My house is completely wired with AC cable. After having some previous questions answered on this forum, I decided to open up the sub-panel in my living room to take a look and noticed that the neutral bar and ground bar are bonded and there are neutral wires going to both bars. Since my house is completely AC cable, I don't have any ground wires from the individual feeds to the individual breakers but there is a ground wire connected to the ground bus bar but I can't locate where it's coming from for the life of me. It doesn't go to my main panel. How completely screwed up is this installation? Is there any reason why the ground and neutral bars would be bonded in a sub-panel in the home? I'm completely terrified it was done incorrectly.
Sub-Panel clarification w/ AC cable
- Thread starter nyc_terp
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hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
Since it’s Type AC, the armor is the equipment ground which in turn is bonded to the panel can, so other than the ground from the panel feeder ( which may also be type AC) you may or may not have grounds going to the ground bar. The neutral and ground bars should be isolated at this point. From what I gather, sounds like someone has brought a grounding electrode to the sub panel if it is ran separate from the panel feeder. It is possible that that panel was originally the service, and was made a sub panel when the service was upgraded. Not enough info to make that determination.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Can you post some photos of the panel?
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
This would depend on the age of the home. The newer ac cable has a metal strip that allows the armor to be used as an equipment grounding conductor however the older ac cable cannot be used as an equipment grounding conductor. In either case the neutrals and grounds should not be bonded together in a sub panel.
Sure thing. I'll post some pics later today.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
It sounds like this sub-panel used to be the main panel, and was not re-wired as a sub-panel when the change happened.
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
Never seen AC cable without the wire or strip, must be really old AC!
See attached image. It was definitely never a main panel because it was added a few years back. Now that I look at it again, I think I may have misspoke earlier. The two bus bars are both neutral bus bars, right? Also, the ground wire at the bottom on the panel was the one I was referring to that I don’t know where the other end terminates. Is this a bad install or no? My friend did it for me and I have no problem going back to him asking to fix it.
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Knuckle Dragger
Master Electrician Electrical Contractor 01752
- Location
- Marlborough, Massachusetts USA
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- Electrical Contractor
I'm not 100 percent sure because of the image doesn't say enough for me. ButIt looks like a typical mlo panel with two factory neutral bars.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
I'm glad that you told us that your friend did this. 
I'm glad that you told us that your friend did this.
Trust me, I was completely disappointed in this too when I opened it up. I’m a contractor and I take pride in my work, my friend clearly does not. May need to re-evaluate my friend. Haha.
Ok, so then It’s not as bad as I thought then?
Any clarification where the ground at the bottom of the panel should land? It’s currently fastened to the neutral bar on the right. Should it be fastened to the panel itself rather than the neutral bar?
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
It not an mlo, and the 100 amp backfeed main has the hold down, all of those bare wires from the AC need to be clipped off, or wrapped around the cable (much easier to just clip them now) It is a pretty ratty looking job! LOL! The green at the bottom probably does go to a grounding electrode somewhere, and since its a sub panel, needs to be moved to the ground bar. Could not tell from the picture if the feeder is also AC. And as Knuckle dragger said, both bars are neutrals, the buss is insulated between them. (The black bar in the back)
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Okay, now we know it's a modern panel. I had gotten the impression that it was as old as BX cable.
Question number one: is the feeder a 3-wire or 4-wire cable?
Question number one: is the feeder a 3-wire or 4-wire cable?
How do I confirm if it’s a MLO panel? I can confirm that the feeder is also ac. To your point about the green needing to be moved to the ground bar, where is it if both of the bars are neutral?
Sorry for my inexperienced questions. I appreciate everyone’s assistance and patience.
it’s 3-wire ac.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
There are no main lugs, so this panel was bought with the plug-on 100a main, making it a M/B panel.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
THERE it is! That's the ground, or EGC bus.
All EGCs, green or bare, should land on that bus, and all neutrals should land on the pair of neutral busses.
The neutral buses should not be connected to the enclosure or the EGC bus, just as with any sub-panel.
The AC cable's housing is being used as the feeder EGC, unless you can figure out where the ground wire you mentioned goes.
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