I ran into this panel during a recent inspection, but did not expect to find 2 hot conductors, one gray neutral and one bare ground. There was no apparent connection between the neutral and ground. This is not a subpanel, although the main 200A disconnect was outside next to the meter. How common is this arrangement?
If the service disconnect is outside this is a sub panel.
That makes it a “sub” panel. The service disconnect is located in the “service” panel. All other panels require a 4 wire feed, with isolated neutrals and bonded grounds (some exceptions apply).
Well, I suspected that would be the answer, although I don’t always see that arrangement in homes around here. So, here’s another question - as you may be able to see from the picture, there are a LOT of neutrals - so many that each could not possibly be landed on an individual terminal. What would be the proper solution for the installer? I would think that a second terminal strip should have been installed.
If there are more neutrals than neutral lugs I would be looking closer at the number of breakers installed vs what the panel max is.
You can’t mix grounds up with neutrals on the busses in a sub either. There is a ground bus system and a neutral bus system, not connected.
Some panels do have expansion kits for the neutral bus and ground bus expansions are available for virtually any panel.
They would install an accessory neutral bar. It is basically another ground bar with insulated standoffs.
That is essentially what I told the homeowner (who was present for the inspection). However, I found it interesting that the electrician who did the work carefully terminated the neutrals and ground conductors on their correct bus locations, but bunched the neutrals - I assume out of ignorance because there were a few screws left unused. Given that this is a 40 circuit panel with relatively few 2 pole circuits, the need for an auxiliary neutral bus would seem to be quite a frequent occurrence.
Depends on the brand and model of the panel. I can count on one hand the number of times when I’ve had to add an accessory neutral bar to a panel that I’ve added circuits to or installed. I’ve seen a great number of panels, however, that should have had them put in to correct existing nonconformities.