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Glossary of Electrical Terms

electrical-terms-glossary ©Copyright
Summary: Glossary of Electrical Wiring Terms and Definitions for Devices used for Home Electrical Wiring.


Basic Electrical Terms for Home Electrical Wiring


General Electrical Terms
Adapter Variations
Cord Connectors
Flanged Inlets
Flanged Outlets
Fluorescent Starters
Lamp holders
Plugs
Receptacles
Surge Suppression
Switches
Wall plates




General Electrical Terms

Adapter

An accessory used for interconnecting non-mating devices or converting an existing device for modified use.

Ballast

A transformer that steps down AC line voltage to voltage that can be used by fluorescent or other types of lighting. Ballasts may be electromagnetic or electronic

Cord Connector

A portable receptacle designed for attachment to or provided with flexible cord, not intended for fixed mounting.

Flanged Inlet

A plug intended for flush mounting on appliances or equipment to provide a means for power connection via a cord connector.

Flanged Outlet

A receptacle intended for flush mounting on appliances or equipment to provide a means for power connection via an inserted plug.

Fluorescent Starter

A device with a voltage-sensitive switch and a capacitor that provides a high-voltage pulse to start a fluorescent lamp. Rated in watts.

Lamp holder

A device with contacts that establishes mechanical and electrical connection to an inserted lamp.

Plug

A device with male contacts intended for insertion into a receptacle to establish electrical connection between the attached flexible cord and the conductors connected to the receptacle.

Receptacle

A device with female contacts designed for fixed installation in a structure or piece of equipment and which is intended to establish electrical connection with an inserted plug.

Switch

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

Wall plate

A plate designed to enclose an electrical box, with or without a device installed within the box.


Adapter Variations


Cube Tap

An adapter that converts one receptacle opening into multiple openings.

Current Tap

An adapter designed for medium base lamp holders which has one or two receptacle openings. Available with or without integral switch.

Duplex

An adapter that provides two female receptacle openings when plugged into a single receptacle opening.

Grounding

An adapter that converts a two-wire receptacle opening into a two-pole, three-wire grounding receptacle opening.

Lamp holder

A threaded adapter that converts the thread size of the lamp holder in which it is inserted so that the lamp holder can accept an incandescent lamp bulb of a different size thread.

Molded-On

An adapter that is factory molded to a length of flexible cord.

Series

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

"Y" Type

An adapter in the form of a letter "Y", having two cord connectors on one end and a male plug on the other end.

"W" Type

Same as "Y" type, except having three cord connectors arranged in the form of the letter "W".


Cord Connectors

Angle

A connector that allows the attached flexible cord to exit at right angles.

Corrosion Resistant

A connector constructed of special materials and/or suitably plated metal parts that is designed to withstand corrosive environments. Corrosion resistant devices must pass the ASTM B117-13 five-hundred hour Salt Spray (Fog) Test with no visible corrosion.

Dust Proof

A connector designed so that dust will not interfere with its operation. The IP Suitability Rating designates the degree of protection a device offers against the ingress of foreign objects (e.g. IP 20).

Explosion Proof

A connector constructed to meet the requirements of hazardous locations as defined by the National Electrical Code, NFPA-70.

Hospital Grade

A connector designed to meet the performance requirements of high-abuse areas typically found in health care facilities. These connectors are tested to the Hospital Grade requirements of Underwriters Laboratories Inc. Standard 498.

Locking

A connector designed to lock an inserted plug with a matching blade configuration when the plug is rotated in a clockwise direction. The plug can only be removed by first turning it in a counter-clockwise direction.

Midget

A connector designed with a smaller body diameter than standard connectors with a similar rating.

Molded On

A connector that is factory molded to a length of flexible cord.

Pin and Sleeve

A connector with hollow, cylindrical sleeve-type contacts.

Straight Blade

A non-locking connector into which mating plugs are inserted at a right angle to the plane of the connector face.

Weatherproof

A connector specially constructed so that exposure to weather will not interfere with its operation.


