s. current which it is designed to carry, (2) the normal r.m.s. voltage of the circuit in which it is intended to operate, (3) the normal frequency of the current and the interruption (or withstand) rating of the device.

RCDD

(Registered Communications Distribution Designer) - Professional certification granted by BICSI.

RD

Rubber-insulated twin conductors, fibrous covered.

RDL

Rubber-insulated twin conductors, lead covered.

Reactance

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

Reactive Factor

The ratio of the reactive volt-amperes to the apparent power.

Reactive or Quadrature Componenet

That component of the current which is quadrature, or 90 degees out of phase, with the voltage across the circuit.

Reactive Volt Amperes

The product of the voltage, current and the sine of the phase difference between them. Expressed in vars.

Receiver

Portion of a photoelectric sensor that contains a photo sensor.

Receptacle

A contact device which is intended to establish electrical connection with an inserted plug.

Redraw

The consecutive drawing of wire through a series of dies to each a desired wire size.

Reel

A revolvable flanged device made of wood and/or metal which is used for winding flexible metal wire or cable.

Reflection Loss

That part of a signal which is lost due to reflection of power at a line discontinuity.

Reinforced Sheath

The outermost covering of a cable that has a cable sheath constructed in layers with a reinforcing material, usually a braided fiber, molded in place between layers.

Rejection Fuse

A current-limiting fuse with high interrupting rating and with unique dimensions or mounting provisions.

Rejection Fuse Block

A fuse block designed to accept fuses of a specific class.

Relay

A device which is operative by variation in the conditions of one electric circuit to effect the operation of other devices in the same or another electric circuit.

Release Point

The point at which a sensor returns to its original state as the target leaves the sensing field. Also called "reset point."

Renewable Fuse

An enclosed fuse the body of which can be opened and the fusible link replaced for re-sue. This fuse usually does not have a filter.

Repeat Accuracy

The measure of variation in operating distance between succussive operations under constant operating conditions. The measurement is often expressed as a maximum percentage of the "operating distance." (NOTE: The target must also remain within the sensing field long enough to allow the load sufficient time to respond to the output signal of the sensor.

Resilient

The property of a substance to return to its original configuration after release of an applied force.

Resistance

The property of an electric circuit which determines for a given current the rate at which electric energy is converted into heat and has a value such that the current squared multiplied by the resistance gives the power converted.

Resistive Conductor

A conductor used for its high electric resistance characteristics.

Resistive Load

A device which opposes the flow of electric current. There is a voltage drop across a resistive load, which causes the device to dissapate heat.

Response Time

Time it takes for an output of a photoelectric sensor to respond to an input signal.

Response Time

The length of time required for an output of a transducer to rise to a specific percentage of its final value as a result of a step change in input.

Retroreflective

Detection method where light from the emitter is aimed at, and reflected back to the receiver, from a retroreflective target.

Return Loss

Noise or interference cause by impedance of a cable expressed in decibels.

Reverse Polarity Protection

Internal circuitry that protects a device from being ruined if proper polarity of voltages is not maintained when wiring the device.

RF

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

RFH

Same as RF, but rubber or latex rubber insulation heat-resistant. 75°C

RFI

(Radio Frequency Interference) Electrical Noise

RH

Rubber-insulated, heat resistant building wire. 75°C

RH/RW

Rubber-insulated, heat and moisture resistant building wire. 75°C dry, 60°C wet.

RHD

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

RHDL

Same as RHD, except lead instead of fibrous covered.

Rheostat

An adjustable resistor constructed so that its resistance may be changed without opening the circuit.

RHH

Rubber-insulated, heat-resistant building wire. 90°C

RHL

Same as RHH, but with lead sheath overall.

RHM

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

RHML

Same as RHM, but with lead cover overall.

RHW

Rubber-insulated building wire, heat and moisture-resistant. 75°C dry or wet.

Ribbon Cable

A cable consisting of two or more conductors laid parallel in one plane and held in place by some means.

Ring

One of the two conductors or cable pair in a telephone circuit.

Riser

The conduit path between floors of a building.

RJ

Rubber-insulated and jute covered cable.

RJ (Registered Jack)

Telephone and data jack applications registered with FCC.

