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Thread: doubling neutral wires in ground bar in panel

  1. #11
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    Quote Originally Posted by Craigv View Post
    When you write "group EGC's together", are you referring to twisting together as many as will fit in a given hole in the busbar? I've encountered plenty of those in old panels, and it's a real treat straightening all that out to replace the panel.
    If there is a “rating” shown on the panel cover as to how many EGC’s can be landed under one screw then that’s what you should go by. If not then “grouping” them together and landing them under a lug is a far better option than doubling them up under one screw.

  2. #12
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    You are permitted to join many EGCs and use a single pigtail, as long as it's as large as the largest joined EGC.
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

  3. #13
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    Quote Originally Posted by LarryFine View Post
    You are permitted to join many EGCs and use a single pigtail, as long as it's as large as the largest joined EGC.
    Could the same can be said for neutrals as well?

  4. #14
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    Quote Originally Posted by goldstar View Post
    Could the same can be said for neutrals as well?
    Not unless they are part of the same circuit or multiwire circuit.

  5. #15
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    Quote Originally Posted by goldstar View Post
    If there is a “rating” shown on the panel cover as to how many EGC’s can be landed under one screw then that’s what you should go by. If not then “grouping” them together and landing them under a lug is a far better option than doubling them up under one screw.
    Agreed. I simply dislike the added and unnecessary complexity caused by twisting egc's together in a panel that could otherwise accommodate individual landing. I've never encountered a full panel that was legally loaded (no removed CTL tabs, etc.) that couldn't accommodate individually landed conductors when the busses are rated for single landing only. I assume it must be a listing requirement or at least good design...

  6. #16
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    Quote Originally Posted by goldstar View Post
    Just to clarify what others have already posted, if the HI cited the problem in a MBP the grounds and neutrals are landed on the same ground/neutral bar. The reason you don’t land 2 neutrals under the same screw is because the likelihood that the screw can loosen from vibration or expansion/contraction over time is greater than you might think. If that happens it will begin to arc and could cause the insulation to melt and the loads (like lighting) to flicker. Having 2 EGC’s under one screw doesn’t present that specific problem (but may present others). If you’re in a MLP the neutrals and EGC’s are landed on a separate bar but again, the neutrals shouldn’t be terminated under the same screw for the reason cited.
    ...
    ...
    The other reason you do not land two neutrals on one screw is that to work on one circuit neutral you would also interrupt (at least temporarily) the neutral of the other circuit. Similar to the problem with the neutral of an MWBC, in that you would have to open both breakers.

    Sent from my XT1585 using Tapatalk

  7. #17
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    Quote Originally Posted by GoldDigger View Post
    The other reason you do not land two neutrals on one screw is that to work on one circuit neutral you would also interrupt (at least temporarily) the neutral of the other circuit. Similar to the problem with the neutral of an MWBC, in that you would have to open both breakers.

    Sent from my XT1585 using Tapatalk
    That’s correct and a good point. Should the neutral on a MWBC that has been doubled up become loose it will cause irreversible problems.

  8. #18
    Join Date
    Dec 2008
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    218
    Our AHJ does not allow twisting ground wires together in a panel, they must each connect to a terminal but can be doubled up if same wire gauge and permitted by panel specs. Individual landing of neutral conductors which i do, is a considered good practice but not enforced...they allow doubling up same as ground wire. I have never seen a panel with enough ground screw terminals, so I routinely add additional ground terminals... I connect the added terminal to existing terminal with a #6 jumper. Of course the danger of sending 240 volts to 120 volt appliances will not exist in future wiring because multi-wire circuits will be prohibited in residential wiring. I consider this good practice and have not shared a residential neutral in 10 years.

  9. #19
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    Quote Originally Posted by mlnk View Post
    Of course the danger of sending 240 volts to 120 volt appliances will not exist in future wiring because multi-wire circuits will be prohibited in residential wiring. I consider this good practice and have not shared a residential neutral in 10 years.
    When is that going to happen? Do you know something I don’t? AFAIK you are required to use a 2-p breaker as it stands right now.

  10. #20
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    Quote Originally Posted by mlnk View Post
    Our AHJ does not allow twisting ground wires together in a panel, they must each connect to a terminal but can be doubled up if same wire gauge and permitted by panel specs. Individual landing of neutral conductors which i do, is a considered good practice but not enforced...they allow doubling up same as ground wire. I have never seen a panel with enough ground screw terminals, so I routinely add additional ground terminals... I connect the added terminal to existing terminal with a #6 jumper. Of course the danger of sending 240 volts to 120 volt appliances will not exist in future wiring because multi-wire circuits will be prohibited in residential wiring. I consider this good practice and have not shared a residential neutral in 10 years.
    Where are you getting this?
    Yeah, its inconvenient to have a 2-P breaker and have to turn off both circuits just to work on one but in residential that's not too bad. It's often a time & material savings and safe if done correctly. I've never heard anywhere that it will be prohibited in the future.
    If you aim at nothing, you will hit it every time!

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