# Switch Legs



## slick (Aug 17, 2009)

I am working on a high rise apartment building in downtown Dallas. Can you still use the white wire in a 12/2 m/c as your switch leg? I am being told you can't even if you mark it with tap. Is this true?


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## Fibes (Feb 18, 2010)

slick said:


> I am working on a high rise apartment building in downtown Dallas. Can you still use the white wire in a 12/2 m/c as your switch leg? I am being told you can't even if you mark it with tap. Is this true?


It can not be used as the switch leg but it can be used to feed the switch, refer to 210.7(C)(2) before 2011 or 210.7(C)(1) in the 2011


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## slick (Aug 17, 2009)

I am looking in the 2008 210.7 and there is no (C). Only (A) and (B)


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## Fibes (Feb 18, 2010)

slick said:


> I am looking in the 2008 210.7 and there is no (C). Only (A) and (B)


My mistake, I meant to say *200*.7


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## slick (Aug 17, 2009)

10-4 Thanks for the help


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## Dennis Alwon (May 9, 2009)

Fibes said:


> My mistake, I meant to say *200*.7


 Look specifically at 200.7(C)(2) as stated


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## kbatku (Oct 18, 2011)

I can't remember the code ref now, but as I recall you can't put interruptible power on a white - (foggy old code remembrance).


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## Dennis Alwon (May 9, 2009)

kbatku said:


> I can't remember the code ref now, but as I recall you can't put interruptible power on a white - (foggy old code remembrance).


I think you are talking about switching a neutral... No?


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## OaklandElec (Jan 4, 2011)

kbatku said:


> I can't remember the code ref now, but as I recall you can't put interruptible power on a white - (foggy old code remembrance).


He's talking about back-feeding a switch with mc, not switching a neutral. At least I hope. 

The NEC says reidentify the conductor, but I prefer not to. It makes it easy to know which is line, which is switch leg. Any electrician would know exactly what they are looking at, and anybody who would tie it into a neutral shouldn't be doing electrical work.


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## ralph (Apr 6, 2008)

white as a switch leg, shouldnt be practiced. just bringing power in a swtch loop for something. Course I have to admit, that today I fed and loaded a 4 way, which means i sent power on a white to a 3 way, but I sent the load on the white to the other 3 way. Had to do it.old estate, and zero chance to get any more wires to those boxes


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## kbatku (Oct 18, 2011)

I can't remember where it is, but it's there (or was 20 years ago). "No interruptible power on the white" means when you are dead-ending a three way, the common on the DE is (re-identified) white (constant power). Also single pole 240 v tstats, tie the whites together (re identified) and break the black. 

The rationale being that some idiot testing a wire - no power - thinks it's a neutral. If the white wire is hot when he tests it - obviously a power wire. This was a bigger deal back when re-identifying wires wasn't so common - it was just assumed that a "qualified electrician" would be looking at the makeup & know what was going on.


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## btharmy (Jan 17, 2009)

You are going to have to use 12-3 if you are under the 2011 code to meet the requirement for a neutral in the switch box. So, re identifying the white to feed the switch becomes a non issue anyway. Under 2008 and earlier, feed the switch with the white (re-identified) return on the black was fine, if it was cable. With conduit it is a no-no.


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