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 overing.

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, but lead instead of fibrous covering.

Rocker Switch

A switch that is operated by a paddle type actuator such as a decorator switch.

Rod

The solid round metallic form of copper and aluminum which is the most effective shape from which to draw wire.

Romex

Non-Metallic Sheath Cable

Root Mean Square

The effective value of an alternating periodic voltage or current.

Root-Mean Square or Effective Value

The square root of the mean of the squares of the instantaneous values for one complete cycle. It is usually abbreviated r.m.s. Unless otherwise specified, the numerical value of an alternating current refers to its r.m.s. value. The r.m.s. value of a sinusoidal wave is equal to its maximum, or peak value, divided by square root of 2

Rope Strand

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

Rope-Lay Cable

A concentric stranded cable designed for flexibility with its individual members made up of strands which are either concentric stranded or bunched.

Rotary Dimming

Is acheived through the rotation of a knob of any style to control the lighting level components.

Rotary Phase Converter

Converts an alternating current system of one or more phases to alternating current system of a different number of phases, but of the same frequency.

Round Strand

A conductor composed of a center group of twisted strands surrounded by one or more layers of similiar 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.

RPM

Revolutions Per Minute.

RR

Rubber insulation, neoprene jacket. See type USE

RS

Integral rubber insulation and jacket on single conductor cables.

RTS

Reverse twist secondary.

RU

Rubber-insulated, latex building wire. 60°C

RUH

Same as RU, but heat-resistant. 75°C

Rupture

In the breaking strength or tensile strength tests the point at which a material physically comes apart as opposed to yield strength, elongation, etc.

RUW

Same as RU, but moisture-resistant. 60°C

RW

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

RWS

Same as RW, but synthetic rubber.

S

Heavy duty, rubber-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, asbestos or glass braid, for use in dry locations. Maximum operating temperature for special applications, 125°C.

Sag (conductor)

The vertical distance between a suspended conductor and an imaginary straight-line connecting the points of suspension. Sag may be measured at the mid point between the suspensions, the lowest point of the conductor or at any specified point.

SB

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

SBR

Rubber co-polymer of styrene and butadiene.

SCR

Silicon Controlled Rectifier. Semiconductor used in AC two-wire devices to provide voltage to the device and to switch in-line loads.

Screw Extruder

A machine which accpets solid particles (pellot or powder) or liquid (molten) feed; melts and conveys it through a surrounding barrell by means of a rotating screw and pumps it, under pressure, through a die.

SD

Service drop cable. Two code-rubber-insulated conductors, tape, laid parallel with neutral conductor concentric turnover. Tape and braid overall. Also round construction.

SDC

Self Damping Conductors

SDN

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

SDT/TC

Thermo plastic 90°C tray cable.

SE

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

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

Sealed Gauge Pressure (PSIS)

A measure of pressure reference to atmospheric pressure.

Secondary

The windings which receive the energy by induction from the primary.

Sectional Wall Plate

Individual section wall plates with different openings that can be field assembled into a custom multi-gang wall plate.

Sector Cable

A multicore cable in which the cross section of each conductor is substantially a section of a circle, an ellipse (oval), or a figure intermediate between them; when cabled, contributes to a smaller overall diameter.

Self-Supporting Cable

Made with a steel support strand capable of supporting its own weight across spans.

Semi-Conducting

A non-conducting material made slightly conducting by the addition of a conducting material such as carbon.

Semiconductor Fuse

An extremely fast-acting fuse intended for the protection of power semiconductors. Sometimes referred to as a rectifier use.

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.

Sensing Distance

The maximum distance at which under specifications, a photoelectric sensor can detect a target.

Sensing Range

The maximum operating range at which the sensor will reliably detect a standard target under conditions of nominal voltage and temperature.

Sensor

A device that detects, and then responds to an external stimulus or change.

Series

An adapter wired in series to a fexible cord containing an in-line switch which is used to control electrical equipment plugged into the adaptor.

Series Resistance

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

Serve

Any filament or group of filaments, such as wires or fibres helically wound around a central core.

Service Factor Amps

This is the amount of current the motor will draw when it is subjected to a percentage of overload equal to the service factor on the nameplate of the motor. For example, many motors will have a service factor of 1.15, meaning that the motor can handle a 15% overload. The service factor amperage is the amount of current that the motor will draw under the service factor load condition.

