How To Wire Three Switches On One Circuit - Electrical - DIY Chatroom Home Improvement Forum

 DIY Chatroom Home Improvement Forum How to wire three switches on one circuit

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03-24-2010, 11:18 AM   #1
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## How to wire three switches on one circuit

I am not sure what the best way to wire my theater room.

I am going to have 6 can lights, rope light, and floor lights all controlled by separate switches and I am not sure how to wire this correctly on one 20 amp circuit. Does anyone have a diagram showing this or could they explain it to me.

Thanks.

03-24-2010, 12:37 PM   #2
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Quote:
 Originally Posted by Abs777 I am not sure what the best way to wire my theater room. I am going to have 6 can lights, rope light, and floor lights all controlled by separate switches and I am not sure how to wire this correctly on one 20 amp circuit. Does anyone have a diagram showing this or could they explain it to me. Thanks.
The most straighforward way electrically is to run the power feed (from the panel) to the switch location, aothough it may not be the shortest in terms of feet of cable. Continue the power feed to the next switch box if more than one.

From each switch, run a cable to the first of that group of lights and continue the cable to daisy chain all the lights in that group.

At a switch box connect together the black wire of the incoming power, the black wire of the continuing power if any (not to light fixtures) and short lengths (say 6") of black wire one for each switch.

The black wire of the cable going to a group of light fixtures is connected to the other terminal of the respective switch.

All of the white wires are connected together.

All of the bare wires are connected together with a wire nut, separate from the white wires. You will need extra short lengths of bare wire so each switch has one attached to its green screw and also the box itself, if metal, has one connected directly to it.

All wires must be 12 gauge or fatter if the circuit is to have a 20 amp. breaker.
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Last edited by AllanJ; 03-24-2010 at 12:45 PM.

 The Following User Says Thank You to AllanJ For This Useful Post: Abs777 (03-24-2010)

 03-24-2010, 12:41 PM #3 UAW SKILLED TRADES     Join Date: Jan 2007 Location: Kansas Posts: 5,341 Rewards Points: 2,652 You have 2400 watts available to you on a 20 amp branch circuit. be sure you stay within those limits with your lighting. Just add all the maximum fixture wattage ratings together. A diagram is difficult with out more detail all the switches in one 3 gang box or are they in different locations. Any 3 way switches? If single pole switches in 3 gang box this would be one way of doing things...these could be dimmers also. Attached Thumbnails   __________________ " One nice thing about the NEC articles ... you have lots of choices" Stubbie
 The Following 2 Users Say Thank You to Stubbie For This Useful Post: Abs777 (03-24-2010), drtbk4ever (03-24-2010)

 03-24-2010, 01:37 PM #4 Member   Join Date: Feb 2010 Location: Kentucky Posts: 174 Rewards Points: 214 Thanks for the info guys and Stubbie, awesome diagram, that is what I was looking for.
03-25-2010, 09:14 AM   #5
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Quote:
 Originally Posted by Stubbie You have 2400 watts available to you on a 20 amp branch circuit. be sure you stay within those limits with your lighting.
Isnt it true that you have to multiply that 2400 by 80% which would then be 1920 watts available?

Please correct me if I am wrong.

 03-25-2010, 09:18 AM #6 Just call me Andrew   Join Date: Mar 2009 Location: Albany, NY Posts: 2,271 Rewards Points: 1,032 If it's simply a lighting circuit (known load) it's ok to come pretty close to the actual wattage limit. If you have outlets on the circuit, different story, because you never know what you will plug in. It might make sense to leave a little headroom, though, because maybe you'll want to add to it someday. __________________ Andrew
03-25-2010, 09:22 AM   #7
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Quote:
 Originally Posted by i conduit Isnt it true that you have to multiply that 2400 by 80% which would then be 1920 watts available? Please correct me if I am wrong.
Yes you are wrong. A 20 amp 120 volt circuit will provide 2400 watts. A continuous load for 3 hrs or more is limited to 1920 watts.

03-25-2010, 09:39 AM   #8

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 Originally Posted by brric Yes you are wrong. A 20 amp 120 volt circuit will provide 2400 watts. A continuous load for 3 hrs or more is limited to 1920 watts.
Thanks Brric for answering that question, it is a very common misconception by a lot of people. We often have to claify when the 80% deration applies to branch circuits as this question keeps popping up.....
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03-25-2010, 09:42 AM   #9
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Quote:
 Originally Posted by Stubbie Thanks Brric for answering that question, it is a very common misconception by a lot of people. We often have to claify when the 80% deration applies to branch circuits as this question keeps popping up.....
YW. It's misunderstood by a lot of people including a lot of experienced electricians.

03-25-2010, 09:48 AM   #10
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Quote:
 Originally Posted by brric A continuous load for 3 hrs or more is limited to 1920 watts.
Thanks for the clarification. But what would be considered to need a continuous load for 3 hours or more?

Only things I can think of 'continuously' would be TVs and computers and maybe electric heating.

 03-25-2010, 10:04 AM #11 Master Electrician   Join Date: Mar 2010 Location: Indiana Posts: 4,412 Rewards Points: 5,080 Any thing that is on for 3 hours or longer at a time. Not really relevant to residential other than perhaps heating. Lighting in a store would be an example of a continuous load.
 03-25-2010, 12:07 PM #12 Member   Join Date: Feb 2010 Location: Kentucky Posts: 174 Rewards Points: 214 I should be safe. My can lights are 75 watt max, my rope light is 3 watts per foot, and my floor lights are 3 watts per light (3). I'll be under 1000 watts. I might add some wall sconces as well. This will be in my home theater room, so the lights won't always be on as well.

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