Flanged Inlets

Corrosion Resistant

An inlet constructed of special materials and/or suitably plated metal parts that is designed to withstand corrosive environments. Corrosion resistant devices must pass the ASTM B117-13 five-hundred hour Salt Spray (Fog) Test with no visible corrosion.

Flush-Mounted

An inlet intended to be installed flush with the surface of a panel or a piece of equipment.

Locking

An inlet designed to lock an inserted matching connector when the connector is rotated in a clockwise direction. The connector can only be removed by first turning it in a counter-clockwise direction.

Midget

An inlet designed with a smaller body diameter than standard connectors with a similar rating.

Pin and Sleeve

An inlet with round pin-type contacts intended to mate with a connector having hollow cylindrical female contacts.

Straight Blade

A non-locking inlet into which mating connectors are inserted at a right angle to the plane of the connector face.

Surface-Mounted

An inlet designed to be surface mounted on a panel or piece of equipment.

Watertight

An inlet specially constructed so that water will not enter under specified test conditions. The IP Suitability Rating designates the degree of protection a device offers against the ingress of moisture and water (e.g. IP 55, IP 44).

Weatherproof

An inlet specially constructed to protect it from the effects of weather in outdoor locations.


Flanged Outlets

Corrosion Resistant

An outlet constructed of special materials and/or suitably plated metal parts that is designed to withstand corrosive environments. Corrosion resistant devices must pass the ASTM B17-13 five-hundred hour Salt Spray (Fog) Test with no visible corrosion.

Flush-Mounted

An outlet intended to be installed flush with the surface of a panel or a piece of equipment.

Locking

An outlet designed to lock an inserted plug with a matching blade configuration when the plug is rotated in a clockwise direction. The plug can only be removed by first turning it in a counter-clockwise direction.

Midget

An outlet designed with a smaller body diameter than standard devices with a similar rating.

Pin and Sleeve

An outlet with hollow cylindrical female contacts intended to mate with a plug having round pin contacts.

Straight Blade

A non-locking outlet into which mating straight-blade plugs are inserted at a right angle to the plane of the outlet face.

Surface-Mounted

An outlet designed to be surface mounted on a panel or piece of equipment.

Watertight

An outlet specially constructed so that water will not enter under specified test conditions. The IP Suitability Rating designates the degree of protection a device offers against the ingress of moisture and water(e.g. IP 55, IP 44).

Weatherproof

An outlet specially constructed so that exposure to weather will not interfere with its operation.


Fluorescent Starters

Automatic Reset

A starter that automatically restarts a new replacement fluorescent lamp after the circuit is energized.

Direct Current

A thermal-type starter designed for use on direct current (DC) circuits.

Glow Discharge

A starter that provides a rapid lamp start-up and will continue to try to start a failed fluorescent lamp, causing the lamp to flicker until it is replaced.

Manual Reset

A starter that automatically deactivates a failed fluorescent lamp to eliminate flickering. A reset button provides a means of activating the circuit after lamp replacement.


Lamp holders

Bayonet

Designed for incandescent lamps having an unthreaded metal shell with two diametrically opposite key ways that mate with the key ways on the lamp holder. Pushing down on the bulb and turning it clockwise in the lamp holder locks the bulb in place.

Candelabra

A small screw-base threaded lamp holder designed for candelabra-base incandescent lamps commonly used in chandeliers, night lights, and ornamental lighting.

Circline

A four-contact, double-ended lamp holder designed for use with tubular, circular fluorescent lamps.

Compact Fluorescent

A lamp holder designed for the Compact Fluorescent Lamps (CFL’s) that are increasingly being used to replace incandescent lamps for energy efficiency.

Dimmer

An electronic device with either a round knob, slide lever or finger-tip controlled buttons used to dim/brighten incandescent lighting. Available in a variety of wattages; fluorescent version also available.

Double-Contact Recessed

Designed for high-output fluorescent lamps.

