Page 1 of 7 123 ... LastLast
Results 1 to 10 of 67

Thread: doubling neutral wires in ground bar in panel

  1. #1
    Join Date
    Oct 2014
    Location
    United States, Indiana
    Posts
    365

    doubling neutral wires in ground bar in panel

    A home inspector says having two #12 neutral wires under one screw on the grounding bar in the panel is not allowed. Is he right? Thanks.

  2. #2
    Join Date
    May 2005
    Location
    Richmond, Virginia
    Posts
    23,703
    First of all, if there are separate grounding and neutral buses, you're using the wrong bus.

    Otherwise, unless allowed by the panel maker, he is correct.
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

  3. #3
    Join Date
    Oct 2014
    Location
    United States, Indiana
    Posts
    365
    Quote Originally Posted by LarryFine View Post
    First of all, if there are separate grounding and neutral buses, you're using the wrong bus.

    Otherwise, unless allowed by the panel maker, he is correct.
    Ground bar and Neutral bar are joined from the inspector's photo. My instructor told us years ago that as long as the two wires are the same size, it is allowed. But I don't recall an NEC reference. I will check the panel brand when I look at the house today. Thank you.

  4. #4
    Join Date
    Jun 2004
    Location
    Cherry Valley NY, Seattle, WA
    Posts
    4,814
    Quote Originally Posted by LarryFine View Post
    First of all, if there are separate grounding and neutral buses, you're using the wrong bus.

    Otherwise, unless allowed by the panel maker, he is correct.
    Grounded conductors must be under their own screw. Egc's can be doubled if the terminals are listed for it.
    Ethan Brush - East West Electric. NY, WA. MA

    "You can't generalize"

  5. #5
    Join Date
    Oct 2014
    Location
    United States, Indiana
    Posts
    365
    My continuing Ed instructor years ago told us it is allowed only if the two wires are the same gauge. I don't think he referenced the NEC. Most of the older homes all have this, but what puzzles me is that no other home inspector I've been asked to follow has ever said this is a code violation. And I have been asked to address many home inspections. It's a first for me to see this tagged. I guess I could add an extra ground bar but I'd like to know if he is right.

  6. #6
    Join Date
    Jan 2011
    Location
    United States
    Posts
    8,105
    I think the bigger issue here is neutral current on a ground bar. I've seen cases in person and on the internet where someone will do a panel change, land the neutrals from stoves and dryers on the ground bar only to have the ground bar eventually spark or over heat where its screwed down. I view it like an undersized EGC- its sized to carry brief fault current, not continuous current.
    I'm in over my head...

  7. #7
    Join Date
    Mar 2003
    Location
    Vermont
    Posts
    1,784
    It's a fairly recent change iirc only a few cycles ago>>>>


    408.41 Grounded Conductor Terminations. Each grounded
    conductor shall terminate within the panelboard in an individ
    ual terminal that is not also used for another conductor.
    improbable in older panels .....

    ~RJ~

  8. #8
    Join Date
    Jul 2003
    Location
    New Jersey
    Posts
    26,150
    Quote Originally Posted by Stevenfyeager View Post
    My continuing Ed instructor years ago told us it is allowed only if the two wires are the same gauge. I don't think he referenced the NEC. Most of the older homes all have this, but what puzzles me is that no other home inspector I've been asked to follow has ever said this is a code violation. And I have been asked to address many home inspections. It's a first for me to see this tagged. I guess I could add an extra ground bar but I'd like to know if he is right.
    The CE instructor is incorrect. Although the wording has been in the NEC for the last few code cycles it has been part of the listing of the panelboard for many decades.
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

  9. #9
    Join Date
    Feb 2003
    Location
    New Jersey
    Posts
    3,746
    Quote Originally Posted by Stevenfyeager View Post
    A home inspector says having two #12 neutral wires under one screw on the grounding bar in the panel is not allowed. Is he right? Thanks.
    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.

    I’ve seen many older panels where a neutral and it’s associated EGC were landed under the same screw because of limited ground bar space. The correct way that it should have been done would have been to land each neutral on its own screw and group thr EGC’s together on a separate bar or lug.

  10. #10
    Join Date
    May 2018
    Location
    Boyertown, PA, USA
    Posts
    508
    Quote Originally Posted by goldstar View Post
    I’ve seen many older panels where a neutral and it’s associated EGC were landed under the same screw because of limited ground bar space. The correct way that it should have been done would have been to land each neutral on its own screw and group thr EGC’s together on a separate bar or lug.
    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.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •