480V to 120V single phase transformer

[hhsting]

Does 480V to 120V, 3kva single phase transformer require system bonding jumper, grounding electrode conductor to ground rods?


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[hhsting]

Does 480V to 120V, 3kva single phase transformer require system bonding jumper, grounding electrode conductor to ground rods?


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Anyone?

 

[don_resqcapt19]

It requires all of that. However the connection is to a grounding electrode and that might not be ground rods

 

[hhsting]

It requires all of that. However the connection is to a grounding electrode and that might not be ground rods

What if its used as control transformer and is inside the switchgear see snapshot?

 

[hbiss]

No.

-Hal

 

[hhsting]

No.

-Hal

I dont see any NEC 2017 exception?

 

[hillbilly1]

Is this a listed assembly? NEC does not apply.

 

[hhsting]

Is this a listed assembly? NEC does not apply.

Yes it is but would not grounding electrode conductor be required to be connected transformer?


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[infinity]

Yes it is but would not grounding electrode conductor be required to be connected transformer?


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Is the transformer inside of a piece of listed equipment?

 

[hhsting]

Is the transformer inside of a piece of listed equipment?

Yes


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[don_resqcapt19]

Yes


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Then the code does not apply...you don't look at anything that is part of listed equipment.

 

[hhsting]

Then the code does not apply...you don't look at anything that is part of listed equipment.

Well it does say all wiring within control campartment provided and installed by manufacturer unless otherwise noted. There is nothing noted in compartment that says otherwise. The switchboard is listed. Therefore one can assume code doesn’t apply? No grounding electrode conductor connection too from the transformer?I dont get it where does it say that

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[hillbilly1]

There is probably a factory installed bond, neutral and ground. Nothing else required since it’s listed. A little over engineered, a 3kva transformer with a 3 amp breaker? Doesn’t say what the primary is fused at, other than being a 15 amp fused disconnect.

 

[infinity]

Well it does say all wiring within control campartment provided and installed by manufacturer unless otherwise noted. There is nothing noted in compartment that says otherwise. The switchboard is listed. Therefore one can assume code doesn’t apply? No grounding electrode conductor connection too from the transformer?I dont get it where does it say that

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Listed equipment does not have to follow normal wiring methods set forth in the NEC so anything installed within that equipment is outside of the scope of the code.

 

[hhsting]

Listed equipment does not have to follow normal wiring methods set forth in the NEC so anything installed within that equipment is outside of the scope of the code.

I was talking about grounding the transformer using external grounding electrode conductor and connect to transformer terminal. That would not be required as well?

 

[augie47]

I guess I look at it differently but there is no way the equipment can supply the GES and it does not meet the exceptions so I would require a connection to a GES.

 

[hillbilly1]

I was talking about grounding the transformer using external grounding electrode conductor and connect to transformer terminal. That would not be required as well?

Unless the factory provided a termination point, it would be a possible violation of its listing by modifying it.

 

[wwhitney]

If this were field assembled, and the switchgear is the service equipment, then there is an exception to the transformer requiring its own GEC: 250.30(A)(5) Exception 2.

No opinion on whether 250.30(A)(5) applies if the transformer is manufacturer installed.

Cheers, Wayne

 

[herding_cats]

Thanks Wayne. Ground the body of the transformer directly. If the secondary is 120, you have a "floating" neutral.

 

[hhsting]

If this were field assembled, and the switchgear is the service equipment, then there is an exception to the transformer requiring its own GEC: 250.30(A)(5) Exception 2.

No opinion on whether 250.30(A)(5) applies if the transformer is manufacturer installed.

Cheers, Wayne

Switchboard is service equipment with main breaker of 2500A. Not sure about field assembled. Would not NEC 2017 Article 250.21(A)(3) apply AC systems 50V to 1000V not required to be grounded?