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Grounding and Bonding

1444 Views 4 Replies 3 Participants Last post by  Dominick, 
D
So im installing a small single phase !5kva Liebert UPS tomorrow. Im trying to be clear on bonding my raceway which feeds my disconnect. Is a UPS which feeds a !00 amp single phase panel a separately derived system? This UPS does not have a built in transformer. Thanks for any help!
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ablyss
Dominick said:
So im installing a small single phase !5kva Liebert UPS tomorrow. Im trying to be clear on bonding my raceway which feeds my disconnect. Is a UPS which feeds a !00 amp single phase panel a separately derived system? This UPS does not have a built in transformer. Thanks for any help!
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Maybe 250.30(A)(6) Exception No. 2 is what you're looking for:
A grounding electrode conductor shall not be required for a system that supplies Class 1, Class 2, or Class 3 circuit and is derived from a transformer rated not more than 1000 volt-amperes, provided the system grounded conductor is bonded to the transformer frame or enclosure by a jumper sized in accordance with 250.30(A)(1)
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I'm thinking you do need to run a separate grounding electrode as your 5KVA exceeds the 1KVA limit.
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D
I will be running a ground wire to building steel which qualifies as a grounding electrode. My question is since my neutral is not switched do I still need a grounding bushing on my raceway entering my disconnect.
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brian john
Is there in internal bypass with a neutral, if so then it is not a separately derived system.
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D
There is a bypass on the unit, so with that being said it does't need the grounding bushing since its not service equipment or a separately derived system?
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