Grounding a transformer.

[Danny89]

I have a few transformers at my plant that are grounded to building steel the building steel at some point is grounded to the water pipe feeding our building.

Does this seem to code?

There is no water pipes by the transformer.
I'm guessing this would be ok. As long as at some point the building steel attached to the water pipe at some point...?

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[tom baker]

Your quesiton is too incomplete to answer.
What is the voltage and configuration (480 delta x 120/208 Wye)?
Transformers are required to have a connection from the XO terminal via a grounding electrode conductor to a grounding electrode, which can be building steel.
There is also required to be system bondinng jumper from the XO terminal to the metal case of the transformer.

 

[tom baker]

I'll move this to Grounding and Bonding

 

[infinity]

I have a few transformers at my plant that are grounded to building steel the building steel at some point is grounded to the water pipe feeding our building.

Does this seem to code?

Probably yes, providing there is a system bonding jumper too as Tom mentioned.

 

[david]

I have a few transformers at my plant that are grounded to building steel the building steel at some point is grounded to the water pipe feeding our building.

Does this seem to code?

There is no water pipes by the transformer.
I'm guessing this would be ok. As long as at some point the building steel attached to the water pipe at some point...?

Sent from my Moto Z (2) using Tapatalk

your code reference would be 250.104 (D)

 

[david]

are there metal water pipes in the area served by the secondary derived system

is there a bond between the grounding electrode and the metal water pipe system in the area served by the secondary derived system?

you stated there are no water pipes by the transformer, that is not the same thing as the area served by the transformer secondary

 

[augie47]

your code reference would be 250.104 (D)

I think I would be more likely to be guided by 250.30.
If the installers knew enough to bond to building steel I would say odds are the install is compliant.

 

[david]

I think I would be more likely to be guided by 250.30.
If the installers knew enough to bond to building steel I would say odds are the install is compliant.

250.30 (A) (8) bonding
250.104 (D)

it has bee my experience most installers do not know the metal water system needs to be looked at for bonding

once the grounding electrode conductor is installed to building steel they are done

 

[augie47]

250.30 (A) (8) bonding
250.104 (D)

it has bee my experience most installers do not know the metal water system needs to be looked at for bonding

once the grounding electrode conductor is installed to building steel they are done

My apology, I had misread the OP thinking he was questioning the bonding of the transformer in general.
250.104 and it's exceptions are indeed very relevant.

 

[david]

My apology, I had misread the OP thinking he was questioning the bonding of the transformer in general.
250.104 and it's exceptions are indeed very relevant.

no apology needed i have learned a lot reading your post over many years

hat off to you