How an Electrical Outlet Works
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Electrical Outlet Wiring
A standard duplex outlet has two receptacles. They can be wired independently or as one. A small metal tab between the terminal screws can be removed on both sides to split the two receptacles for independent wiring.
An outlet will ordinarily have either two or four wires connected to it plus the ground wire. When two wires are connected, it indicates that the outlet is probably the end of a branch circuit. If four wires are connected, one or more outlets are likely downstream on the circuit from this outlet.
In most cases a black wire will be connected to the brass screws, which coincide with the smaller, "hot" slot in the receptacle. Occasionally a white wire wrapped with black tape indicates that it is a "hot" wire. Plain white wires connect to the silver terminal screws, which coincide with the larger, common slot.
We recommend that wires be connected to the terminal screws for the most secure connection. Never double up wires to a terminal, use one wire to one terminal screw. Strip about 3/4" of wire bare, bend it to a "U" and hook it under the terminal screw. Stranded wire should be twisted together first. The wire should be placed so that the tightening of the screw has the affect of pulling the wire under the screw rather than pushing it out. In other words, loop it clockwise under the screw so that as you tighten the screw clockwise, the wire is pulled tight under the screw.
Some outlets have holes on the back for ease of wiring. Many professionals do not recommend their use because the wires have a greater likelihood of coming loose. However, to use this connection method, use the gauge on the back of the outlet to determine how much wire to strip from the end of each wire. Then insert the straight wire into the hole all the way to the insulation. Tug to make sure the wires are secure.
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