When installing a 75kva dry type transformer,
(480delta-120/208wye) If using a water pipe as a ground electrode, does it need to be supplemented by another electrode? Would an equipment ground installed with the primary circuit feeding the transformer qualify as a supplementary ground electrode? thanks

Hi dom!

450-10>>>250-20(d)>>>250-30(a)(2)

a start..

dom,
If the transformer feeder originates in the building service equipment, you can install the GEC in with the feeder conducotrs. See the exception in 250-30(a)(3).
Don(resqcapt19)

Is there a different requirement for the ground electrode for the main switchgear(250-50) and a ground electrode at a transformer fed from a subpanel in the same system?(250-30(b)(2).- 250-30(a)(3).
thanks