Edison Base

An internally-threaded lamp holder, with the inner shell approximately 1" in diameter. Designed for widely-used standard medium base lamps.

Electrolier

Similar to the Edison Medium Base lamp holder, but with a smaller outer diameter.

Incandescent

Designed for use with all manufactured incandescent lamps, most of which have threaded bases.

Intermediate

A lamp holder with a threaded screw shell designed for intermediate base lamps that have a 13/32" threaded base (smaller than the standard 1" diameter medium base). Mostly used in decorative lighting.

Key

A lamp holder with a flat or round "key" knob that operates an internal switching mechanism ("Keyless" lamp holders do not provide an internal switching mechanism).

Lumiline

A specially designed lamp holder for tubular Lumiline-type incandescent lamps, typically used in bathrooms and retail display cases.

Medium Base

Same as the Edison base lamp holder. An internally-threaded lamp holder, with the inner shell approximately 1" in diameter. Designed for widely-used standard medium base lamps.

Miniature

Designed for the smallest available incandescent lamps with a screw-in base, approximately 3/8" diameter Widely used in flashlights and toys, etc.

Mogul

The largest screw-in type lamp holder, designed for mogul incandescent lamps with a screw base of approximately 11/2" diameter Used in street lights and numerous commercial/industrial applications.

Medium Bi-Pin

A fluorescent lamp holder with two contacts, used in pairs. For type T-8 tubular fluorescent lamps, approximately 1" in diameter.

Miniature Bi-Pin

Similar to medium bi-pin lamp holders, but designed for type T-5 tubular fluorescent lamps, approximately 5/8" in diameter.

Outlet Box

Medium-base incandescent lamp holder designed for mounting in 31/4" or 4" electrical boxes. Available with or without pull-chain mechanism, and with or without built-in receptacle.

Pull-Chain

An incandescent lamp holder with an internal switching mechanism that is activated by pulling down on a beaded chain or cord.

Push-Through

An incandescent lamp holder with an insulated lever that is pushed from either side to activate an internal ON/OFF switching mechanism.

Slimline Single-Pin

A fluorescent lamp holder with a single contact designed for Slimline fluorescent lamps such as the T-12 (11/2" diameter), T-8 (1" diameter), and the smaller version T-6 (3/4" diameter).

Snap-In

An incandescent or compact fluorescent lamp holder with factory-assembled spring clips that securely snap into a panel cutout without requiring additional fasteners.

Surface-Mounted

A lamp holder of any type that mounts on a flat or plane surface.


Plugs

Angle

A plug that allows the attached flexible cord to exit at right angles.

Corrosion Resistant

A plug constructed of special materials and/or suitably plated metal parts that is designed to withstand corrosive environments. Corrosion resistant devices must pass the ASTM B117-13 five-hundred hour Salt Spray (Fog) Test with no visible corrosion.

Dust Proof

A plug designed so that dust will not interfere with its operation. The IP Suitability Rating designates the degree of protection a device offers against the ingress of foreign objects (e.g. IP 20).

Explosion Proof

A plug constructed to meet the requirements of hazardous locations as defined by the National Electrical Code, NFPA-70.

Hospital Grade

A plug designed to meet the performance requirements of high-abuse areas typically found in health care facilities. These plugs are tested to the Hospital Grade requirements of Underwriter's Laboratories Inc. Standard 498.

Locking

A plug designed to lock into a matching connector or receptacle configuration when the plug is rotated in a clockwise direction. The plug can only be removed by turning it in a counter-clockwise direction.

Midget

A plug designed with a smaller body diameter than standard plugs with a similar rating.

Molded On

A plug that is factory molded to a length of flexible cord.

Pin and Sleeve

A plug with round pin contacts.

Straight Blade

A non-locking plug that is inserted at a right angle to the plane of the matching device face.

Weatherproof

A plug specially constructed so that exposure to weather will not interfere with its operation.


Receptacles

AL/CU

30A, 50A or 60A receptacles designated for use with aluminum or copper circuit conductors, identified by "AL/CU" stamped on the device. Receptacles without this designation must never be used with aluminum circuit conductors.

