Grounding SDS Generator at Concrete Pad

[faresos]

Hello Everyone:

The customer planning on using a generator (800KW) to back up the entire facility via ATS-4 Poles. The generator is about 400ft from the building its serving and a concrete pad will be provided. Would providing a ground ring buried 24" around the pad with ground rods at each corner of the pad will be adequate to meet the NEC intent for grounding electrode?

The customer is planning on renting a portable generator (before buying the permanent Gen set), are the portable generator (800KW) normally are separately derive system (SPD)?

Thanks,

 

[faresos]

Hello Everyone:

The customer planning on using a generator (800KW) to back up the entire facility via ATS-4 Poles. The generator is about 400ft from the building its serving and a concrete pad will be provided. Would providing a ground ring buried 24" around the pad with ground rods at each corner of the pad will be adequate to meet the NEC intent for grounding electrode?

The customer is planning on renting a portable generator (before buying the permanent Gen set), are the portable generator (800KW) normally are separately derive system (SPD)?

Thanks,

Sorry I just noticed I used the wrong acronym for separately derive system, it should be SDS in lieu of SPD.

 

[iwire]

All the NEC would require is one or two grounding rods

 

[dkidd]

Provide a concrete encased electrode (UFER).

 

[iwire]

Provide a concrete encased electrode (UFER).

Unless that pad has a footing under it I would stick with the rods or ring to be NEC compliant

 

[faresos]

Thanks you all for your replies!

 

[Fishn sparky]

Due to the fact that the ATS' are 4 pole (switching the neutral), the generator is now considered a separately derived system and must be grounded per 250.30.

Similar to a transformer, the system bonding jumper connects to the generator neutral bar as well as a GEC that ties to the building grounding electrode system.

 

[faresos]

Due to the fact that the ATS' are 4 pole (switching the neutral), the generator is now considered a separately derived system and must be grounded per 250.30.

Similar to a transformer, the system bonding jumper connects to the generator neutral bar as well as a GEC that ties to the building grounding electrode system.

I'm a little confuse here, are you saying the generator (SDS) grounding electrode conductor must be connected to the building grounding electrode system but not the generator grounding electrode system (ground ring and rods) at the generator pad?

 

[ActionDave]

I'm a little confuse here, are you saying the generator (SDS) grounding electrode conductor must be connected to the building grounding electrode system but not the generator grounding electrode system (ground ring and rods) at the generator pad?

No. Your generator is a remote structure and will have its own grounding e!ectrode system.

 

[Smart $]

No. Your generator is a remote structure and will have its own grounding e!ectrode system.

+1

The building GES will be connected through the EGC run with the generator-to-building feeder.

 

[don_resqcapt19]

Hello Everyone:

The customer planning on using a generator (800KW) to back up the entire facility via ATS-4 Poles. The generator is about 400ft from the building its serving and a concrete pad will be provided. Would providing a ground ring buried 24" around the pad with ground rods at each corner of the pad will be adequate to meet the NEC intent for grounding electrode?

The customer is planning on renting a portable generator (before buying the permanent Gen set), are the portable generator (800KW) normally are separately derive system (SPD)?

Thanks,

If you are using a ground ring as a grounding electrode, then 250.53(F) requires it to be buried at least 30".