>>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.
>
>Hard to make the case after 4 weeks that _anything_ the electrician did had
>anything to do with this. At four seconds, or even four minutes, I'd consider
>it obvious. But four weeks went by, and the owner thinks the electrician
>caused this? No way.
>>
>>Turns out the voltage in the shop was upward of 245 and the taps in the CNC's
>>power supply were set for 220.
>
>So what? Equipment designed for 220V should be able to handle 245V. It's not
>the electrician's responsibility to open the CNC machine to see what it's set
>for.
If it were wired to an outlet, I would agree.
A hard wired machine power run, however, should also include insuring that the machine you are hooking up is at least set properly for the voltage you are going to be bringing live on it. As you will have the panel for it open, you should make yourself aware of any voltage taps, so that you don't hook up say a 5% under voltage tap to a 5% or more overvoltage feed.
Any electrician that is a mere, dumb, brain dead wire terminator should be looking toward an industry where his mistakes have less of a catastrophic downside. If you do not take the time to at least examine what you are hooking up, you have no business in the industry.