Clock Hanger

A single, recessed receptacle with a specialized cover plate that provides a hook or other means of supporting a wall clock.

CO/ALR

15A or 20A receptacles designated for use with aluminum or copper circuit conductors, identified by "CO/ALR" stamped on the device. Receptacles without this designation must never be used with aluminum circuit conductors.

Corrosion Resistant

A receptacle constructed of special materials and/or suitably plated metal parts that is designed to withstand corrosive environments. Corrosion resistant devices must pass the ASTM B117-13 five-hundred hour Salt Spray (Fog) Test with no visible corrosion.

Display

Receptacle with a special cover plate intended for flush mounting on raised floors or walls.

Duplex

Two receptacles built with a common body and mounting means; accepts two plugs.

Dust Proof

A receptacle designed so that dust will not interfere with its operation. The IP Suitability Rating designates the degree of protection a device offers against the ingress of foreign objects (e.g. IP 20).

Explosion Proof

A receptacle constructed to meet the requirements of hazardous locations as defined by the National Electrical Code, NFPA-70.

Fan Hanger

A single receptacle with a specialized cover plate that provides a hook or other means of supporting a wall fan.

Four-In-One or "Quad"

A receptacle in a common housing that accepts up to four plugs. Four-In-One receptacles can be installed in place of duplex receptacles mounted in a single-gang box, providing a convenient means of adding receptacles without rewiring.

GFCI (Ground Fault Circuit Interrupter)

A receptacle with a built in circuit that will detect leakage current to ground on the load side of the device. When the GFCI detects leakage current to ground, it will interrupt power to the load side of the device, preventing a hazardous ground fault condition. GFCI receptacles must conform to UL Standard 943 Class A requirements, and their use is required by the National Electric Code NFPA-70 in a variety of indoor and outdoor locations.

Hospital Grade

A receptacle designed to meet the performance requirements of high-abuse areas typically found in health care facilities. These receptacles are tested to the Hospital Grade requirements of Underwriters Laboratories Inc. Standard 498.

Interchangeable

A receptacle or combination of receptacles with a common mounting dimension that may be installed on a single or multiple-opening mounting strap.

Isolated Ground

Receptacles intended for use in an Isolated Grounding system where the ground path is isolated from the facility grounding system. The grounding connection on these receptacles is isolated from the mounting strap.

Lighted (Illuminated)

A receptacle with a face that becomes illuminated when the device is connected to an energized electrical circuit.

Locking

A receptacle designed to lock an inserted plug with a matching blade configuration when the plug is rotated in a clockwise direction. The plug can only be removed by first turning it in a counter-clockwise direction.

Pin and Sleeve

A receptacle with cylindrical sleeve-type contacts.

Safety or Tamper-Resistant

A receptacle specially constructed so that access to its energized contacts is limited. Tamper-resistant receptacles are required by the National Electric Code NFPA-70 in specific pediatric care areas in health care facilities.

Single

A receptacle that accepts only one plug.

Snap-In

A receptacle with factory-assembled spring clips that securely snap into a panel cutout without requiring additional fasteners.

Split-Circuit

A duplex receptacle that allows each receptacle to be wired to separate circuits. Most duplex receptacles provide break-off tabs that allow them to be converted into split-circuit receptacles.

Straight Blade

A non-locking receptacle into which mating plugs are inserted at a right angle to the plane of the receptacle face.

Surface-Mounted

Any receptacle that mounts on a flat or plane surface.

Surge-Suppression

A receptacle with built-in circuitry designed to protect its load side from high-voltage transients and surges. The circuitry will limit transient voltage peaks to help protect sensitive electronic equipment such as PC’s, modems, audio/video equipment, etc.

Triplex

A receptacle with a common mounting means which accepts three plugs.

Weatherproof

A receptacle specially constructed so that exposure to weather will not interfere with its operation.


Switches

AC/DC

A switch designated for use with either Alternating Current (AC) or Direct Current (DC).

