Liability & responsibility of electrician?

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.
Reply to
John E.
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The "electrician" is culpable as it was found that the wiring was to blame. That proof alone means that he would be culpable, regardless of his credentials, or lack thereof.
The owner should bear some blame (as in be lenient in court) for trying to economize costs in the wrong area (he should have paid the licensed and insured electrician).
Also knowing how to hook up systems well, and knowing how to do a proper requirements analysis are two different things and define some of the differences between the grunt pulling the wires and the supervisor laying out the plan and making sure that the machines and their power sources are matched. Since a failure mode did occur, it would be improper not to make a negative statement about the character of the installer.
Also, though it was not a lack of intelligence that compelled the owner to choose the riskier path, it does indicate a lack of wisdom, which I am sure has received a boost due to these events already.
PS Cross-posting is lame.
Reply to
StickThatInYourPipeAndSmokeIt
Probably a good call, since modern switchers, which the DC supplies for these things usually are, can handle up to about 265 volts. Even a bit more, typically.
Reply to
Archimedes' Lever
snip----
Nonsense. The voltage at the panel has nothing to do with the wireman. It's a function of the transformer at the pole. The voltage in my shop, wired with three phase delta, is also upwards of 245 volts.
The only way a wireman could be responsible is if the panel was wired three phase delta, with a high leg, and he had assigned the high leg to one of the 120 volt circuits, yielding 208 or more volts.
The voltage declared indicates that the service is, indeed, delta.
Harold
Reply to
Harold and Susan Vordos
"Archimedes' Lever" "Phil Allison"
** Unlikely it was a SMPS based on the OP's admittedly poor and incomplete info.
Cos SMPS do not have multi-taps for AC input voltage - PLUS if an off-line switcher fails from overvoltage, it just blows the fuse and goes dead.
But losing regulation and over-voltaging the load ( as was alleged by the OP) is another scenario altogether - more often associated with old age or the failure of one of a few critical components in the regulation loop.
..... Phil
Reply to
Phil Allison
Nonsense. If you hire a 'pro' chances are they make even more mistakes. In this case the owner is to blame. He should have hired someone from the company that sells the CNC machines to connect them properly to the mains.
Reply to
Nico Coesel
If a proper electrician does not know how to hook up a machine, he is not a proper electrician.
Pro work is usually insured.
That makes you wrong on both counts.
Reply to
StickThatInYourPipeAndSmokeIt
You're an idiot. If you are wiring POWER runs, you had better know what your loads are, and how they get connected.
Reply to
Archimedes' Lever
A CNC machine is something different than a light bulb. Few electricians know more than how to connect a light bulb and outlets. Besides, the story doesn't tell whether the machine has a permanent mains connection or is connected by a cord.
Reply to
Nico Coesel
Nonsense. 245VAC could *easily* be a [nominal] 240V single-phase service.
Reply to
Doug Miller
Equipment is designed to operate +/- 10% of the nameplate rating. In the case of taps like what happened here, the taps are supposed to be set by the electrician to fall within the 10% range. With the taps set at 220v the CNC machine was good to operate from 218v to 242v. As the power installer, it was the electrician's responsibility to verify the voltage coming into the building and adjust the taps on the machine accordingly. He was paid to correctly hook up power to the machine and failed to do so.
Reply to
Rich.
Perhaps you don't work with many electricians. I work with electricians on a daily basis, and the large majority of them can run the wire to the machine, outlet, light fixture, what ever, but few of them have the ability to make sure it is 100% correct for the equipment powered. I have seen 480 volts wired to 208, and the reverse, single phase wired to 3 phase equipment, wrong rotation, (that had been verified correct by the electrician!), electricians reversing rotation in the equipment so some motors are correct, and some are reversed, you name it! That is where I come in, to double check phasing, verify incoming voltage is correct for the equipment, and to ensure the voltage taps in the equipment is set properly. Unless discussed before hand I would not assume the electrician checked to make sure the equipment was set up for the incoming power. Seems like the owners responsibility to me! Greg
Reply to
Greg O
Maybe, maybe not. My thoughts are the equipment was correctly wired, but not set up properly. Was the electrician paid to do the equipment set up/start up too? If not, it is the owners problem. The electrician could have easily looked at the power ratings tag on the equipment and wired it as such. Any adjustments internal to the machine are the responsibility of the person that did the start up on the equipment, which in this case, my guess, was not done. I have been doing commercial HVAC service for 10 years and have yet to see an electrician verify anything past the equipment ratings tag. Look at the tag, shove the proper wires into the terminal block, and slam the door, we are done, next! We come along afterwards and verify incoming voltage, rotation, and set any voltage taps. Greg
Reply to
Greg O
I know of zero CNC machines that operate from a line cord.
Reply to
StickThatInYourPipeAndSmokeIt
Which makes ALL of them a mere order taker, point to point wireman.
This was not such an installation. If new runs had to be installed, then the installer, if only a mere electrician, is already in over his head if he doesn't know about the equipment to be fed power to.
Reply to
StickThatInYourPipeAndSmokeIt
Yes.
No, or maybe. You're making an assumption unjustified by the facts presented.
As described by the OP, he was paid to hook up power to outlets. Verifying that the machine was set for the correct voltage is outside the scope of the electrician's responsibility as described in the original post.
Reply to
Doug Miller
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.
Reply to
StickThatInYourPipeAndSmokeIt
CNC machines are NOT 'house electrician' level work.
Where did you get the idea that this was a 'house installation'?
Reply to
StickThatInYourPipeAndSmokeIt
You're nuts. Maybe at the end of a 100 yard long run. Maybe.
There is no reason, however, for the entire feed to a building to sag that far between loaded and unloaded.
Reply to
StickThatInYourPipeAndSmokeIt
I cannot believe the remarks made by some in Usenet.
Contradict yourself within a single sentence often, idiot?
Reply to
StickThatInYourPipeAndSmokeIt

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