grounding a transformer

[tim89s]

I am installing a 125 amp 480 volt main lug panel. This panel would be fed from the main
service. Out of that panel I want to set a 15kva 480v pri 120/208v sec transformer. There is no
grounding electrode remotely close. I came across code section 250.30a5 exception2. Can I use this exception if I change the main lug panel to a main breaker panel suitable as service
equipment?

 

[petersonra]

might be less costly to just drill the concrete and install a couple of ground rods.

I have never understood why it is necessary to put a GEC on a smallish xfmr like this when there is an EGC that could serve the same purpose already there.

 

[augie47]

IMO. No.
Note the wording of the exception specifies the SDS originates IN listed equipment,
Mt thought is that this applies to equipment which has the transformer as an integral part such as SquareD modular panelboard systems.

 

[david]

might be less costly to just drill the concrete and install a couple of ground rods.

you could do that but you still have to bond to the closes grounding electrode that is part of the buildings grounding electrode system

 

[petersonra]

you could do that but you still have to bond to the closes grounding electrode that is part of the buildings grounding electrode system

Yep. was not thinking. my brain is engaged in trying to clean up what ought to be a simple problem but has turned into a mess.