Electrical branch wiring provides power for every room in your house. Typical branch wiring is made up of three different wires: live positive wire, neutral or negative wire and a ground. These three wires provide the electricity and a protection system at every outlet and switch. The wires are colour-coded to simplify the wiring process, and understanding what each colour means is a small step to understanding residential electrical wiring.
Black hot wire
The electrical supply begins by delivering electricity to lights and outlets through a hot wire. The electrical supply wire is referred to as the source side and is typically black in colour. In North America, the black wire carries 120 Volts of alternating current.
White neutral wire
The white neutral wire is the electricity's return wire from the device it powers to the electrical source. It is required in all circuits to complete the cycle back to the distribution panel. The white neutral wire must be of equal size to the hot wire for a safely designed circuit.
Red hot wire
For devices that require 240 volts of alternating current to operate, the red hot wire provides the second 120 volt source wire. The red wire is commonly used in combination with another black hot wire carrying 120 volts to make the 240 volt load. The red and black wire need to draw their electricity from separate bus bars in the distribution panel to power a 240 volt device.
Green or bare ground wire
The green or bare wire is the safety system for the electricity in your home. This grounding system protects people from electrical shock. The ground wire also allows fuses to blow and breakers to trip. Think of the ground wire as the emergency path for electricity.