The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!

Featured:

2017 NEC and Related
2017 NEC
Now Available!

Recent Posts
Safety at heights?
by HotLine1
Yesterday at 08:51 PM
International Wire Colour Codes
by Texas_Ranger
Yesterday at 03:29 PM
Looking for older post
by Texas_Ranger
Yesterday at 03:22 PM
Last time to chat here
by Trumpy
01/20/17 11:41 PM
Unsafe Situations
by Trumpy
01/20/17 09:46 PM
New in the Gallery:
Desk-mounted "power-board"
Shout Box

Top Posters (30 Days)
Admin 35
HotLine1 21
Ruben Rocha 17
gfretwell 16
Trumpy 15
Who's Online
0 registered (), 66 Guests and 10 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#203227 - 09/15/11 09:58 AM 175kw Generator grounding
Micmann Offline
Member

Registered: 04/22/05
Posts: 20
I have a set of drawings from an engineer for a 175kw 120/240 single phase generator. In the drawing he has two ground rods at the generator and bonds the rods and the generator with 4/0 copper. He then shows the 4/0 copper running to the structure and bonding at the structure main/ATS (the main and ATS will be in one unit) with the grounding system. From the breaker in the generator he has two paralleled 1/0 running with the generator feeders as equipment grounds. My question is does the 4/0 from the rods and generator casing need to run to the structure grounding system? Isnít the generator breaker the first disconnecting means and if the neutral and ground are bonded together in the generator doesnít the paralleled 1/0ís satisfy the grounding of the structure not needing the 4/0 to be run all the way to the ATS? Iím not asking to doubt the engineer. Itís mostly for my own knowledge for future installations to make sure Iím not missing something I donít understand.

Thanks
Mic

Top
2017 / 2014 NEC & Related Books and Study Guides
#203231 - 09/15/11 10:56 AM Re: 175kw Generator grounding [Re: Micmann]
gfretwell Offline


Member

Registered: 07/20/04
Posts: 9066
Loc: Estero,Fl,usa
The grounding conductors are all going to be bonded together. The only question is how you deal with the grounded (neutral) conductor. That will depend on whether it is switched in the transfer equipment.
The ultimate goal is that you only have one main bonding jumper in the system in either condition (utility or generator)
_________________________
Greg Fretwell

Top


ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals