Still stuck on Separately Derived Systems.

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The Iceman

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Please help.:confused: I have a transformer 480V to 120/208V over 1KVA, feeding two panels all next to each other in the middle of a warehouse. The Structural Metal grounding conductor has been cut. I know this needs to be repaired 250.104 (D)(2). Do I need to bond to the nearest available metal water piping system 250.104(D)(1)? I get confused on the exceptions. Is their any other grounding requirements for this situation? I checked out all the other transformers in the building and the only grounding on any of them is the structural steel. Reading 250.30 (A)(3) also makes me think I need to bond the grounding electrode conductor to the metal water piping system.
 
The Iceman said:
Do I need to bond to the nearest available metal water piping system 250.104(D)(1)?
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250.104(D)Exception No. 2: A separate water piping bonding jumper shall not be required where the metal frame of a building or structure is used as the grounding electrode for a separately derived system and is bonded to the metal water piping in the area served by the separately derived system.
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Sounds like you can't varify this therefore I would bond it. Is it close and inexpensive to do?

Or is this one of your practice questions Ice?:smile:
 
The Iceman said:
It might be. If it is, does it matter where in the building its bonded?[/quote

Take look at the exception that Chris posted. You may not require an additional bonding jumper.
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chris kennedy said:
Sounds like you can't varify this therefore I would bond it. Is it close and inexpensive to do?

Or is this one of your practice questions Ice?:smile:
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No sir. This is a real life situation. So if the metal water pipe is grounded anywhere in the building, then I don't need to bond the separetely derived system to it? What I'm getting at is the water pipe, if already gounded, doesn't need to be bonded again at the separetely derived system?
 
The Iceman said:
No sir. This is a real life situation. So if the metal water pipe is grounded anywhere in the building, then I don't need to bond the separetely derived system to it? What I'm getting at is the water pipe, if already gounded, doesn't need to be bonded again at the separetely derived system?
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As I read it once is enough. And don't call me sir.:wink:
 
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