I inspected a sub panel that had your standard romex coming into the panel. It looked like a rush job and whoever did it couldn’t get to the ground bus. So, they attached the wire to a screw inside the panel. Part of me thinks; “ok, so the screw is attached to the panel just like the ground bus is attached to the panel so it’s conceivable it’s ok.” but the OC part of me says, “no, the wire belongs on the bus like everyone else”. What are your thoughts? Thanks in advance.
I don’t believe that screw is listed and labeled for that purpose…
Dang Larry, you just trumped both sides of my brain and went for the obvious. Thanks for the insight man. I appreciate you!
What Larry said…improper termination.
You do not ground sub/remote panels.
The single neutral terminating on the netral buss should suffice if the system was correctly wired.
A sub/remote panel ground terminal, not a buss, should be bonded to the enclosure.
I have no idea why someone terminated what looks like a ground conductor on the screw for plastic retention channel separating the neutral busses from the metal enclosure.
Subpanels need to be grounded. A single neutral is not enough. If the panel is properly wired post 2008 NEC in a detached structure or anytime in an attached structure it should be feed with a 4 wire feed with a dedicated grounding conductor as well as the neutral. Pre 2008 panels in detached structures were allowed with a 3 wire feed as long as no metallic paths existed between buildings. In those panels the ground was bonded to neutral like a service.
Yes you do.
That is citing code.
As Robert implied a 4 wire system does not make panels down stream safer. If a qualified individual works on the electrical system no problems. We went to a 4-wire system because unqualified individuals were creating paralleled panels and creating hazards.
If you are in a new build and a sub is ran in 3-wire it is a code violation. Not a safety violation.
The OP is safe just not code compliant. That is what makes electrical inspections tricky.
You dare not say that it is safe and you dare not say that it is not code compliant. I like improper termination
The 4 wire feed does make the installation safer as it provides a dedicated ground path without depending on the neutral.
How so? Both methods only have 1 path to ground.
It prevents stray current from the neutral from traveling on all the grounding conductors.
You can’t do that unless you have a dedicated EGC
Arguing with an electrical inspector in a state where home inspector is “not allowed” to remove the cover to an electrical panel. Good luck!
Connections prevent that not the # of conductors. You can safely wire sub panels with 3-wire all day long. They just won’t be code compliant.
Really? Then what is the point of removing the bonding screw at the sub panel?
Wait, I’ll answer for you… it is to prevent current from traveling on the grounding conductors… so how can you do that with 3 wire?
You know, there’s a reason codes change
Yes. And I can teach the code in Ohio. The change was in 2008 NEC. Would you like to learn how?
Yes, since I’ve already asked twice:
Each is HHN / hot hot neutral / no EGC equipment grounding conductor
Apparently we arent talking about the same thing. For the first diagram: Missing bonding at the right sub panel results in 2 things.
1.The enclosure isnt grounded/bonded to the grounding conductors, which can result in the breakers not tripping in the event of ground fault.
2. It also means the grounds and the neutrals are bonded together at the bus bars. Which, like I said, will result in stray neutral current all throughout the home on the grounding conductors.