Electrical Home Wiring Basics

Turn the Power Off

• Remove electrical power to the circuit under work. Turn the breaker off, or remove a fuse to effectively accomplish this.

Connecting Wires

• Electrical wires connect to each other for power to flow through. Use appropriate connectors for the situation to maintain safe electrical installation. Using electrical tape to cover connections violates the National Electric Code.

  The National Electric Code requires the use of wire nuts when making electrical connections. Wire nuts come in different sizes to accommodate different numbers and sizes of wire.

  The largest wire nut is blue and will connect 14-gauge to 6-gauge wire. A proper connection requires a minimum of three 12-gauge.

  Gray wire nuts connect 6-gauge to 18-gauge wire. It can connect two to six 12-gauge wires.

  Homeowners will seldom need a wire nut larger than the red one. It connects 8-gauge to 18-gauge wire. It can connect from two to four 12-gauge wires.

  The smallest wire nut suggested for residential electrical connections is yellow. It connects 18-gauge to 12-gauge wire. It connects two or three 12-gauge wires.

  The smallest wire nut commercially available is orange. It connects 14-gauge to 22-gauge wire. You may find these inside electronic appliances, but they are too small for residential electrical connections.

Making Connections

• When making electrical connections, follow the manufacturers' directions for the wire nuts you will use. Strip the wires to be connected about 1/2 to 3/4 of an inch. Place them side by side, and tightly twist them together clockwise using electrician's pliers. Twist the wire nut onto the wires clockwise until it stops.

  The wire insulation must extend inside the wire nut with no bare wire visible. If you can see bare wire, remove the wire nut, trim the excess length off the end using electrician's pliers and replace the wire nut.

Wire Size

• Most homes use Romex 12-2 with ground. It consists of three 12-gauge copper wires, two of which are insulated. One insulated wire is covered in white insulation and the other in black. An outer insulation binds all three wires together in a cable that protects the interior insulation from damage.

  The black wire connects to the electrical source (hot) wire. The white wire connects to the neutral (return) wire. The third uninsulated wire is the electrical ground. It bonds to the box containing the wire connections and the other ground wires.

  Other wire sizes include 12-3, 10-2, 10-3, and 8-3. Outlets that provide electrical power for large appliances like stoves, air conditioners, and clothes dryers use these larger sizes.