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The photo below shows the upper end of my main panel which is a 200A ITE EQ Load Center. I have a bunch of questions about grounding and neutrals here but I'll start with one on the design:

At the points marked "B" in the photo there's a black wire -- looks like about #8 or maybe #10. It runs from the neutral / ground bus bar on the right, behind the main breaker, and up to the top where it connects to the incoming service neutral. It appears to be the only connection between the bus bar and the service feed. There's a similar wire on the left. How is this wire sufficient to handle the possible load on the neutral bus in a 200A panel? Does the design work simply because the wire is so short (probably 6 - 8" or so) so there will be very little voltage drop and hence little heating even if the loads in the panel are highly unbalanced? Or is there something else going on that I'm missing?

Thanks!

(Per request, photos of UL label on door and ITE label inside panel have been added)

main panel breaker and neutral / ground bars

UL door label

ITE label inside panel

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  • I think it is a listed/tested distance inside of the panel/device. I have a large motor(5HP), it has a connection box at the motor that uses maybe 18gauge wires to the inside of the motor. I need at least 6 gauge from house to motor. From the looks of that picture guess the next question is about A, the picture does make it look bad.
    – crip659
    Sep 4, 2022 at 13:31
  • There is normally a (non-visible, as it's behind everything) direct heavy gauge metal bracket connection from the incoming neutral (in the center) to the neutral bus bars on each side. Not sure on this particular panel, specifically.
    – Ecnerwal
    Sep 4, 2022 at 13:49
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    Why is there a bare ground passing in front of the two hot lugs? That looks like an arc-flash waiting to happen... Sep 4, 2022 at 13:57
  • The distance is what I thought too. But I also imagined that it might be a heavy metal bracket, just can't see. I guess I will have to turn off and remove the main breaker to be certain -- or at least remove enough neutrals to see exactly how the neutral bar is constructed.
    – trawson
    Sep 4, 2022 at 14:13
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    That is not the panel labeling we are after. That is just the model number of the cover. We're looking for a sticker with much more detail. It may not be on the door, it may be in the gutter or sides of the panel. Sep 4, 2022 at 19:19

1 Answer 1

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It appears to be the only connection between the bus bar and the service feed.

There's the trouble.

Right by your mark "C", there's a screw, and an obvious horizontal bar about 1" (25.4mm) wide. You can see it on the left side, also. That bar actually goes all the way across, and forms an inverted "T" with another bar coming down from the neutral lug at "B".

The small screw at "B" is not a terminal intended to mount wires. It appears to be fastening the neutral lug to the neutral bar, the "T".

Disclaimers.

If for some bizarre reason the netural bars as provisioned could not provide the needed service, and someone needed to add another wire to the neutral lug, then they need to use a different lug which is listed for the purpose. Double-tapping a lug is a code violation unless the instructions say you should do that, and you conform with the metal type and size restrictions in those instructions. UL approves instructions when they approve equipment. Assume the factory neutral lug was approved for one (1) wire.

NEC requires 1 neutral wire per screw on the neutral bar. Grounds can be combined 2-3 if the labeling says so, and you can always add accessory ground bars that attach to the enclosure steel. There are no accessory neutral bars. You have enough neutral spaces, so says UL.

No screw should be messed with without the use of a torque screwdriver to set torques to proper spec. This is true of every screw in this enclosure, except the screws which mount the bus assembly to the outer box.

However, the half-wits who put these weird straps in there were obviously having some sort of a problem. No idea what the problem was. But don't be surprised if removing them re-introduces a problem they fixed unsafely. I hope you will chase that problem, then, and arrive at a proper and Code legal solution.

If you reach a point of despair with the panel and must go to a new panel or simply want more breaker spaces, take careful note of the make of all costly (AFCI or GFCI) breakers and get the panel make approved for the greatest number of them. E.G. The correct breakers for an ITE panel are Siemens, and assuming most breakers in it are ITE/Murray/Siemens, get a Siemens panel.

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  • I thought that horizontal bar went all the way across too, but I just looked very carefully and it does not. It only runs between the upper and lower bars. The black wire is in a regular screw on the neutral bar, at the letter “B” at the lower right in the photo. At the letter “B” in the top center it's under a clamp that is part of the panel, not added. There's a symmetrical wire on the other side. This image which is from an unrelated online source shows the same wires and the same little clamp and screw where the service neutral comes in: i.stack.imgur.com/pCOLc.jpg
    – trawson
    Sep 4, 2022 at 22:06
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    @trawson it has to connect. It might be concealed by that contact shield, since they are trying to keep it away from the hot terminals. Sep 5, 2022 at 21:35
  • I agree, certainly it has to be connected somehow. When I get a chance I will turn off the main and the solar, remove all the neutrals from one side, and see if I can see what's going on. If it's connected via a horizontal bar, which makes sense design-wise, then I can't figure what the black wires are for.
    – trawson
    Sep 6, 2022 at 0:49
  • Since the wire is not close to the lugs I suppose you could put a clamp ammeter on it, but if it's handling any current at all I would be alarmed. That shouldn't be. Sep 6, 2022 at 0:53
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    @trawson when commenting on a question or answer, the creator always gets notified, so the \@creator is redundant and the system deletes it. However it works in other contexts. Sep 6, 2022 at 22:53

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