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#72994 - 12/14/06 05:39 PM ground size
bdonus Offline
Junior Member

Registered: 10/01/05
Posts: 5
Loc: chicago, il
need to know what size groung conductor to use for the main ground to the water pipe for a 1600 amp service with 4 sets of 600 mcm cables to the utility transformer.

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#72995 - 12/14/06 06:24 PM Re: ground size
Luketrician Offline
Member

Registered: 07/08/06
Posts: 273
Loc: Sale Creek, TN USA
With the information given, table 250.122 shows 4/0 if the egc is copper, or 350 if it's al/cu. 250.122 (F) talks about conductors in parallel also. This should get you started.
_________________________
Luke Clarke
Electrical Planner for TVA.


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#72996 - 12/14/06 07:58 PM Re: ground size
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9045
Loc: Estero,Fl,usa
You use 250.66, not 250.122
I read it as the max required will be 3/0 copper or 250 MCM al.
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Greg Fretwell

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#72997 - 12/14/06 08:23 PM Re: ground size
Luketrician Offline
Member

Registered: 07/08/06
Posts: 273
Loc: Sale Creek, TN USA
Thanks, and apologies for the mix-up, 250.122 is for grounding raceway's and equipment. Seen that first part, where it says minimum size egc, and the rest is history.
_________________________
Luke Clarke
Electrical Planner for TVA.


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#72998 - 12/16/06 06:10 PM Re: ground size
Yoopersup Offline
Member

Registered: 03/04/03
Posts: 826
Loc: Michigan
If under the Chicago code its 18-27-250.66 page 93
copper (300) in a 1 1/4 inch conduit or tubing.

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