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Ground bars are full? Can I add second ground bar? (picture inside)

4160 Views 12 Replies 7 Participants Last post by  afjes2015
My main service panel is QO30M200 and the ground/neutral bars are filled.

You can see the previous owner/electrician installed two or even three wires under some of the ground bar screws which I'm not sure is allowed.

I'm adding a sub-panel and the neutral lug requires 3 spaces on the ground bar.

Here is the picture:

The right-side of the panel looks to have two ground bars. (one of them is slightly beneath the other)

Can I add a similar second ground bar to the left side? If so, does anybody know what part number I need?

Thanks again so much and I apologize for asking so many questions.
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You can buy a ground bar kit that mounts to the panel case and move the bare grounds to it. You can add one on each side. White wires are supposed to be only one per hole. Bare grounds are permitted more than one per hole.

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You can add an independent grounding bar to the left and below the one you have, now. It doesn't have to be directly under the existing one.
You do not have a ground bar, both of the bars are neutrals. The bar you add can only be used for grounds.

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Thanks! If I add an independent ground do I need to connect it to the neutral bar?

Can I just screw into the metal box (and wood behind it) and that’s it?
Those are JUST neutral bars.

This panel makes use of an exception in Code that says, in *main* panels, the neutral bars may be used for grounds.

You can tell they are neutral bars, because the panel provides facilities to isolate them from the chassis, an essential characteristic of a neutral bar in any but a main panel.

If you want ACTUAL ground bars, they are readily available for sale for most panels in the $6 range, and typically fit near the corners. The panel label will probably recommend particular models of that manufacturer's ground bar, and there are probably holes already drilled and tapped for those. They do not locate where you would think; a ground bar is *supposed* to be in direct metal-metal contact with the metal box chassis, so they just mount directly on it.
You don not have to connect the new ground bar to the neutral bar. That is accomplished by both being connected to the case of the panel. Scrape off the paint where the new bar is connected. Some people like to run a #6 between the neutral and the new bar but it is not a code requirement.
If my panel doesn’t have the homes for a ground bar, what kind of self tapping screws would I need?
If my panel doesn’t have the homes for a ground bar, what kind of self tapping screws would I need?
You can not use self tapping screws. You must drill and tap the hole.
Got it. Thanks again! I looked at the panel again and didn't see any pre-tapped holes for a ground bar.

I picked up a ground bar and 8-32 tapper with machine screws so I think I'm all set.

I'm not sure if the #6 copper ground with fit under the ground bar screws, but if not can I use a neutral lug kit to attach the ground cable as well?
You will see threaded holes in the back of the panel for the grounding bar to be screwed into. You should see a green bonding screw already in the neutral bar which screws into the panel housing which serves as a jumper.
Your ground bar mounting holes are marked by the arrows in the picture I uploaded. There is a set on both sides of the panel.
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Unless someone else can find where, but I don't see where the neutral bar is even bonded to the panel - no strap and I think (where I placed the red circle) should be a bonding screw.

Hard to see in the picture with my old eyes so if someone else can see where this main panel is bonded please let me know.

You need to bond the neutral bar to the panel somehow. Then when you install the additional ground bar it will also be bonded to the panel.

I may not have worded this correctly but I think you guys got my drift here.


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