Ground delta corner on step-up transformer?
Ground delta corner on step-up transformer?
(OP)
At the utility service entrance point on a 208/120 system we're backfeeding a 15kva transformer to supply 480V for a submersible well pump 1,000 feet away (because the wire is too small otherwise, too difficult to change it out). Does the NEC require (or forbid) us to ground a corner of the 480V delta side?






RE: Ground delta corner on step-up transformer?
I would be more concerned about the resulting voltage drop on motor starting with a 1000' run, the 480 V Tx impedance and the impedance of the 208/120V system. Be sure to check that. You may have to oversize the transformer and get one with taps to boost the voltage.
RE: Ground delta corner on step-up transformer?