On Sun, 05 Jul 2009 02:58:00 -0400, Spehro Pefhany
wrote:

On Sat, 4 Jul 2009 23:40:18 -0700, the renowned John E.
wrote:

I have been asked to offer an opinion in a sensitive situation.

A machinist moved his shop across town and required some rewiring (3-phase
outlets, conduit, etc.) in order to locate some machines where he wanted
them.

He hires a guy who's not a pro (and later discovers is not insured) but has
done shop wiring before and had a good attitude and track record. The guy
does good work. No complaints about the quality of his work.

Owner throws the switch, all works fine.

The story continues 4 weeks later when the very expensive CNC fries its
controller PCB to the tune of $4000.

Turns out the voltage in the shop was upward of 245 and the taps in the CNC's
power supply were set for 220.

What is the legal and moral responsibility of each party?

What will not be helpful are replies about the character or intelligence of
either of the players or their actions.

Thanks.

IMO, 11% high voltage over nominal should not "fry" the controller
board in the first place.



Yes. The controller was overly fragile, or it may have just had a
random failure unrelated to supply voltage. That happens.

If the owner blames the electrician, don't use him again. Sue the
power company for providing 245.


John