AC Only

A switch designated for use with Alternating Current (AC) only.

Dimmer

A switch with electronic circuitry that provides DIM/BRIGHT control of lighting loads.

Door

A momentary contact switch, usually installed on a doorjamb, that is activated when the door is opened or closed.

Double-Pole, Single-Throw (DPST)

A switch that makes or breaks the connection of two circuit conductors in a single branch circuit. This switch has four terminal screws and ON/OFF markings.

Double-Pole, Double-Throw (DPDT)

A switch that makes or breaks the connection of two conductors to two separate circuits. This switch has six terminal screws and is available in both momentary and maintained contact versions, and may also have a center OFF position.

Feed-Through

An in-line switch that can be attached at any point on a length of flexible cord to provide switching control of attached equipment.

Flush-Mounted

A switch designed for flush installation with the surface of a panel or equipment.

Four-Way

A switch used in conjunction with two 3-Way switches to control a single load (such as a light fixture) from three or more locations. This switch has four terminal screws and no ON/OFF marking.

Horsepower Rated

A switch with a marked horsepower rating, intended for use in switching motor loads.

Interchangeable

A switch or combination of switches with a common mounting dimension that may be installed on a single or multiple-opening mounting strap.

Lighted Handle

A switch with an integral lamp in its actuator (toggle, rocker or pushbutton) that illuminates when the switch is connected to an energized circuit and the actuator is in the OFF position.

Locking

A switch equipped with a locking mechanism that requires a key to operate the switching functions.

Low-Voltage

A switch rated for use on low-voltage circuits of 50 volts or less.

L-Rated

A switch specially designated with the letter "L" in its rating that is rated for controlling tungsten filament lamps on AC circuits only.

Maintained Contact

A switch where the actuator (toggle, rocker, pushbutton or key mechanism) makes and retains circuit contact when moved to the ON position. The contacts will only be opened when the actuator is manually moved to the OFF position. Ordinary light switches are maintained contact switches.

Manual Motor Controller

A switch designed for controlling small DC or AC motor loads, without overload protection.

Mercury

A type of switch that uses mercury as the contact means for making and breaking an electrical circuit.

Momentary Contact

A switch that makes circuit contact only as long as the actuator (toggle, rocker, pushbutton or key mechanism) is held in the ON position, after which it returns automatically to the OFF position. This is a "Normally Open" switch. A "Normally Closed" switch will break circuit contact as long as it is held in the OFF position, and then automatically return to the ON position. Available in "Center OFF" versions with both Momentary ON and Momentary OFF positions.

Pendant

A type of switch designed for installation at the end of a length of portable cord or cable.

Pilot Light

A switch with an integral lamp in its actuator (toggle, rocker or pushbutton) that illuminates when the switch is connected to an energized circuit and the actuator is in the ON position.

Pull

A switch where the making or breaking of contacts is controlled by pulling downward or outward on the actuator mechanism.

Push Button

A switch with an actuator mechanism that is operated by depressing a button.

Rotary

A switch where rotating the actuator in a clockwise direction makes the circuit connection, and then rotating the actuator in either the same or opposite direction breaks the connection.

Single-Pole, Double-Throw (SPDT)

A switch that makes or breaks the connection of a single conductor with either of two other single conductors. This switch has 3 terminal screws, and is commonly used in pairs and called a "Three-Way" switch.

Single-Pole, Single-Throw (SPST)

A switch that makes or breaks the connection of a single conductor in a single branch circuit. This switch has two screw terminals and ON/OFF designations. It is commonly referred to as a "Single-Pole" Switch.

Slide

A switch with a slide-action actuator for making or breaking circuit contact. Dimmer switches and fan speed controls are also available with slide-action mechanisms for lighting and fan speed control

Surface-Mounted

Any switch that mounts on a flat or plane surface.

Three-Position, Center OFF

A two circuit switch, either maintained or momentary contact, where the OFF position is designated as the center position of the actuator.

