Neutral Question

tbromsOctober 20, 2011

Would appreciate some insight here. I have power coming in to a light above the mirror in the bathroom and then a switch loop going down to the common side of a 3 rocker switch and then back up from the top rocker. I wanted to use the other 2 rockers to power the light and night light up in the bathroom fan. I ran wires from the 2nd and 3rd rockers up to the respective black wires of the light and night light in the fan. There is a dedicated 20 amp circuit that runs straight to the fan. It powers the fan and also a GFI outlet. I thought I could take the white wires from the light and night light and tie them into the neutral wire for the 20 amp circuit, since it is right there in the fan enclosure. I know sometimes an unbalanced neutral can be an issue, but I thought it might be ok since the only thing on the 20 amp circuit is the fan and GFI. Didn't think a 100 watt bulb and a 7 watt night light bulb would add too much more. But, they don't work at all. The light works above the mirror, but that is it. So it looks like I shouldn't be doing this, but could someone please tell me what's happening here? Thanks!

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are you trying to get power for the lights from the hot wire on the switch loop? thats not ok nor is stealing a random neutral. what you are proposing is about 10 different kinds of wrong. if the fan circuit runs to the fan first, which it sounds like when you say "There is a dedicated 20 amp
circuit that runs straight to the fan.", you can run a 3 wire from the fan to the rocker carry the hot down and 2 switch legs back up, and then it would be OK to use that neutral. I'm assuming of course that your rocker switch is capable of multiple feeds via break off tabs which most are. that could also explain why your current rigging doesn't work.

    Bookmark   October 21, 2011 at 4:13AM
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Right - I'm trying to power the bathroom mirror light, the fan light and the fan night light with a hot wire from the power that comes into the bathroom mirror light box. The 3 rocker switch only has one common on one side, and then 3 separate terminals on the other side. So it cannot take multiple power feeds. If I run a neutral wire from the bathroom mirror over to the fan and hook the neutrals from the fan light and fan night light to this, I think it will work. But I'd like to know why the lights won't even light when they are hooked to the neutral on a different circuit.

    Bookmark   October 21, 2011 at 7:59AM
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"But I'd like to know why the lights won't even light when they are hooked to the neutral on a different circuit."
I will not even try to explain. This is a hazard to anyone working on this system in the future. A code violation. I have been severely shocked a couple of times by such hookups. I will kick the a-double-rear of anyone I catch doing such a foolish and dangerous hookup.

    Bookmark   October 21, 2011 at 9:23AM
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Bus Driver - Ok, I get that it is dangerous and a code violation and I need to run a neutral back to the other circuit. But isn't it still technically a complete circuit and shouldn't the light still light? Could you please explain why the light won't light? I'd really like to understand why.

    Bookmark   October 21, 2011 at 10:38AM
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How did you determine the wire is neutral?

    Bookmark   October 21, 2011 at 4:36PM
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You are talking about the one I first hooked the lights to, the one in the fan housing? I know there is a cable that runs from a 20 amp breaker right to the fan housing. I first hooked the white wire from the fan light and the fan night light to the white wire of that cable, and it didn't work. I've since run a neutral from the fan housing back to the light above the mirror, and I have the fan light and fan night light white wires hooked to it. Everything now works. Why didn't it work the first time?

    Bookmark   October 22, 2011 at 10:47PM
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You can't just "run a neutral" The neutral has to be in the same cable with the hot conductors it corresponds with. You would have to run power to the switch first and then run 14/3 or 12/3 to the fan connecting to the neutral and hots for the nite light and regular light. Since the switch can not be divided, you can not run a separate loop switch to the switch. Why it didn't work with your other botched together scenario, I have no idea. In theory it should still light up, perhaps some other variable was in the mix like an unconnected hot. I hate to think of what the installation looks like with a home run entering the fan, a loop switch for the fan, random hots coming from a stacker switch to the fan, a power out feed to the gfci, and a random neutral coming from the vanity light. Forgot about box fill rules and the code on requiring all conductors to be in the same cable or conduit. Not how things are done, you don't just run single conductors around connecting to things until the lights light up.

    Bookmark   October 23, 2011 at 3:00AM
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Once again, this proves that just because you touch two wires together and the lights come on, does NOT mean it was done right.

    Bookmark   October 23, 2011 at 8:58AM
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