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I am a DIYer and am in the middle of renovating my home. I want to do all of this to code, want to clean the breaker box up while I am in there, and want to try and get the final inspection done next week if possible.

I am at the point where I am connecting new home runs into my main breaker box and need some advice and info from all of you professional Electricians out there please.

I have an EATON Type BR 200 amp main breaker box that has two bus bars running down the inside of the box close to the side of the breaker box. The bus bars are connected together and it is my understanding that this means that I can connect my ground wires and my neutral wires to either of these bus bars (either separately meaning the neutral wires on one of the bars and the grounds on the other side OR a mix of neutral and grounds on both bus bars.)

From the research that I have done online, it sounds like no matter what, you can only connect ONE Neutral Wire under one screw and cannot connect more than one neutral wire under one screw on the bus bar. Is this correct?

So with regards to the ground wires, how many ground wires can I connect under one screw on the bus bar? When I read the information from EATON for the breaker box I have, they say the following:

Neutral and Ground Terminals. The Standard terminals on grounds and neutrals are rated to accept (3) #14-#10 Cu/AI or (1) #14-4, provided the cables terminated are of the same material. For larger cables, add-on neutral lugs may be ordered from the accessories on Page V1-T1-66. Note: NEC allows only one current-carrying conductor per hole on the neutrals unless otherwise noted.

I assume a current-carrying conductor would be the neutral and not the ground?

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  • The consensus here of the experts seems to be that you should not mix the neutrals and the grounds in the main panel even though the two bars are bonded. Use one bar for the neutrals and the other for the grounds. One reason to do this is so that later if one wanted to convert the panel to a subpanel, then all one would have to do is remove the bonding link. I believe that one bar is in fact identified as the the neutral and the other as the ground. The neutral bar will not make electrical contact with the case but in the main panel is "bonded" to the ground by a removable linkage. Nov 8 '18 at 18:43
  • Thank you Jim. I appreciate it. What are your thoughts and what does the code say about twisting multiple (2 or 3) ground wires together and putting them under one screw on the Bus bar? Manufacturer says: Neutral and Ground Terminals. The Standard terminals on grounds and neutrals are rated to accept (3) #14-#10 Cu/AI or (1) #14-4, provided the cables terminated are of the same material. For larger cables, add-on neutral lugs may be ordered from the accessories on Page V1-T1-66. Note: NEC allows only one current-carrying conductor per hole on the neutrals unless otherwise noted.
    – John
    Nov 8 '18 at 19:34
  • Ask one of the experts about whether to twist or not. I would first unsert them parallel and see if the set screw holds. Twisting them expands the cross section and they might not fit. Nov 8 '18 at 21:54
  • I presumed that the "they say" portion is a quote from the docs, so I listed that as a quote (pending edit approval). If that was an incorrect presumption, roll back that edit
    – FreeMan
    Nov 14 '18 at 21:55
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Ground wires are limited to 1 under the screw, unless the lug is rated for 2 it will say if it can be. as far as mixing in the main panel to me it it looks neater to mix them, not running a ground to the other side of the panel for breakers on the neutral side, also not running a neutral to the other side with breakers on the ground side. Some inspectors can get really picky on the neat and workmanship clause, although if a large enough panel is not installed to start with then rewiring would have to be done if the panel became a sub to isolate the neutrals. NEC 250.70 not more than 1, and 110.14.A. Both say they can have more if listed / identified. (BTW there are panels that are listed for 3. Grounds under 1 lug)

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  • Thank you Ed. I appreciate it. So, I don't mean to be redundant, but when I read the info from EATON, to me it says I can have three grounds under one lug. Am I just not understanding what I am reading? "When I read the information from EATON for the breaker box I have, they say the following: Neutral and Ground Terminals. The Standard terminals on grounds and neutrals are rated to accept (3) #14-#10 Cu/AI or (1) #14-4" Thanks again for all of your help! :)
    – John
    Nov 8 '18 at 20:57
  • Not sure why the down vote years later, if those panel is listed up to 3 grounds are ok. Neutrals only 1. In a main panel they can be on either side as both busses are bonded by code.
    – Ed Beal
    Jun 19 at 1:47
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There is no code on using the larger screw if needed, but try to use the small screws for smaller wires and leave large screws for larger wires.

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