[wolfdog]

Not directly related to your question, but National Electric code (2008 250.2(A)(1) requires that if the transformer is supplied (primary side) with more than 150v to ground, then the secondary side must be grounded. Just something to watch for.

Kevin

You might want to double check that.

 

[wolfdog]

You cannot design for the unexpected.
Friday night I was called by a customer because the conduit to the air cooled chiller had blown out. It was run in conduit with a prorly sized ground conductor. I know because I installed it 7 years ago. The cable TV people had grounded their box to the 2" chiller conduit with a clamp...that was not tight. A power company feeder cable went down in the alley and hit the cable feed. The cable feed went hot - don't know what voltage but I suspect 13,000- and went to ground thru the clamp on the chiller. It arced and heated up, melting the insulation of the 1/0 conductors inside. Then the fireball of a phase to phase short blew out a whole in the conduit and in the brick. It took out the feeder fuses to the chiller. I was 1:30 in the AM getting temporary power restored and the chiller back on line. All because of a loose ground clamp.
You cannot design for the unexpected.