Large transformer bonding, not a service location, fed off of a 480V MCC

[godsquadgeek]

The question arose if a ground rod was required for this installation of a transformer feeding a subpanel for a new line in our factory, I said I didn't think so that I thought the MCC ground was sufficient, but maybe to also ground to the beam. Is this okay and legal? We have some workers here that taught code classes and that were unsure and I was not completely sure either.

 

[infinity]

Take a look at 250.104(D).

 

[don_resqcapt19]

See 250.30. The secondary of the transformer requires a grounding electrode and a grounding electrode conductor.

 

[godsquadgeek]

thank you

 

[petersonra]

thank you

See 250.30. The secondary of the transformer requires a grounding electrode and a grounding electrode conductor.

The grounding electrode may not be a ground rod though. Sometimes you can use the building structural metal to connect to a qualifying grounding electrode.