Service Loop

The slack which should be left in the cable at the communications outlet to accommodate future needs.

SEU

Same as SEA, but not armored.

SEW,SEWF

Silicone Rubber insulated equipment wire (C.S.A.).

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 (C.S.A.).

SG

Specific Gravity

SGO

Same as SWO except with ground wires (C.S.A.).

SH-A

Portable mine power cable, three or four individually shielded conductors. 5000V

SH-B

Same as SH-A, except shield is overall.

SH-C

Same as SH-B, but with grounding conductors.

SH-D

Same as SH-A, but with grounding conductors.

Sheath

The material, usually an extruded plastic or elastomer, applied outermost to a wire or cable. Very often referred to as a jacket.

SHFS

Polyvinyl-insulated with felted-asbestos, flame-proof cotton or rayon braid. Navy switch-board wire. 600V

Shield

In cables, that metallic layer applied over the dielectric or group of dielectrics, composed of woven braided, or served wires, foil wrap or tubular metallic construction to prevent elecrostatic or electromagnetic interference between the enclosed wires and external fields.

Shielded Cable

Usually concerning a high voltage power cable 5000V and above enclosed in a non-magnetic conducting envelope, so constructed that substantially every point on the insulation is at ground potential or some pre-determined potential with respect to the ground. Can apply to multiple conductor cable in which each single conductor is shielded or to a multiple conductor cable where the overall assembly is shielded.

Short Circuit

Loads which occur during fault conditions and are characterized by very heavy current flow.

Short Circuit

Can be classified as an overcurrent which exceeds the normal full load current of a circuit. Also characteristic of this type of overcurrent is that it does not leave the normal current carrying path of the circuit-that is, it flows from the source through the conductors, through the load, back through the conductors, to the source again.

Short Circuit Protection

Internal circuitry which protects the photoelectric sensor in the event that the load becomes shorted.

Short Circuit Rating

The maximum short circuit current of an electrical component can sustain without the occurence of excessive damage when protected with an overcurrent protective device.

Short-Time Rating

The maximum constant load that can be carried for a apecified time without exceeding established temperature rise limitations under prescribed conditions.

A device used to divert part of an electric current.

SIC

Specific inductive capacity. Same as dialectric constant.

Signal

An electric current used to convey information either digital, analog, audio, or video.

Signal Conditioning

To process the form or mode of a signal so as to make it electrically compatible with a given device.

Single Mode Fiber

An optical fiber which allows only one mode to propogate and which is generally used for long distance telephone transmission.

Single Phasing

That condition which occurs when one phase of a three phase system opens, either in a low voltage (secondary) or high voltage (primary) distribution system. Primary or secondary single phasing can be caused by any number of events. This condition results in unbalanced currents in polyphase motors and unless protective measures are taken, causes overheating and failure.

Single Pole Switch

(single-pole single-throw) A switch that makes or breaks the connection of one conductor and controls one load from one location.

Single Receptacle

A receptacle that accepts only one plug.

Single Weave

A wire mesh grip woven with single strands of wire material

Single-phase circuit

An AC circuit consisting of two or three intentionally interrelated conductors.

Sinter

To thermally cure or treat a material.

SIS

Indicates single conductor having synthetic thermosetting insulation of heat-resistant, moisture-resistant, flame-retardant grade. Also made with chemically cross linked polyethylene insulation. Used for switchboard wiring only 90°C.

Six-Phase

A term characterizing the combination of six circuits energized by alternating e.m.f.'s which differ in phase by one-sixth of a cycle; i.e. 60 degrees.

SJ

Junior hard service, rubber-insulated pendant or portable cord. Same construction as type S, but 300V. Jacket thickness different.

SJO

Same as SJ, but neoprene, oi-resistant compound outer jacket. Can also be made "water-resistant." 300V, 60°C

SJOO

Same as SJO but with oil-resistant insulation as well as an 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 but oil-resistant thermoplastic outer jacket. 60°C

SJTOO

Same as SJTO but with oil-resistant insulation.

