# Question about 2 3way switches same power source



## AllanJ (Nov 24, 2007)

You got it right.

Note: You will need an at least 22 cubic inch box for the switch shown at top right (much later correction: top left), assuming 14 gauge wiring.


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## Beepster (Oct 19, 2009)

AllanJ said:


> You got it right.
> 
> Note: You will need an at least 22 cubic inch box for the switch shown at top right, assuming 14 gauge wiring.


Right in NH means left everywhere else. :wink: Remind me not to drive in NH.

B


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## tlarose (Jul 31, 2012)

I assume the box with the panel wire coming into it? Thanks for the confirmation guys, cheers.


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## tlarose (Jul 31, 2012)

AllanJ said:


> You got it right.
> 
> Note: You will need an at least 22 cubic inch box for the switch shown at top right, assuming 14 gauge wiring.


Okay so I was at Home Depot and the biggest size they had was an 18.5 cubic inch box. 2-3/4" deep. Will I NEED a 22 inch? The only one i see on google is made by Carlon, and it's plastic and blue:thumbdown:

If you know of one at a Home Hardware or Home Depot that's on their .ca site, that would be awesome, but the biggest I saw there was 18.5 and lots of 12.5


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## jbfan (Jul 1, 2004)

tlarose said:


> Okay so I was at Home Depot and the biggest size they had was an 18.5 cubic inch box. 2-3/4" deep. Will I NEED a 22 inch? The only one i see on google is made by Carlon, and it's plastic and blue:thumbdown:
> 
> If you know of one at a Home Hardware or Home Depot that's on their .ca site, that would be awesome, but the biggest I saw there was 18.5 and lots of 12.5


To comply with current codes about needing a neutral at every switch, modify your diagram to feed the lights from the second switch.
This elimanates a pair of wires at the first switch box, and you can then use the 18 cubic in box.


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## andrew79 (Mar 25, 2010)

Wouldn't a 2 inch deep 4 by 4 box with plaster ring be just fine? I get 32 ci for that and you can get it at any big box out there.


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## tlarose (Jul 31, 2012)

jbfan said:


> To comply with current codes about needing a neutral at every switch, modify your diagram to feed the lights from the second switch.
> This elimanates a pair of wires at the first switch box, and you can then use the 18 cubic in box.


That sounds like a better idea, so I can just use the 18 cubic inch box. But I'm not quite sure how to modify it that way.

Made this, but I don't understand how to connect the top and bottom right side switches, and now my left side switches have an empty screw.


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## jbfan (Jul 1, 2004)

All the white wires connect together.
The incoming hot hits the odd colored screw on the 3 way switch.
At the other switch, all white wires connect together, and the black wire that goes to the light fixture hits the odd colored screw.


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## frenchelectrican (Apr 12, 2006)

This is the photo which I do this very often.









That will work the best due you will meet all the code requirement very easy plus you will have netural at each switch location in case you may have mulit location dimmer or timer due their device some of them will required netural to function properly.

Merci,
Marc


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## tlarose (Jul 31, 2012)

Thanks Marc,

So if I were to add a 2nd set of 3 way switches, I'd bring a new 14-2 into the left box, tie the white to the current other 2, so for the black, do I tie it to the black wire from the panel, and pigtail back to the common screw on the switch?

Thanks


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