Transformer for a single piece of equipment

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Richterfan

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I have to install a 208v 3 ph 75kva xformer to a 480v 3 ph piece of equipment. Do I need to run a conductor from the xformer to building steel, or since its supplying a single piece of equipment I dont need to go to building steel and can use just bonding bushings?
 
infinity said:
This is a step-up transformer? Will the secondary be operating as ungrounded?
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It doesn't matter. The answer is the same for both grounded and ungrounded systems. A connection to a grounding electrode is required. The only difference is that the grounded system will have a system bonding jumper and the ungrounded one won't.
 
Its a step up, and its straight 208 in and straight 480 out. The conductors feeding the xformer had a ground in it to the disconnect, so if I carry it through I dont need to go to building steel or I do?
 
Richterfan said:
Its a step up, and its straight 208 in and straight 480 out. The conductors feeding the xformer had a ground in it to the disconnect, so if I carry it through I dont need to go to building steel or I do?
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you need to connect to a GE. you also have to bring in the EGC with the feed conductors. They are seperate.

i realize this sounds absurd (and probably actually is absurd) but it is what is required to comply with code.
 
don_resqcapt19 said:
It doesn't matter. The answer is the same for both grounded and ungrounded systems. A connection to a grounding electrode is required. The only difference is that the grounded system will have a system bonding jumper and the ungrounded one won't.
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Got a code reference? And if ungrounded a connection to what?
 
Rob,
250.30. (A) is for grounded system and (B) is for ungrounded systems. The only real difference is that you don't have a system bonding jumper or a grounded conductor with an ungrounded system.
 
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