Electrical Circuits – How to Check If Properly Grounded

electricalelectrical-panelgrounding-and-bondingwiring

I have a Cutler Hammer CH30e panel. On the right side on the panel there is a neutral bus with the a #6 cu ground and a 1/0 Al THW neutral. The bus is also connected to the panel
enter image description here

enter image description here

What I find very strange is that on the left side of the panel where I'd expect to find a ground bus, there are two lugs with all the grounds from the panel connected to them and screwed into the panel.

Is this proper? I have never seen this done before. Should the grounds have been connected to the empty slots on the neutral bus?

enter image description here

Here are the labels from inside the panel. It appears I can use a CH9G ground bar but I don't know how I'll get it in there as the 2-2/0 AL go right up that left side

enter image description here

enter image description here

Best Answer

No, that's not right. -- Unless UL says it is (i.e. if they approved the labeling and instructions for the lug to say that you can do that). But I really doubt that.

Retrofit a ground bar. They are readily available in the $7 range. Your panel probably has holes pre-drilled and pre-tapped for an accessory ground bar; add a photo of your panel's labeling and someone (ThreePhaseEel :) might even be able to identify the particular Eaton part number that will fit right up.

Then attach the wires 1 per hole, or whatever the ground bar's labeling/instructions tell you to do.

About separate bars

In a perfect installation, this N-G bond is a heavy wire (or several, redundancy allowed) that, ahem, you can put a clamp meter around.

In a best-practice installation, they may skip that, but still put neutrals and grounds on separate bars -- not least, this makes it easy to convert a main to a subpanel.

Worst-practice (but still legal) is to simply declare all bars neutral+ground bars, and simply land all neutrals+grounds onto the nearest convenient bar. Obviously, that makes it a lot harder to put a clamp meter around the neutral-ground equipotential bond, or convert to a subpanel.

So it looks like somebody started out doing the "best practice" version of this, with neutral on one bar and grounds on the other.... and somebody else came along and added a circuit with the latter doctrine.

Since fully separated N-G has its usefulness, and it's 95% done already, I would maintain that in this panel.

Those MWBCs

One other thing. Judging by the red+black wires, it looks like you have some multi-wire branch circuits. From the numbered stickers being out of sequence, it also looks like breakers have been moved around. This combination is a recipe for disaster. To fix it, follow each red wire back to its origin cable, identify the red+black pair from that cable, then follow them back to their respective breakers. Make sure the breakers are adjacent (240V between them) then add a handle-tie ($3) or replace both breakers with a 2-pole ($9).