Three-Way

A switch, always used in pairs, that controls a single load such as a light fixture from two locations. This switch has three terminal screws and has no ON/OFF marking.

Time Delay

A switch with an integral mechanism or electronic circuit that will automatically switch a load OFF at a predetermined time interval.

Timer

A switch with an integral mechanism or electronic circuit that can be set to switch an electrical load ON at a predetermined time.

Toggle

A switch with a lever-type actuator that makes or breaks switch contact as its position is changed.

T-Rated

A switch specially designated with the letter "T" in its rating that is rated for controlling tungsten filament lamps on direct current (DC) or alternating current (AC) circuits.


Wall plates

Combination

A multiple- gang wall plate with openings in each gang to accommodate different devices.

Decora®

Wall plates with Decora-size openings for compatibility with Leviton’s entire line of Decora devices. Available in a variety of multiple-gang configurations. Screw less-design snap-on versions also available.

Flush

A wall plate designed for flush-mounting with wall surfaces or the plane surfaces of electrical equipment.

Gang

A term that describes the number of devices a wall plate is sized to fit (i.e. "2- gang" designates two devices).

Midway

Wall plates that are approximately 3/8" higher and wider than the standard size that can be mounted onto larger volume outlet boxes and/or used to hide wall surface irregularities. These wall plates are approximately 1/4" deep to ensure a proper fit when used with protruding devices.

Oversized

Wall plates that are approximately 3/4" higher and wider than the standard size and are used to conceal greater wall irregularities than those hidden by Midway wall plates These wall plates are approximately 1/4" deep to ensure a proper fit when used with protruding devices.

Modular

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

Multi-Gang

A wall plate that has two or more gangs.

Tandem

A wall plate with individual gangs arranged vertically one above the other.

Weatherproof (with Cover Closed)

A UL Listed cover that meets specific test standards for use in wet and damp locations with the cover closed.

Weatherproof (with Cover Open)

A UL Listed cover that meets specific test standards for use in wet and damp locations with the cover open or closed.


Surge Suppression

Clamping Voltage

The peak voltage that can be measured after a Surge Protective Device has limited or "clamped" a transient voltage surge.  Clamping voltage must be determined by using IEEE Standard C62 testing and evaluated by UL Standard 1449.

Joule Rating

The measurement of a Surge Protective Device’s ability to absorb heat energy created by transient surges. Note that the Joule rating is not a part of IEEE or UL Standards. It is not as significant a specification as Clamping Voltage, Maximum Surge Current and other parameters recognized by these agencies.

Transient Voltage Surges

High-speed, high-energy electrical disturbances present on AC power lines and data and communication lines, generated by utility switching, motor-load switching and lightning strikes.

Response Time

The interval of time it takes for a surge protective device to react to a transient voltage surge. Note that this parameter is not a part of IEEE or UL Standards and is only based on estimations made by manufacturers.

Surge Protective Device

See "Transient Voltage Surge Suppressor (TVSS)" definition.

Transient Voltage Surge Suppressor (TVSS)

A device designed to protect sensitive electronic equipment such as computers and computer peripherals, logic controls, audio/video equipment and a wide range of microprocessor-based (computer chip) equipment from the harmful effects of transient voltage surges. Also referred to as a Surge Protective Device (SPD).

Maximum (Peak) Surge Current

The peak surge current a Surge Protective Device can withstand, based on IEEE Standard C62.45 test waveforms.

MOV (Metal Oxide Varistor)

The primary component used in most Surge Protective Devices to clamp down transient voltages.

UL 1449 Listing

The industry standard for Surge Protective Devices. A Surge Protective Device must have a UL 1449 Surge Suppression rating on its label in order to verify that the device has been tested with IEEE standardized waveforms. Devices without this identification should not be considered reliable surge protective devices.


See Also:

Electrical Terms


Home Lighting Glossary

Home Safety when Traveling or on Vacation

World Electrical Systems

Frequencies All Around Us

Glossary of Terms Related to Frequencies




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