DIY Electrical Tools and Materials Glossary
This page offers a glossary of electrical terms, tools and materials used in residential electrical systems.
Amp: Short for ampere, a unit of measure for current. The amp rating for a device or cable determines the amount of current it can safely handle. Household circuits begin at 15 amps and go up to about 50 or 60 amps.
Armored Cable: Electric cable with spiral metal sheathing. Early armored cable, BX cable, carried two electric wires with no ground. The metal sheath served as the ground. Later versions carried an aluminum ground wire wound in the spiral. Newer armored cable includes an insulated ground wire.
Bus Bar: A long copper bar inside a service panel or breaker box. All neutral and ground wires are attached to a ground bus bar to complete the electrical path. In some cases a service panel will have a separate neutral and ground bus bar.
BX Cable: See Armored Cable.
Cable: Two or more wires housed in a sheath. Romex, NM and BX are all names for household electrical cable. The gauge of the wire inside the cable will vary. Standard household electrical cable in the U.S. ranges from 14 awg (american wire gauge) to 6 awg, with 14 having the smallest copper conductor and 6 the largest. 14 gauge wire is used for 15 amp circuits, 12 gauge for 20 amp circuits, 10 awg for 30 amps, 8 awg for 40amps and 6 awg for 50 and 60 amp circuits. All cable from 10 gauge down to 6 gauge, have 4 conductors; 3 for carrying electricity and 1 for ground. The smaller 14 and 12 gauge cables may have 3 or 4 conductors. The three conductor cables are referred to as 14/2 and 12/2. This means there are two wires that carry electricity and one ground. 14/3 and 12/3 cable, used for wiring 3-way and 4-way light switches, has three conductors and one ground. 12/3 cable may also be used for 240 volt 20amp circuits such as those used for heavy duty air conditioners.
Circuit Breaker: A heavy duty circuit switch located in the service panel designed to instantly shut off electricity if an overload or short occurs. Circuit breakers are rated for the amount of current they can carry. 15 amp circuit breakers are used with 14 gauge cable for general purpose lighting and receptacle circuits. 20 amp breakers are used with 12 gauge cable for heavier loads such as refrigerators and dishwashers. 30 amp breakers are used with 10 gauge wire for electric driers and kitchen ranges.
Conduit: A channel through which an electrical cable is run to protect or conceal it. Conduits come in metal which is attached to walls and ceiling with screws and brackets. Or plastic conduit is available for easier installation with two-sided tape to stick it to walls and ceilings.
Continuity: The uninterrupted path of electricity. A wire from one end to another has continuity install a switch between the two end and turn it off to break the path and interrupt the continuity.
Double Gang Outlet Box: A wall outlet box that houses two fixtures side by side as with two wall switches at a door.
Duplex Receptacle: A wall outlet with two receptacles.
Fish Tape: A rigid, flat metal tape used to run electrical cable thru an existing wall or ceiling. The rigid nature of the tape makes it possible to push it past most obstructions in the wall cavity by turning the reel to either side. See Run New Wiring for more about fishing cable
Fuse: A copper device designed to separate and stop the flow of electricity if a preset current rate is exceeded.
Greenfield: Flexible metal conduit for running new electric wiring. Resembles armored cable listed above.
Ground Fault Circuit Interrupter (GFCI): A wall receptacle with a built–in circuit breaker used in bathrooms, kitchens and other wet spots to instantly disconnect the circuit in case of a short. Special GFCI circuit breakers are also available for extra safety when installing hot tubs and other circuits used in damp or wet locations.
Junction Box: An electical outlet box containing a cable splice and covered to protect the connection.
Lineman's Pliers: Essential for cutting thick cables. Also use these pliers to twist wires together for splicing.
Multi-Meter: Test for continuity, voltage, current and resistance. Both analog and digital meters are available. A digital meter is simple to use, easy to read and inexpensive. Analog meters are not as easy use or read and are becoming obsolete.
Needle-nose Pliers: Handy for tight spaces. Bend wires into a hook when connecting them to outlets, fixtures and switches.
NM Cable: (Non–metallic cable) Household electric cable with a plastic sheath.
Old Work Outlet Box: An outlet box with built–in clamps to fasten it to drywall or plaster. All that is needed to install this box is to cut a hole in the hollow part of a wall. These can be used in drywall, plaster or paneling. Best suited for wall outlets. Because they don't offer much support old work boxes are not a good choice for installing a new ceiling fixture.
Outlet Box: Any of a number of sized and shaped boxes used to house electrical fixtures like switches, receptacles and light fixtures. They are normally installed by nailing to studs and joists and are available in metal and plastic.
Receptacle Analyzer: A plug-in device that will detect the wiring configuration of an electrical outlet. Thru a system of lights this tester will confirm a receptacle is properly wired as well as indicate a problem with the wiring and what the problem is. This is important for polarized, grounded receptacles that can be improperly wired and still power a lamp or other simple test device.
Romex Cable: A brand name for NM cable.
Service Panel: A breaker or fuse box. Electricity enters the household circuitry thru the service panel and is distributed from there thru circuit breakers or fuses.
Switch Loop: A two wire cable run from a light fixture to a switch on a wall. Its only function is to control the on and off state of the fixture.
Wire Cutters: Use these to cut cable and wire. Use lineman pliers to cut NM and other thick cables.
Wire Strippers: Remove insulation from wire without damaging the copper conductor. Most strippers have a cutting notch for wire gauges from #10 to #18. Most wire strippers will also have a cutting edge for quick cuts of individual wires. Use lineman pliers to cut NM and other thick cables.
