Sizing GEC in parallel sets

[Zyb]

I have four sets of copper 250kcmil in two conduits, how do I size the GEC

1. each conduit has equal to 500kcmil so I use 1/0 copper per conduit
or
2. total equivalent conductor size is 1000kcmil (4 sets x 250kcmil) thus use 2/0 per conduit

 

[infinity]

Are you referring to a EGC and not a GEC? Is this a feeder?

 

[Zyb]

Are you referring to a EGC and not a GEC? Is this a feeder?

GEC tap to the line side of a switch gear

 

[infinity]

GEC tap to the line side of a switch gear

So this is a GEC from an electrode?

 

[roger]

The GEC is sized per the combined kcmil of the service entrance conductors and the number of raceways is not a consideration.

 

[infinity]

The GEC is sized per the combined kcmil of all the service entrance conductors and the number of raceways is not a consideration.

I agree. Sounds to me like a SSBJ question not a GEC. Maybe the OP can clarify.

 

[roger]

I should have said "each service entrance leg or phase"

 

[Strathead]

If it is an SSBJ as suggested ( installed in a feeder on the line side of the first means of disconnect, then refer to table 250.102 notes at the bottom. But in a nut shell go t the tables int he back. Find the area of the power conductor size. Multiply by the number or parallel. Then multiply by .125. (12 1/2%) that value is the area of the ground required in each conduit. Look in the able again and find the conductor size.

 

[infinity]

1. each conduit has equal to 500kcmil so I use 1/0 copper per conduit

If this is actually a SSBJ then yes you can use the combined size of the ungrounded conductors in each raceway and T250.102(C)(1).

2. total equivalent conductor size is 1000kcmil (4 sets x 250kcmil) thus use 2/0 per conduit

A GEC would be sized according to the combined size of the ungrounded conductors in both raceways and T250.66.

 

[Zyb]

If it is an SSBJ as suggested ( installed in a feeder on the line side of the first means of disconnect, then refer to table 250.102 notes at the bottom. But in a nut shell go t the tables int he back. Find the area of the power conductor size. Multiply by the number or parallel. Then multiply by .125. (12 1/2%) that value is the area of the ground required in each conduit. Look in the able again and find the conductor size.

thank you