Check out some similar questions!

donf · May 13, 2010, 03:27 PM

Where in the NEC 2008 are the instructions for the proper grounding of a sub panel within the same residential building?

tkrussell · May 14, 2010, 02:45 AM

First off, the NEC is not an instruction book, and is not to be used as one. I know you know this Don, but for the sake of other readers.

Article 250, however you will not find specifically "grounding for subpanels", the issue is how to ground any equipment on the load side of the Main Service Disconnecting Means, see Section 250.24(A)(5) that states this.

From that point on, the neutral shall be insulated and isolated from any equipment grounding.

I wonder why you ask, there must be hundreds of threads where this topic has been beaten to death.

donf · May 14, 2010, 09:32 AM

TK,

I'm working on a design to place a sub panel at the bedroom side of our home and I wanted to make sure I correctly grounded the panel.

I am a very long way from having the plan formalized.

The reason I could not find the info I needed was because I was in the wrong section. I was looking in the "panelboards" and then "Grounding and Bonding".

tkrussell · May 14, 2010, 11:52 AM

OK.

Best advice I can give is to read the code in the order it is written, and apply any section ahead of any others first.

A "subpanel" in a home that contains the Main needs a four wire feeder, the neutral insulated, and the equipment ground bare or insulated.

At the sub, the neutral bar does not get bonded to the metal box of the panel with the green screw or jumper, no bare or green equipment grounds are allowed to connect to the neutral bar. Grounds will connect to a separate equipment ground bar that connects to the metal box of the panel with machine screws.