new light switch installation

Old 12-02-02, 02:23 PM
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new light switch installation

I have a question about adding a new light switch, actually a dimmer switch. Currently, I have two normal flip switches in the wall. One is a three way. I want to replace the three way with a three way dimmer switch. I also want to replace the other switch with a standard dimmer switch. My question is about adding a new third dimmer switch. So on the wall there will be three switches instead of two.

Where do I get power from for the new switch? Can I pig tail from the other switches or do I need to run it back to the box? If I can pig tail, what is the limit of pig tails? Let's say I want to add another switch later on for a total of four?

Any help would be appreciated. I really don't want to call in an electrician unless I have too. Thank you.
Old 12-02-02, 02:44 PM
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Location: Calgary Canada
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The answer to your question will depend on what the new switch is to control and what the switches that are there are controlling. You can only have so much of a load on a breaker. So to answer your questions we need to know a few things.

What is the size of the breaker controlling the switches and related outlets?

What is the size of the smallest wire running these devices #12 or #14?

What is on this circuit such as how many lights and what type are already being used on the circuit, any other load TV, microwave, etc?

What and how many is the third switch to control?

Is the box the two switches in large enough to support a third switch? Or even the wires to control another switch ? Need to know the cubic inches of the box usually stamped inside?

Do you have a ground wire present?

If you can get these answers then you can get a much better response.
Old 12-02-02, 03:20 PM
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Breaker is 15a.

#14 same as what is in place throughout
the house currently. Box is already there
and installed when house was built. Room was unfinished.

8 lights total- 4 zones:
4 lights on one switch.
2 on another switch.
One light on one switch.
One light on the last switch (future).

No other load than the lights at this time.

Wall is exposed so I was going to replace
the duplex box with a quad.

Does this help?
Old 12-02-02, 04:31 PM
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Any good book on home wiring will give you a number of options to do this. The best option will depend on many factors.

Also, be sure to do the computation shown in the instructions for the dimmers. Three dimmers in one box will generate quite a bit of heat, and there will be more limitations on controlled wattage than what is printed on the dimmer packaging. This may or may not be feasible.
Old 12-02-02, 05:26 PM
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It appears you can do it but I'd sugjest you heed Johns advice. Get a good book so you have some understanding about the method that might be best for you and check the dimmers labels so you don't put them in a situation of creating too much heat.
Old 12-03-02, 08:03 AM
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Thanks for the advice. I didn't think about the heat with
three dimmers. I may just use two and a standard switch.
I will go get a book today and check it out just to make
sure. Thanks. I will post back and let you know how it
Old 12-03-02, 08:41 AM
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I wouldn't be concerned about heat if you have 4 fixtures connected to 3 dimmers. Compare the wattage of the load to the rating of the dimmer. You may have a 150 watt fixture connected to a dimmer rated at 600 watts. Go to an electrical supply house for the 4-gang box. Ask for a 4-gang "industrial" cover and a box that matches the cover.The size of this box plus the depth of the cover will avoid a box that is cramped with wires and devices.----Good Luck!!

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