Additional Bus Bar for Grounding - In Main Panel

Hello all,
So, I don’t know that it’s incorrect, but curious as to why the set-up is like this. Main service panel is Square D, service cables come up into the bottom of the panel and the main ground wire goes to the main grounding bus bars that are connected, all looks good. However, there is a separate bus bar to the left side of the panel that also has a main service ground to it and has all the ground wired attached to it. Is anyone familiar with this set-up?

That is wired as a sub panel, was there a disconnect outside or somewhere else?


Interesting. Yes, there was a separate disconnect that was added next to the meter.

I have seen that setup before. Kevin has it.

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That would then make this a sub-panel, and in that case the ground bus is isolated from the neutral bus and bonded to the panel. So it all looks good from here. :+1:


If it’s indeed a sub-panel, that does not sound right. The neutral bar should not have an EGC/GEC connected to it. The two bus bars are neutral bars, and the separate bar on the left is a ground bus bar. I cannot see exactly what you are referring to in the pics. Do you have a better picture of this “main ground wire” going to “main grounding bus bar”?

What is the age of the home/panel?
From your description of the (two) disconnects, the exterior disconnect is likely an “Emergency” Disconnect set-up.

It’s a recent remodel, all the electrical was swapped out from old fuse boxes… Even found some old Knob & Tube wiring up in the attic

The cropped photo is what I have. the 2 red arrows in the picture are going to the two ground wires coming out of the service cable. The yellow arrows are the two connected bus bars and the green arrow is to the grounding bar off to the left

Okay, so that is a little different :slight_smile: The red arrow on the right is a neutral (grounded), that is not a ground. The one on the left (red arrow) is a multi-strand AL uninsulated EGC/ground from the disconnect outside. Those are not main ground conductors. At first I thought you were referring to GECs.

Also, if the panel outside is the main, then the cable that feeds the sub-panel inside is a “feeder” not a service [entrance] cable.

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In my area, that would require the Service be upgraded to current requirements by the AHJ.


If the disconnect outside is an emergency disconnect, would you still consider the inside a sub-panel?

You tell us. Is this the main panel? Since, I do not use the 2020 NEC, I wonder how service disconnect and main panel identifications is handled?

My gut says no but again, I’m using the 2017 NEC.

No. But that is 2020 NEC (230.85) and must be labeled as an emergency disconnect. Square D QO and Homeline panels only have “neutral” bus bars. Where a separate ground bus is needed (as your panel) it is added as a stand alone bus bar just as yours is.


As Robert K. noted, the fact they added a busbar for the grounds when there are plenty of open spots on the neutral buses indicates that this is likely set up as a sub-panel. Something to check would be verifying that the panel bond screw is not installed for the neutral buses.


It is fed by a 4 wire.

Two ground wires would not be coming out of the service cable.

An auxiliary ground bar does not necessarily mean that this is a remote panel. They can be installed in service panels also.

More clarification is needed.


Where are you located, your profile doesn’t say. Check which NEC code you guys have adopted, also check whether or not your locale had amended the emergency disconnect (ED) requirement in any way.

According to NEC 2023, whether the inside panel is a sub-panel or a main panel will depend on how the outside ED is implemented. There are several ways it can be done, and in all cases the ED must be labelled. If labelled “Emergency Disconnect, Service Disconnect”, then the inside panel is going to be a sub-panel. This is exactly how the inside panel was wired before the ED requirement with outside main disconnect. Everything after this main disconnect was a sub-panel. So, today, if you took this main disconnect and relabelled it “Emergency Disconnect, Service Disconnect” you would meet the new ED requirement. Now, the other option for ED, if labelled “Emergency Disconnect, Not Service Equipment”, then the inside is going to be the main panel with service disconnect and wired as such.

The addition of the ED made things only more confusing and complicated :slight_smile:

This thread is a good example of why the correct terminology is important. The terms like grounding electrode conductor (GEC), equipment grounding conductor (EGC) and neutral conductor should be used. This will be helpful if the report is later passed on to an electrician for evaluation or comment.