Skin Effect

In an alternating current system, a phenomenon that occurs at increased frequencies causing an increase in resistance of the conductor leaving the outer skin to carry most of the current. The phenomenon increases in intensity the higher the frequency.

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)

Slant Symbol

(/) As used in wiring device ratings, indicates that two or more voltage potentials can be used.

Sleet-Proof

Apparatus is designated as sleet-proof when so constructed or protected that the accumulation of sleet will not interfere with its successful operations.

Slide Dimming

Is achieved through the linear movement up and down or horizontal of a slide mechanism to control the lighting level.

Slide Switch

A switch having a sliding actuating member which makes or breaks the sitch contact mechanism.

Slimline-Single Pin

A fluorescent lampholder having a single pin contact and accepting fluroescent lamps of the T-8 or T-12 types, 1" or 1 1/2" in diameter and in a smaller version the T-6 type, 3/4" in diameter.

Slip

Slip is used in two forms. One is the slip RPM which is the difference between the synchronous speed and the full load speed. When this slip RPM is expressed as a percentage of the synchronous speed, then it is called percent slip or just "slip." Most standard motors run with a full load slip of 2% to 5%.

Snap-In Lampholder

A special type of incandescent lampholder supplied with assembled side spring clips which snap into a hole cut in a flat panel, securing the lampholder in place without additional fastening means.

SNM

Shielded non-metallic sheathed cable.

SO

Hard service cord, same construction as type S except oil-resistant neoprene jacket. 600V, 60°C to 90°C

Solid Conductor

A solid conductor is a conductor consisting of a single wire.

Solid State

A device, circuit or system whose operation is dependent upon any combination of optical, electrical, or magnetic phenomena within a solid. Generally referred to as having an infinite life and no moving parts.

SOO

Same as SO but with oil-resistant insulation.

SOW

Water resistant neoprene jacketed portable cord (C.S.A.).

SP-1

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

SP-2

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

SP-3

Same as SP-2, but heavier construction for refrigerators or room air conditioners. 300V

Spacer Cable

A distribution cable designed to be used in conjunction with insulating spacers which maintain conductor spacing in overhead line installations. This cable is considered uninsulated and installed likewise, but the covering on the conductors does allow for conductor close proximity and reduce faults due to the touching of tree limbs.

Span (Full-Scale Output for FSO)

The algebraic difference in the electrical output when the maximum and minimum pressure is applied to the input.

Spark Test

A test designed to locate pin-holes 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.

Special Purpose Fuses

Fuses with special performance characteristics or rating intended to protect equipment or components under specified conditions.

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 gas.

Spiral Wrap

A term given to describe the helical wrap of a tape or thread over a core.

Splash-Proof

An open apparatus in which the ventilation openings are so constructed that drops of liquid or solid particles coming toward it at any angle up to 100° downward from vertical cannot enter directly or by running along a surface.

Split Circuit

A duplex receptacle that can be wired for two separate circuits.

Split Mesh

A wire mesh grip separated at one row along the wire mesh axis utilizing an additional lace or rods to weave closed around cable.

SPT-1

Same as SP-1, except all-thermoplastic. 300V. With or without 3rd conductor for grounding.

SPT-2

Same as SP-2, except all-thermoplastic. 300V. With or without 3rd conductor for grounding.

SPT-3

Same as SP-3, except all-thermoplastic. 300V. With or without 3rd conductor for grounding.

Square Mil

The area of a square one mil by one mil.

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

Portable range or dryer cable. Three or four rubber-insulated conductors with rubber or neoprene jacket, flat or round construction. 300V, 60°C

SRDT

Same as SRD, except all-thermoplastic with a maximum temperature of 90°C.

SR-H

Silicone rubber-insulated, asbestos braid. 500V, 125°C

ST

Hard service cord, jacketed, same as type S except all-plastic construction. 600V, 60°C to 105°C

Stability

The output state of the photoelectric is either stably ON, ustable, or stably OFF. Unstable outputs cause the system to perform irratically. Unstable output occurs when the amount of light incident on the receiver is near the trigger level of the device.

Stability

The ability of a transducer to maintain all of its performance specifications throughout its life.

