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Light switch problem peter951

Hi yes I do have a bank with 3 switches two are being used for lights already, how do I make the third one live to take another light

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  • kuwaitim
    kuwaitim May 11, 2010

    There are a few things to consider - please excuse any unnecessary explaination if you already have these issues covered.

    Most residential lighting circuits are fed from a 15A circuit breaker. This means (by the electrical code) you can have 1,440 Watts of lighting on that circuit. The circuit breaker can handle 15A but to help prevent internal wall fires, we don't use the maximum capacity (even though your car can handle 7000 RPMs for a short time doesn't mean you should do it all the time). Some lighting is done with 20A breakers - it depends on how your home was wired.

    So - all of that to go through the following steps.

    1) find out what circuit breaker your switches are on - taking note of other lights or outlets that are on the same circuit. If these lights are also fed from the same circuit that your microwave or plasma screen TV are fed from, you may want to reconsider adding this light. Add up the wattage of the lights and potential wattage of other appliances. If it's a 15A breaker, you should not exceed 1,440 Watts. If it's a 20A breaker, you should stay below 1,920W.

    2) Once this is established, and you know you're "good to go" - locate the "HOT" wire in the box where you want to add the switch. The best way to do this is with a tool that detects voltage. You can usually find one at your local hardware store for a few bucks.

    3) Remove power from the box - that is - switch the circuit breaker off. Take your tester again after power has been removed and ensure that there are no other hot wires in the box (if there are - check your breaker, make sure you've turned the correct one off - if so - call an electrician - you may have a larger issue).

    4) Create a jumper wire from the HOT wire to where your switch will go. You will want to "wire nut" it to the HOT wire and then connect it to the switch. There should be 2 screw terminals on the switch - one goes to the HOT wire, the other to the light fixture. If you have 3 screw terminals, one will not be used.

    5) Restore power to the box and you should be good to go. If not, call an electrician. Do not force the breaker on if it "pops" to the off position. Undo everything and let the professionals help you out.

    Based on the information you gave this should do the trick. Remeber - don't be a hero - turn off power before wiring. It's not worth it.


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What is the 3rd switch is used for ??? blank??
another light to a ceiling or to an outlet???

Posted on Oct 23, 2008

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I think what you are asking about is what electricians refer to as a "three way switch"
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