Conductor A material, such as copper, that permits the flow of electricity; usually refers to the a wire

Conduit A pipe or tube through which wires and cables are run to protect them from the environment and from accidental damage.

Dimmer switch A switch that allows the amount of light from a light fixture to be adjusted to the desired brightness.

Distribution panel The main distribution box that receives the electricity from the external power line and distributes it to various points in the house through individual circuits.

Fuse A device that has a fusible link that melts when a circuit becomes overloaded, opening the circuit and stopping the flow of electricity.

Ground fault circuit interrupter (GFCI) A safety device that continually monitors the amount of current going to the load and compares it to that coming back. If the amount of current returning to the device is less than that going to the load, the device trips (opens) the circuit to prevent electric shock.

Individual circuit A branch circuit dedicated to a single appliance that requires a large amount of electricity, such as an air conditioner or clothes dryer.

Lighting circuit A branch circuit used for permanently installed lighting fixtures, as well as outlets for lamps, radios, televisions, and similar 120-volt devices.

Receptacle outlet A general-purpose device that allows electricity to be drawn off an electric circuit for various purposes, such as radios, hair dryers, and chargers for cell phones.

Service drop The overhead service conductors between the last utility pole and the first point attachment to a house.

Service entrance the fittings and conductors that bring electricity into a building.

Single pole switch A switch that has only two positions (on and off) and serves to open and close the circuit.