Subpanel Bonding Screw

Dave,
Yes all the NM is stuffed into that one hole, well most of it anyhow. There was another “bundle” in the upper left. As for derating I will let one of our resident electricians answer that. My guess it yes it will derate somewhat but the built in safety factors may make it a wash. Generally, the NM is secured to a scab piece of wood above the panel and from what I have seen around here, there is no conduit other than the threaded piece you see in the picture. This will act as the bushing where the NM passes through the cabinet. Obviously the drywall prohibits any inspection as to how well they are secured. As far as bundling with a piece of wire, tie wrap, etc. that just makes it easier to keep things out of the way while they are wiring up the panel. They should be removed but often aren’t.

The two neutrals are a no-no in general. I will call them out but it is something that happens frequently. Just a sign of laziness on someone’s part, especially when an open lug is just below the doubled up one. Seems it would be harder to fit two wires under one screw than on separate lugs. Generally for 220 circuits the white should be remarked, but it rarely happens. I did check one of my books and my prior statement is almost verbatim what the authors (Doug Hanson, Redwood Carson, and Mike Casey) said in the book. The neutral and ground sharing the screw is a no-no as well. I have seen them on the same bar, but under the same screw is just wrong. Again this is a laziness factor as they could have just run the neutral over to the other side very easily.

I think Joe wanted to see the pictures of the set up for both panels. I probably should have gotten a better picture where the conductors are entering the box. I do that normally but got a little sidetracked when my client asked a few unrelated questions. There were other issues so I put a blanket “have both panels reviewed and corrected as needed” type statement in my report. The bushings and such were part of the problems listed in the report.

Hope that helps and I am sure others will chime in if I missed something.

I am left wondering if the unused bar on the right is intended for the grounding wires and therefore may be connected to the enclosure. In addition to removing the bonding screw, perhaps the bond strap/wire between the bars on either side of the breakers also needs to be removed to isolate the neutrals … :wha?:

Also, notice the lack of a proper connector at the bottom left. :shock:

http://www.nachi.org/forum/attachment.php?attachmentid=1438&d=1140397503

When and where in TX will you be?

Sorry. Just realized this thread was from 06. :roll: