Latest Discussions : Electrical & Lighting

brian3d

01:17PM | 01/12/05
Member Since: 01/11/05
23 lifetime posts
Hello all, first time poster...

I've been in my house about a year now and just discovered that I have ceiling light which shares a neutral with another circuit - one of those situations where 3 way switches are connected with 2 wire cable, leaving no neutral at the fixture. After some poking around, I found out that this is okay if the two circuits are on different phases. I'd just like some clarification: does this mean that one breaker has to be on the left side of the hot bus, and the other on the right? Both are on the same side right now. I figure this is only adding 1/2 amp to the neutral load of the other circuit (120V w/ 60W bulb) but I plan on correcting it anyway if it's wrong.

Here are a couple more questions if I have to move one of the breakers: first, do the neutral and ground need to be moved in the panel to the other neutral/ground bus? (There is one neutral/ground bus next to each hot bus). It doesn't seem to me like they should have to be but I don't know what common practice is. Second, are splices allowed inside the panel? I may need to do that in order to reach another part of the bus bar.

Thanks!

Brian

bcaputo

01:35PM | 01/12/05
Member Since: 12/16/04
16 lifetime posts
House panels are usually single phase, meaning an A phase and a B phase. Using common neutral for a multi-circuit is acceptable under normal conditions. Your use as discribed will not be an issue. Your panel is most likely a then b then a then b etc etc along one side of the panel. Confirm this by checking the diagram in the panel or viewing how the buss bar is connected to the main wiring. With this configuration the breakers being in order as discribed is acceptable.

If this is a main panel the neutral bar and ground bar are usually the same, meaning you do not have to change the neutral wire, again check if the neutral wire from the main wiring goes to each side.

Splices are not acceptable within a panel by NEC code.

brian3d

07:57AM | 01/13/05
Member Since: 01/11/05
23 lifetime posts
Thanks for the info. Yes, after checking the diagram, it looks like the phase alternates a-b-a-b down each side of the bus. However, the two breakers in question are two spaces away from each other so they are on the same phase. It seems it would be easy to switch one so that they're next to each other, one on top of the other. Does that make sense?

Wireman

04:07PM | 01/17/05
Member Since: 12/19/04
62 lifetime posts
The two breakers sharing the common neutral should be located next to each other so one is on a and the other is on b. If you have a tester you will get 220 volts between both breakers if they are installed correctly and nothing if they are installed wrong.

Prior to around 1980 you could not splice in a service panel but that was changed and you may splice in a panel and still meet code.

Ron


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