# Properly grounding / bonding a transformer with building steel



## KnipexUser (Mar 23, 2012)

It's been a while and I just want to ground / bond this transformer with building steel, water, etc. I know the neutral and ground should be bonded in the transformer. So then just bond the transformer to building steel before grounding on the secondary side too? (i.e. do you have to hit building steel from the transformer and on the secondary side).

Thanks for any advice or code help


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## HARRY304E (Sep 15, 2010)

KnipexUser said:


> It's been a while and I just want to ground / bond this transformer with building steel, water, etc. I know the neutral and ground should be bonded in the transformer. So then just bond the transformer to building steel before grounding on the secondary side too? (i.e. do you have to hit building steel from the transformer and on the secondary side).
> 
> Thanks for any advice or code help


Welcome to the forum.....:thumbup:


What type of transformer do you have.?


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## frenchelectrican (Mar 15, 2007)

KnipexUser said:


> It's been a while and I just want to ground / bond this transformer with building steel, water, etc. I know the neutral and ground should be bonded in the transformer. So then just bond the transformer to building steel before grounding on the secondary side too? (i.e. do you have to hit building steel from the transformer and on the secondary side).
> 
> Thanks for any advice or code help


The answer will varies a little depending on what conferation the transfomer you are using.

Merci,
Marc


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## KnipexUser (Mar 23, 2012)

It's a 480v to 120v transformer. I think it's a 75kva


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## Pete m. (Nov 19, 2011)

Take a look at 250.30

Pete


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## nitro71 (Sep 17, 2009)

Basicly you're building the GEC system for your SDS. You can bond in the transformer or in the first disconnect. Bonding in the transformer is how you generally see it done. MikeHolt has a picture somewhere on his website I've seen. 

I bring the neutral to a double lug on the XO. From there I bond to the case with a lug that has multiple taps on it. Bring my GEC, EGC's and other bonding to that point. No hard fast rule on exactly where you bond in the transformer.


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