Breaker Box Wiring

[thiggy]

I understand that it is acceptable to place two circuits on one breaker (assuming the load is within limits) by pig-tailing as opposed to placing two cables under the breaker terminal. However, can the same thing (pig-tailing) be done with the neutrals or grounds, when the buss bar is full and a new circuit is being added?

[gjat]

I understand that it is acceptable to place two circuits on one breaker (assuming the load is within limits) by pig-tailing as opposed to placing two cables under the breaker terminal. However, can the same thing (pig-tailing) be done with the neutrals or grounds, when the buss bar is full and a new circuit is being added?

In one sense, you're basically using the panel enclosure as a junction box, it's not really 2 circuits. Typically when that is done, you want to have the least amount of connections as possbile. I'd put both hot ends in the breaker, and you should be able to get both nuetral ends in the same terminal in the neutral bar. 'Pigtailing' in the panel enclosure is messy, can obstruct other wires, and runs the risk of coming apart or shorting other circuits. I've never seen that done and I definitely would NOT have pig tailed connections in the panel.

[crokett]

I've seen pigtailing done in panels. My transfer switch is wired that way. It has to be. As long as it doesn't violate fill requirements it is ok but t can be messy. That said, if you can I would not put 2 wires under one breaker, I would put a junction box outside the sub panel and only have one wire running into the panel. Then there is only one wire connected to the breaker and you don't need to worry about filling up the neutral/ground busses.

edited to add... any splices I do unless they are temporary (not more than a week) are done with crimps rather than wire nuts. Much more secure and take up less room in the box.

[tfischer]

Some breakers are designed to accept 2 wires, some are not. If there are two notches under the screw, you can put two wires there. If it's simply a screw terminal, you should not.

-Tim

[Black wallnut]

If you have 1" wide breakers now you may be able to buy a double breaker to actually have two circuits per 1" breaker spot. To avoid pigtailing you could add an additional buss bar for yout nuetral/ ground which if this is your main panel should be bonded to the box. If it is a sub panel you will need seperate nuetral and ground with the nuetral not bonded but isolated to the box. HTH

This actually might be a good question to ask either your local inspector or a licensed electrician.

[thiggy]

Thanks for all your comments. My main question is not about the breaker (I have room for addl breakers), but about the buss bar, which is full. If I do pig-tail to attach to the buss bar, would I have to step up to a larger gauge for the pig-tail?

[LCHIEN]

technically i can't think of a reason you would (need to up the gauge), the amperage is the same as going through the one breaker if you are bringing the two circuits attached to the breaker back in to the neutral buss.

[thiggy]

Lchien, I am talking about bringing the neutrals from two different breakers together at the buss bar. I do not have two leads on any of my breakers, as I have enough room for the number of breakers needed. I just mentioned pig-tailing the breakers as an illustration of an allowed similar practice. My concern is that since this represents tieing together two different circuits, am I not increasing the possible current flow at the point where I connect the neutrals?

[jziegler]

They sell additional bus bars that can be used for the grounds, at least for some brands of panels. I would look into that first. I also read somewhere (code experts could fill in the detials) that it is OK to put two grounds under a screw in a bus bar, but neutrals all need their own screw. But look for the ground bars first. They don't cost that much, and would probably be the best way to do it. I think that you just screw them to the panel, and that carries the ground.

Jim

[LarryG]

I also read somewhere (code experts could fill in the detials) that it is OK to put two grounds under a screw in a bus bar, but neutrals all need their own screw.

Jim's reply made me second-guess what I'd been thinking, so I ran the question by our electrical consulting engineer (what I should have done at the outset). He replied that the number of wires per screw depends on the rating of the lug. He guesses that the neutral buss will allow only one wire per screw, but says to check the literature that came with the panel. I take his wording to mean that if such literature is not available, as in the case of an existing panel, the safe approach is to connect only one wire per screw.

In other words, the answer appears to be, "It depends."