Standard Target

An object used to determine sensing range. This is normally a square mild steel plate 1mm thick with the length of each side equal to the diameter of the sensing face or 3 times the nominal sensing distance of the sensor.

Star Wiring

Called Star Topology and Home Run, a method of cabling each telecommunications outlet directly to the horizontal cross-connect in the telecommunications closet with an individual pair of cables.

Starting Torque

The amount of torque the motor produces when it is energized at full voltage and with the shaft locked in place. This value is frequently expressed as "locked rotor torque." It is the amount of torque available when powere is applied to break the load away and start accelerating it up to speed.

STO

Same as ST but with oil-resistant thermoplastic outer jacket. 600V, 60°C to 105°C

STOO

Same as STO but with oil-resistant insulation.

Straight Blade

A plug, connector, receptacle, flanged inlet or flanged outlet providing no locking features.

Strain Relief Grip

A wire mesh grip used to relieve strain or stress at the transition point between relatively flexible cable or conduit and the rigid connection point.

Strand

A single unisulated wire.

Strand Lay

The distance of advance of one strand of a spirally stranded conductor, in one turn, measured axially.

Stranded

A number of solid wires twisted together to form a flexible conductor.

Stranded Conductor

A stranded conductor is a conductor composed of a group of wires, or of any combination of groups of wires.

Strap Dimmer/Fan Speed Control

Any dimmer or fan speed control that will fit into a traditional NEMA standard switch box, without and external heat sink.

Submersible

Apparatus is designated as submersible when so constructed that it operates successfully in water under specified

Supply Voltage

The nominal voltage, or voltage range, at which the photoelectric sensor is designed to be operated continuously.

Support Grip

A wire mesh grip used for permanent or temporary support of a length of cable.

Suppressed Voltage

The amount of voltage allowed to pass through a surge suppression device to the equipment connected to the device.

Suppressed Voltage Rating

Determinedd by UL when specific current and voltage is applied to a surge suppression device. For permanent devices UL tests at 3000A, 6000V while portable devices are tested at 500A, 6000V.

Surface Lampholder

A lampholder of any type intended for mounting on a flat or plane surface.

Surface Mounted

A device intended to be installed on the surface a wall, panel, or equipment.

Surface Resistivity

The surface resistivity of a material is 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 electrodes forming opposite sides of a square, the square size being immaterial.)

Surge-Supression

The use of a device containing electronic components which limits peak voltage to a pre determined value when voltage spikes or surges appear on the connected line.

SV

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

SVO

Same as SV except neoprene jacket. 300V, 60°C

SVT

Same as SV except all-plastic construction. With or without third conductor for grounding purposes only. 300V, 60°C to 90°C

SVTO

Same as SVT except with oil-resistant thermoplastic jacket. 60°C

SW

Rubber jacketed power supply cable (8AWG to 2AWG) C.S.A. 600 Volt.

Switch

A device for making, breaking or changing the connections in an electric circuit.

Switch

A device for making breaking or changing the connections in an electric circuit.

Switchboard Wire

Chemically cross-linked polyethylene or asbestos insulated wire resistant to heat, flame, and corrosive vapor.

SWO

Same as SW except neoprene jacketed (C.S.A.).

SWT

Plastic jacketed power supply cable (8AWG to 2AWG) 600V (C.S.A.).

Synchronous Converter or Rotary Converter

Converts an alternating current to a direct current.

Synchronous Motor

An alternating current motor which operates at the speed of rotation of the magnetic flux.

Synchrounous Speed

This is the speed at which the magnetic field within the motor is rotating. It is also approximately the speed that the motor will run under no load conditions. For example, a 4 pole motor running on 60 cycles would have a magnetic field speed of 1800 RPM. The no load speed of that motor shaft would be very close to 1800 RPM. The difference between the synchronous speed and the full load speed is called the slip RPM of the motor.

T

Thermoplastic vinyl, building wire. 60°C

TA

Switchboard wire, thermoplastic and asbestos insulation. 90°C

TAA

Flexible nickel or nickel-clad copper, teflon tape, felted asbestos, asbestos braid. 200°C

Take-Up

The process of accumulating wire or cable onto a reel, bobbin, or some other type of package. Also refers to the device utilized for pulling wire or cable through a piece of equipment or machine.

