Hi,
I have a question and I was hoping I can get an educated opinion. I was inspecting a condo built 1993. In the electrical subpanel, there are no grounding wires for the individual circuits. There are 3-slot outlets that test properly, with no open ground. Does this mean they are using the conduit as ground? Is that considered “OK” to do? I removed the cover plate and did see a green wire connected to the ground lug on the outlet, but I did not see what it was connected to at the other end. Also, isn’t it possible to do a false ground and connect a jumper from the ground lug to the neutral lug on the outlet? How should I note this in my home inspection report? Is it OK to use the conduit as a grounding for a modern electrical system? Isn’t that just bonding, when the circuit does not have its own dedicated ground wire? I appreciate any thoughts.
Thank you, Justin
We need pictures to be of more help. It’s legit to run the ground separately, it (was) legit to use the conduit body, and various other methods were used.
From a code perspective, it’s what was permitted at the time of construction.
From a safety perspective it gets more complicated.
Probably…
Yes…
Yes, did you see that?
Bonding.
What you are not seeing is called a limitation. You can not see lighting circuit grounds terminating on the terminal bar or where the terminations are located.
What you observed was the outlet gang box grounding/bonding as they should be.
Using the armored cable, or conduit, is acceptable for grounding. One way you can determine this, is to unscrew the receptacle from the box, and then test again. You will likely have an open ground when testing it outside the box. Was it a metal box? There are 3 different ways basically that you could have a grounded receptacle.
- With a standard, grounding conductor as part of the NM cable,
- Through a grounding wire that connects to the receptacle, and then to the metal box
- With a self grounding receptacle, that is grounded only when it is connected to the metal box.
(Both 2 and 3 will require a metal box, and a metal conduit traveling back and bonding with the electrical panel)
Could be code compliant as installed. A few photos would help. What is the wiring method AC cable?
That’s “armored cable” not “alternating current” cable. Although strictly speaking you could say it was AC AC cable. Acronyms, don’t you love 'em! 
That’s correct, type AC cable (armored cable) straight from the NEC.
320.1 Scope. This article covers the use, installation, and construction specifications for armored cable, Type AC.
320.2 Definition. Armored Cable, Type AC. A fabricated assembly of insulated conductors in a flexible interlocked metallic armor.
The grounding conductors could be tied together at a location outside the panel box.
That would be unusual for the time period it was built.