Connect neutrals together in j-boxes?
Is there anything wrong with connecting the neutrals of multiple circuits together in a junction box downstream of the main panel? In other words, there are 3 hots and three neutrals in EMT from the panel to a j-box the attic. why not connect the neutrals together in the j-box? They’re joined together in the panel, anyway.
Thanks
Bill
Replies
Each circuit should be complete on it's own. It normally won't be a problem, but later put a GFCI or AFCI breaker on one of those circuits and you will be cussed out trying to find those junctions.
No advantage to combining them.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Easy there tiger! You need to know what those circuits are before just tying up all of the neutrals. What if one circuit is 240V, with the neutral really being a hot that wasn't properly labeled? Now, how many grounds (green or bare) wires are in the box? More than likely, you have one incoming hot, and two out-going, all on the same circuit. If that is the case, you can just wire-nut them all together. You need to know where they go first, and just as important, where they are coming from. Trace the wires, on both sides of the box.
Edit: with EMT you don't need a grounding conductor as the metal pipe serves as the ground
Edited 8/11/2008 9:41 pm ET by arcflash
I know what they all are, 3 separate 120V circuits. My only thought was, why not provide a bigger wire when possible? I've seen it done where multiple 120V circuits share a single (larger) neutral- I figured this would be functionally the same.Bill
Hah! I know something about this.
"Is there anything wrong..." Yes there is. What you would be doing is paralleling conductors and you can't do this with wires less than <#1.
You probably have a single phase system since this is a house. That is, id est, two hots or phases, A & B. Since this is in good ole conduit, I don't understand why 3 white wires were pulled in [unless special dedicated, emergency circuits]. Well, you could have all three circuits on the same phase. Then you could also have 2 circuits on one phase and 1 circuit on the other phase. Then one of the circuits of the doubled phase could share the neutral with the single circuit on the other phase. Savings of wire.
Or it is permissable to use a larger neutral wire capable of carrying the total amperage.
I hope this muddies the issue and why you have to go toelectricians school for four years. Like the alliteration?
~Peter
Panel is in one end of the unit. There is 1/2" EMT going to an area above the kitchen. There are three #12 colored wires and three #12 whites in this pipe, which terminates in a 4x4 box. From this box, individual Romex cables go to the Fridge, Microwave, and Dishwasher. Each hot wire goes to it's own 20A breaker in the panel. In the 4x4 box, each hot connects to a black wire in a Romex cable, each white to a white Romex. Since the whites all connect to the neutral bus in the panel, my original question was: "why not connect the neutrals together in the 4x4 box?" I gather from what you said, a single, larger (#8?) neutral could have been pulled down the pipe, but this was not done.A secondary question then arises- if the neutrals are connected, or a larger neutral wire is shared, and the hots are connected to different phases, does this then become a "multi-wire circuit" which would require ganged breakers?Thanks
Edited 8/11/2008 11:38 pm ET by PGproject
The 2008 Code may be different, but my absolutely fabulous understanding is that it would be a multiwire circuit HOWEVER since these wires are not going to a duplex receptacle, it shouldn't be necessary to use a more expensive double pole breaker.
Incidentally, what are the colors of the three hot wires? Since you speak of different colors and "unit", then perhaps this is in an apartment building and that might be three phase in which case only one white, neutral wire would be needed providing that the hot wires were black, red and blue [and if they were installed correctly.
~Peter
It is an apartment, but standard single-phase (2 110V legs 180 degrees apart). The hot wires happen all to be black.