Tamper Resistant

A receptacle which by its construction limits improper access to its energized contacts.

Tandem

A wall plate in which individual gangs are arranged vertically one above the other.

Tank Test

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

Tape Wrap

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

Target

The object to be detected.

Tarnish

A term used to describe a discolored or stained conductor or shield wire caused by exposure to the atmosphere.

TAS

Shielded thermoplastic appliance wire.

TBS

Switchboard wire, thermoplastic insulation, flame-proof cotton braid. 600V, 90°C

TBWP

Three cotton braids, weatherproof saturated. No voltage rating.

TC

Tray cable Art 340 NEC

Tear Test

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

Temperature Coefficient of Resistivity

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

Temperature Stress

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

Tensile Strength

A term denoting the greatest longitudinal tensile stress a substance can bear without tearing apart or rupturing.

Tensile Stress

Torce per unit cross-sectional area applied to elongate a material.

Tension Set

The condition when a plastic material show permanent deformation cause by stress, after the stress is removed.

Terminal

A terminal is a fixed location on a wiring device where a conductor is intended to be connected.

Test Reports

The permanent records made by a wire manufacturer of the test performed on a batch of wire to a specification.

TEW

Canadian Standards Association type appliance wires. Solid or stranded single conductor, plastic-insulated. 600V, 105°C

TF

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

TFE

Teflon (tetrafluoroethylene)

TFF

Same as TF but flexible standing. 60°C

TFFN

Same as TFF but 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 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 Effect on Span

The error defined by the change in sensitivity due to a change in ambient temperature within the compensated temperature range.

Thermal Effect on Zero

The error defined by the maximum deviations from the zero due to changes in ambient temperature, within the compensated temperature range and no pressure applied.

Thermal element

A metallic or nonmetallic fusible material that is part of a thermal cutoff and is responsive to temperature by a change of state at the temperature for which it is calibrated.

Thermal Expansion

The expansion of a material when subjected to heat.

Thermal Rating

The maximum and/or minimum temperature at which a material will perform its function without undue degradation.

Thermal Resistance

That change in the electrical resistance of a material when subjected to heat. 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.

Thermal Shock

The resulting characteristics when a material is subjected to rapid and wide range changes in temperature in an effort to discover its ability to withstand heat and cold.

Thermal-Magnetic Circuit Breaker

A circuit breaker which has the overcurrent and tripping means of the thermal type, the mangetic type or a combination of both.

Thermocouple

A device consisting of two metals usually in wire form joined in two places. If a temperature difference exists between the junctions, a voltage is generated which 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.

Thermoplastic

Insulation that will resoften and distort from its formed shape by heating above a critical temperature peculiar 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

Term describing insulation that will not resoften or distort from its formed shape by heating until a destructive temperature is reached.

Thermostat

An automatic control actuated by temperature change to maintain temperatures between predetermined limits.

THHN

90°C 600V nylon jacketed building wire

Three Postition Center "OFF"

A two circuit, three position switch either the maintained or momentary type, in which the OFF position is indicated by the centered postion of the actuator.

Three-phase circuit

A combination of circuits energized by AC that differ in phase by one-third of a cycle, that is, 120 degrees.

Three-phase transformer

A combination in one unit of three single-phase transformers with separate electric circuits, but having certain magnetic circuits in common. There are three magnetic circuits through the core, and the fluxes in the various circuits are displaced in phase.

Three-Way Switch

(single pole double throw) A switch which is used in pairs to control one load from two or more locations.

Threshold Current

The symmetrical RMS available current at the threshhold of the current-limiting range when tested to the industry standard. This value can be read off of a peak let-through chart where the fuse curve intersects the A-B line. A threshold ratio is the relationship of the threshold current to the fuse's continous current rating.

THW

Thermoplastic vinyl insulated building wire. Flame-retardant, moisture and heat-resistant. 75°C. Dry and wet locations.

THWN

Same as THW but with nylon jacket overall. 75°C

TIA

(Telecommunications Inudstry Association) Industry trade association which works with the Electronics Industry Association (EIA) in developing standards.

Time Delay

A period of time when a load is energized or de-energized. At the end of the desired time period the load changes state (i.e. on or off).

