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Home > Switches & Outlets > 4-Way Switch Wiring Options > Identifying the Correct Screw on 4-Way and 3-Way Switches

# 4-Way Switch Wiring - Identifying the Correct Screw on 4-Way and 3-Way Switches

By Donald Kerr

## Toolbox

With any 4 way switch circuit, a 3 way switch must start and end it, you may have as many 4 way switches between 3 way switch (1st) and 3 way switch (last).

One 3 way switch MUST have the circuit power supply ungrounded conductor (aka hot) attached to its common screw, and the at the other end of the switch circuit another 3 way switch must have the switched fixture feed (ungrounded conductor {aka hot}) attached to its common screw.

## The Common Screw of a 3-Way Switch is the Odd Color Screw.

If you look at each of the main connection screws on a 3 way switch you should have no problem in determining that one of the screws is distinctly different in color or one screw is darker than the others. That one screw that stands out from the other 2 is the common screw connection. It is very important that the correct wire is connected to the common screw of the 3 way switch, or the switch circuit will not operate properly. Of the remaining 2 wires that connect to a 3 way switch , it doesn't matter which of the remaining 2 wires connect to which of the remaining2 screws, as long as one goes on each of the remaining screws.

## 4-Way Switches

On 4 way switches there is no common screw as such, but there are matching pairs. you will find that of the4 main connection screws on a 4 way switch, 2 screws will match, and there will be another 2 screws that match, one set will be distinctly different in color or darkness than the other pair. Now the matching pair could be on one side of the switch and the other pair could be on the other side of the switch, OR it could be that the matching pair be on the top left and right and the other matching pair could be on the bottom left and right.

Now when wiring the traveler wires between switches, make certain that when connecting to the 4 wayswitch that the 2 wires coming from the previous switch connect to a matching pair of screws on the 4 way switch, and the other matching pair of screws on the4 way switch connect to the 2 wires leading to the next switch, otherwise the switch circuit will not operate properly.

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