Transformer bonding secondary neutral and ground 1

[LWFB]

I had one of our installers call with the following question.
Application, The seconday of a power transformer (45kVa 3 ph) the neutral needs to be connected to ground. In this facility the ground wire is commonly bonded to the building steel structure.

Is this common practice or shouldn't the ground be connected at the service point where the power to the primary is derived?

Your thoughts.
Thanks

S Whaley

 

[davidbeach]

Where are you; this is an international forum and the rules differ from place to place. If the NEC is your governing code, the separately derived system is to be bonded to local building steel.

 

[LWFB]

Application is in the US

The Frame ground on the transformer is bonded only to the building steel the neutral conductor is bonded to the ground
there is no grounding conductor bonded directly to the service entrance. Is this a common installation?

Thanks again

S Whaley

 

[rbulsara]

Review NEC Article 250. It is very clear in there.

 

[stevenal]

http://nfpa-acs-01.gvpi.net:8080/rrserver/browser?title=/NFPASTD/7005SB