Installing an Electrical Outlet


The following instructions illustrate the general wiring procedure for 120 volt outlets in the United States. Before using these instructions, specific state electrical codes should be checked for specific requirements.

WARNING: 120 volt household electrical systems are dangerous and improper procedures can result in serious injury  or death. Only individuals familiar with electrical wiring and safety practices should install electrical outlets.

Special terms used in these instructions:

Tag out  - Placing a label on the electrical service circuit breaker indicating that the circuit has been opened for maintenance and that it should only be closed by the person working on the circuit. In some situations tagging out requires that a lock be placed on the circuit so that it can not be turned on by unauthorized individuals.

Wire nut - Plastic insulating connector used to connect electrical wires.

Wire stripper - Tool specifically designed to strip the insulation off electrical wire.

Circuit tester - An inexpensive tool used to test electrical circuits to see if they are live. Circuit testers can be purchased at most hardware or building supply stores.

Ground - The part of the circuit that goes to the ground buss in the circuit box. In these instructions the bare copper wire is the ground wire. The green screw on the outlet is the ground screw.

Neutral - The part of the circuit that goes to the neutral buss in the circuit box. In these instructions the white wires and silver screws on the outlet are neutral. WARNING: in improperly wired systems or some specialized applications the white wire and silver screws may not be neutral, and could be dangerous.

Hot - The part of the circuit that is connected to the electrically charged buss in the circuit box. This is the dangerous part of the circuit! In these instructions the black wires and gold screws on the outlet are hot.


Starting point:

These instructions assume that the electrical wiring and outlet box have previously been installed and at least six inches of wire is available in the box. It also assumes that there are only two sets of wires in the box. In some circuit configurations there may be more than two sets of wires. These instructions do not cover those cases.

WARNING: Be sure to turn off and tag out the electrical circuit to the box before starting this procedure.

Required tools and supplies:

The circuit at the outlet:

The diagram below illustrates the wiring circuit of a typical outlet. 


Wiring diagram of outlet The gold line represents the ground wire in the circuit which is the uninsulated copper wire in the box. It is important and normally required that the ground wire is continuous and is wired in a way so that it remains unbroken if the outlet is removed or damaged. Notice that in the diagram it is shown as continuous with a connecting wire going to the outlet. The ground wire is conected to the green wire on the outlet.

The gray line represents the neutral wire in the circuit which is normally the white wires in the box. The white wires are connected to the silver screws on the outlet.

The black line represents the hot wire in the circuit which is normally the black wires in the box. The black wires are connected to the gold screws on the outlet.



Procedure:

Follow the steps listed below to install an electrical outlet:

1. TURN OFF AND TAG OUT THE POWER TO THE OUTLET BOX.

2.  Test  to be sure that the power if off to the box with the circuit tester. Test both wires coming into the box. Do not hold or contact the copper of the wires when testing.

Photo of outlet wiring 3. Pull the wires out of the box as far as possible. They should extend approximately six inches.

4. Strip approximately 3/4 inches of the insulation from the ends of the white and black wires using a wire stripper or by scoring the insulation around the wire with a knife and pulling off the insulation. If using a knife, do not score the copper wire.

5. Connect the ends of the uninsulated ground wires plus the four inch connector wire using a wire nut to produce the continuous ground and connector wire.

6. Bend the ends of the wires to go around the screws on the outlet using needle nose pliers. Bend the wires so that the bend will go in the direction of the tightening screws on the outlet.

7. Attach the ground (bare) wire to the green screw on the outlet using the connector wire. Be sure the bend at the end of the wire goes the direction of the tightening screw.

8. Attach the white neutral wires to the two silver screws on the side of the outlet.

Note, most outlets also have holes into which the wires can be inserted to connect them, but using the screws is more secure and allows easier removal.

9. Attach the two black wires to the two gold screws on the other side of the outlet.

10. At this point some people wrap electrical tape around the sides of the outlet (top to bottom) to cover the exposed screw connections. It is not required for the outlet to function, but reduces the chances of touching hot connections or shorted wires.

11. Stuff the wires into the box by bending them in a vertical "S" curve and pushing them back into the box until the outlet is flush with the box opening.

12. Secure the outlet in the box using the screws supplied for that purpose.

13. Attach the outlet cover plate using the screw provided.

14. Turn on the circuit to the outlet and remove the tag out tag.

15. Test the outlet using the circuit tester.