So here’s a new one!
Inspected a condo today in a multi level building. The distribution panel for the unit was two floors down, in the storage area, not in the unit. (so no immediate access to any type of disconnect) The service disconnect was somewhere else on the property, likely at a central location with all the other unit’s disconnects, so I was unable to inspect that one.
However, this distribution panel had absolutely no Grounded or Grounding conductors for the 120v circuits. Just one circuit that goes out the top for a light, and a couple grounding conductors for 240 circuits that you see at the right…
I have never seen this before, so I assume all of the other conductors travel back to the main service panel?
The service feeders also appear to not include an EGC. There is a larger grounding conductor coming into the panel at the bottom left, but it is entering from a different conduit, not sure where it comes from. It is also not separated at the panel, and connects to the main neutral bus.
So for one, I dont see any way for the breakers to sense a ground fault, and then the obvious (neutrals and grounds go elsewhere). Is this allowed??
Odd.
Are any of those GFCI breakers?
Grounds I see on apartment distribution panels connected behind the panel. But not neutrals.
Can you go back to check other things?
No GFCI breakers.
I probably could go back if needed. I did open a couple receptacles, and they looked normal. (3 wire circuits) And the tester didnt find any open grounds or neutrals
Where does the green/ground wire from the one “normal” looking circuit entering the top/right of the panel terminate? It just seems to get lost behind some other wires heading for nothing that resembles a bus bar. Looks like an odd setup for sure.
I’m guessing 1960s/70s era? Likely metal conduit for ground but sure doesn’t explain the lack of neutral wires.
I’d love to see in some of those raceways to see if there are clipped off neutrals. Is it possible some sparkie 50 years ago misunderstood the system and thought only the metal conduit/raceway was needed? I’m intrigued.
These are tough because on the one hand you want to jump up and down screaming “this is totally F’ed up” but the obvious counterpoint is that it’s been like this for 50+ years and working fine 
Conduit to the boxes or not?
The branch circuits all head out one conduit, so maybe there’s an extra junction box somewhere in the closet or floor that holds all the neutrals? Is that a double tap on the service entrance neutral with a black wire, heading out, that could be your missing return path?
@mfellman is right… the existence argument comes into play here. You can’t yet prove it is broke.
That is just for a ceiling light that was added in the same room. There is one small ground bus that it connects to, along with the grounds for a couple 240 v circuits, that’s it.
The units were built in 1986. I am assuming that all the units are the same way, but who knows?
Did you remove the cover plate on the J-Box to the right of the panel? I’d be curious to see if there are wires coming in from behind through the cinder block from the panel.
Yes, that may be the case. I looked inside a couple receptacles, but like an idiot, didnt take a pic. I was just trying to see if it was a 3 wire or 2 wire. The receptacle had a ground connected to it, but I didnt think to see if that ground also connected to the box, or just continued out.
But that would make the most sense, because the bonding screw had been removed.
The larger black wire at the bottom right would be the only option for the neutral return, if they all tied together in the unit somewhere. But there was no visible junction box anywhere. I looked all over, because I was trying to find the panel.
Which is the other question… Doesnt the panel need to be inside the unit, not two floors down?
No, I didnt, because the conduit didnt connect to the panel at all
Ok, I do apartments of that vintage all the time.
The typical setup is a meter and main shutoff in the parking garage,
then hot/hot/neutral to a subpanel in the unit. Hot and neutral are connected
at the subpanel. Then each device box returns hot, neutral and ground to the panel.
At the panel, the ground may be invisible, tied behind the panel.
240V circuits have hot/hot but not necessarily neutral (the ground is usually conduit)
However, having this subpanel in the basement, outside the unit or even outdoors is pretty common, maybe 10% of the units I inspect. I don’t say anything because chances of it getting changed are zero.
With a wire tracer, you can disconnect the neutral from one outlet, and trace the wire through the wall.
What’s weird about your situation is the other condos are apparently wired completely differently.
I only asked because of Matt Fellman’s question about the single green wire. It disappears and we can’t tell where it goes. We’re all trying to play detective and help you out It seems very unlikely that the green wire is ran through the cinder block behind the panel but I’ve seen many interesting things I never would have thought. I know one ground could be insignificant but neutrals and grounds are often family.
I’m in no position to offer advise on this electrical panel, you just have my curiosity and hope someone on this forum can tell what’s going on here.
The EMT at the bottom left has several 240 volt circuits but no 120 volt circuits. It also has a single large conductor tied to the neutral bus. They must have run that to a junction box with the other 120 volt conductors as a common neutral. The EMT is the EGC.
Yes, That is what I have now concluded as well. So other than the junction box being hidden, and not accessible, I guess there wouldnt be an issue with this setup?
I am wondering how to report this, just to keep my own liability. Didnt know if I need to recommend further evaluation, or just not even mention it.
Electrically it will probably work forever if the common neutral is properly sized however the NEC does not permit it to be installed that way. For one the neutral for the 120 volt branch circuits must be within the same raceway as the ungrounded conductors. Also in this type of installation you cannot use a large common neutral for multiple 120 volt branch circuits.
Thanks Robert! and thanks all!
Given the lack of neutral wires evident, are you sure the panel you’re describing is powering your unit and not the building’s common 240 volt loads? Did the legend or other markings on that panel give any clues (ie: lights /plugs /fridge /dishwasher /etc or Panel A /B /House /Mechanical)… That configuration just looks too strange to be a residential condo
Exactly! But heck of a condo!
Yes, this was the distribution panel for the entire unit.
It is very strange, that’s why I needed to share on here…