I have a client wiring his own subpanel in the shop I built for him.
Shop is on slab, in which I placed, and passed insp, a rebar ground.
In his initial inspection he had separated ground and neutral bus bars and grounded back to the box and to his rebar ground.
When inspector came, he told him to replace that connection and that the neutral need not be isolated back to the main panel.
We’re both confused.
How should it be configured?
Replies
I don't know all the rules (and some of them changed about 5 years back), but, to be clear, is this a separate building or attached to another structure?
Yes it's a separate building about 20' from the existing house.
Ha ha!
Enjoyed your post.
BUT,
still unclear about the rebar ground.
Do we remove the neutral/bond ground AND ground both back to the box and to the rebar ground in the sub-structure?
Thank you,
Pat
You should have a 4 wire feeder to the garage, the ground and neutral should be separate and the rebar (Ufer) connects to the grounding bus. The neutral bus should not be grounded in the garage., It is only grounded at the service.
I'm in Washington state. I have a subpanel serving my detached (I don't think it matters if attached or detached) shop. The neutral bar is isolated from any ground inside the subpanel. It does connect to the neutral in the main panel via a cable. (Once there, it is connected to the ground cuz its then a main panel.) The subpanel grounding bar is bonded both to the foundation rebar and via a cable to the main panel. This setup has been inspected and approved by the electrical inspector.
Exactly why subpanels are done this way is a mystery to me.
It is done because you do not want neutral current flowing in your grounding conductor.. It will impose that voltage drop on the case of your tools (that actually results in a higher voltage when you are talking about the neutral).