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I have power from two different circuits in one box. (#1) I have a line (hot, neutral) from one circuit and (#2) hot only from another circuit (3way). I want to install another switch to control a fan in this box and want to run it off the (#2) circuit. Can I use the neutral from circuit (#1) to accomplish this? Logically, I can't see why not as the neutrals all lead back to the same place.

Thanks,
artis
 

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Are these circuits on same breaker??? If so i think this is a wire sizing issue.If not, probally a code violation to tie together.
 

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DGR,IABD
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It will work, but it will be a big red flag waving, jumping up and down code violation. NEC §300.3(B) states that all conductors of the same circuit must be contained in the same cable or raceway. You can't "steal" a neutral from a convenient place.
 

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artis67 said:
Logically, I can't see why not as the neutrals all lead back to the same place.
Logic has a time and a place, and this it NOT IT!
If we thought this way all the time there would be lots of charred homes and other nasty bits.

This is one great big qualm I have with DIY electrical. The "Well, it works. Must be OK" mentality. This is not the way to go about doing electrical work. It is also why we have a big code book to refrence before doing any work.

Short answer; as Marc said, it may physically work but it is a big violation and a very unsafe installation.
 

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Speedy Petey said:
Logic has a time and a place, and this it NOT IT!
If we thought this way all the time there would be lots of charred homes and other nasty bits.

This is one great big qualm I have with DIY electrical. The "Well, it works. Must be OK" mentality. This is not the way to go about doing electrical work. It is also why we have a big code book to refrence before doing any work.

Short answer; as Marc said, it may physically work but it is a big violation and a very unsafe installation.
speedy pete, Would this be code legal if these wires were run in the same conduit.Also can two curcuits share a neutral provided both are in same conduit.
 

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DGR,IABD
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bergenbldr said:
...can two curcuits share a neutral provided both are in same conduit.
Yes, in a residential single phase panel, two circuits conductors in the same cable or raceway can share a neutral conductor if they originate on breakers of opposite phases (legs). The code does also mandate that these breakers be physically located in the panel one right over the other. In a commercial, three phase panel, three circuit conductors in the same cable or raceway can share a neutral conductor if they originate on breakers on different phases (legs). Here again, the breakers must be physically located in the panel three in a row. The neutral current on different phases "cancels out" on the neutral, which is why different phases can share a neutral. Head hurt yet? ;)
 
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