Sub to sub grounding


Old 06-27-07, 11:33 AM
Thread Starter
Join Date: Apr 2005
Location: Houston, TX
Posts: 74
Sub to sub grounding

Here is the situation:
The Main Disconnect is on an outside wall next to the meter.
Directly behind it on the inside wall is the primary breaker panel. Since this primary panel (I'll call Sub#1) is technically a sub panel, the ground and neutral are isolated.
Sub#1 feeds another sub (Sub#2) through another wall 20 feet away which serves only the kitchen circuits (many) and the garage (few).
For the ground conductor from sub#2, is it preferable (or required) to bypass the ground bus on sub#1 and run it directly to the disconnect? Or should I tie it to the still isolated ground bus on sub#1.
Or does it even matter? This is still in the design stage and I can do either.
Sponsored Links
Old 06-27-07, 11:37 AM
Join Date: Sep 2003
Location: Central New York State
Posts: 13,973
Yes, it matters.

You need a four wire cable from sub 1 to sub 2. The ground from sub 2 must go back to the ground in sub 1.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread
Display Modes