Time Delay Fuse

A fuse which will carry an overcurrent of a specified magnitude for a minimum specified time without opening, as defined in the tri-national Fuse Standard 248.

Time Rating

Most motors are rated for continous duty whch means that they can operate at full load torque continuously without overheating. Motors used on certain types of applications such as waste disposal, valve actuators, hoists, and other types of intermittent loads, will frequently be rated for short term duty such as 5 minutes, 15 minutes, 30 minutes, or 1 hour. Just like a human being, a motor can be asked to handle very strenous work as long as it is not required on a continuous basis.

Time Switch

An electronic or electro-mechanical control, used to schedule "turn on" and "turn off" time based on the time of day.

Timer

An electronic or electro-mechanical control used to produce a time delay to control a load.

Tinning

Tinning is divided into two types: Electrotinned and Hot Dipped. Electrotinned is the process of electroplating the surface of a conductor material with a tin or tin-lead alloy.

Tinsel Wire

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

Tip

The positive conductor of a pair in a basic telephone circuit. The tip is grounded.

Toggle Dimming

Is achieved through up or down toggling of traditional switch style toggle used to control the dimming components.

Toggle Switch

A switch having a levertype actuating member which makes or breaks the switch contacts when its position is changed.

Topology

The pysical or geometric configuration of a local area network.

Toroid Choke

An electronic component constructed of a ferrite ring wrapped with copper wire, used to reduce RFI generated by an electronic switching device.

Torque

the twisting force exerted by the shaft of a motor. Torque is measured in pound inches, pound feet, and on small motors, in terms of ounce inches.

Torque Test

A test designed to ascetain the stiffness of a material under given environmental conditions.

Totally Enclosed

Apparatus with an integral enclosure so constructed that, while not airtight, the enclosed air has no deliberate connection with external air except for draining and breathing.

Touch Dimming

The ability of a dimmer to control lighting levels by sensing the touch of a hand to its sensor plate.

TP

Parallel tinsel cord. All-rubber insulation and jacket over two extremely flexible conductors. Light duty, attached to appliances of 50W or less. For use in damp locations in lenghts of eight feet or less.

TPE

Thermoplastic Elastomer

TPO

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

TPT

Same as TP but all-thermoplastic insulation and jacket. 125V

Tracer Stripe

When more than one color coding stripe is required, the first, or widest, stripe is the base stripe, the other, usually narrower stripes, being termed tracer stripes.

Transformer

A device for transferring energy in an alternating current system from one circuit to another, consisting of two independent electric circuits linked by a common magnetic circuit.

Transparent

Targets that permit transmission of essentially all incident light.

Tree Wire

A cable designed to be used in conjunction with insulators, for overhead distribution, having heavy covering which reduces faults due to the touching of tree limbs in heavily wooded areas. (See spacer cable, sometimes one in the same).

TRIAC

(Bidirectional Triode Thyristor) A solid state output device capable of switching alternating current.

Triaxial

A cable construction, having three coincident axis, such as conductor, first shield and second shield all insulated from one another.

Triplex Cable

A cable composed of either three insulated single-conductor cables twisted together or two insulated single-conductor cables twisted together with a bare conductor or messenger.

True Concentric

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

TS

Two or three-conductor rubber-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.

TSO

Same as type TS but with neoprene jacket. 125V

TST

Same as TS, but all-thermoplastic insulation and jacket.

TT

Polyvinyl chloride insulation and sheath, aerial and duct.

Turnkey

An Installation in which the user receives a complete operatioanl system ready to be used.

TVSS

Transient Voltage Surge Suppressor

TW

Thermoplastic vinyl-jacketed building wire, moisture-resistant. 60°C

Twin Cable

A cable consisting of two insulated conductors laid parallel and having a common covering.

Twin Coaxial

A configuration containing two separate, complete coaxial cables laid parallel or twisted around each other in one complex.

Twin Wire

A cable composed of two small insulated conductors laid parallel and having a common covering.

Twisted Pair

A cable composed of two small insulated conductors twisted together, but having no common covering.

Twisted Pair

Two insulated copper wires twisted together to reduce interference from each other.

Twisted Pair Cable

A type of interconnection cable consisting of pairs of wire twisted together.