Upsized Equipment Ground

[scotteng]

I have a client that has a tenant lease agreement requesting a #1/0 Cu EGC to be run for their 400A tenant service. Table 250.122 only requires a #3 Cu EGC of course. And we are all familiar with the requirement to upsize the EGC when the phase conductors are upsized for VD. But is there anything specific in the code that prohibits someone from increasing the EGC to any arbitrary size just because they want to? Here they are asking for a #1/0, but could we run a #4/0 CU EGC on a 400A service? Never been asked to upsize the EGC before and cannot find anything that says you can't.

 

[zbang]

Not the greatest authority here, but I can't recall anywhere restricting the use of a larger-than-needed conductor with the exception of at terminations (e.g. the "Suitable for 8-2g Cu" sort of thing).

 

[Barney B]

Not the greatest authority here, but I can't recall anywhere restricting the use of a larger-than-needed conductor with the exception of at terminations (e.g. the "Suitable for 8-2g Cu" sort of thing).

All three of the tables in Article 250 which specify wire sizes (T250.66, T250.102(C)(1), and T250.122) specificly refer to minimum sizes.

 

[infinity]

I have a client that has a tenant lease agreement requesting a #1/0 Cu EGC to be run for their 400A tenant service.

Since there is an EGC I'm assuming that these are feeder conductors and not service conductors?

 

[scotteng]

Since there is an EGC I'm assuming that these are feeder conductors and not service conductors?

Correct. Retail building meter center with a 400A meter/main for this tenant feeder.

 

[infinity]

Correct. Retail building meter center with a 400A meter/main for this tenant feeder.

Thanks for the clarififaction. I only asked because if these were service conductors then there would be no EGC. So then as others have stated T250.122 is for minimum EGC size. That can be exceeded if someone designed it that way. Personally it's a waste of someone's money but that just my opinion.

 

[tom baker]

What is the feeder raceway? The EGC is required to be run in the same raceway.
If your raceway is EMT, GRC, INC, those raceways are a much better, or lower impedance EGC, than a wire type.

 

[Jpflex]

I have a client that has a tenant lease agreement requesting a #1/0 Cu EGC to be run for their 400A tenant service. Table 250.122 only requires a #3 Cu EGC of course. And we are all familiar with the requirement to upsize the EGC when the phase conductors are upsized for VD. But is there anything specific in the code that prohibits someone from increasing the EGC to any arbitrary size just because they want to? Here they are asking for a #1/0, but could we run a #4/0 CU EGC on a 400A service? Never been asked to upsize the EGC before and cannot find anything that says you can't.

I think the code says the ground is typically not required to be larger than the largest ungrounded conductors supplying. But can be equal or greater. The lowest size based on table with criteria mentioned. To the best I know anyway?