480V to a 120v Load

[wmeek]

I have a customer that has plugged a generator into a trailer used for testing. The problem here is the generator switch was on 277/480 an should have been on 120/240. I was wanting to see what others think about the existing wiring an the panelboard an breakers. What all should be changed out. I am headed over this afternoon to check it out an wanted to see what other things to look for.

 

[GoldDigger]

I have a customer that has plugged a generator into a trailer used for testing. The problem here is the generator switch was on 277/480 an should have been on 120/240. I was wanting to see what others think about the existing wiring an the panelboard an breakers. What all should be changed out. I am headed over this afternoon to check it out an wanted to see what other things to look for.

IMHO, it is not very likely that the wiring itself is damaged, since it would be insulated to 600V and would be protected against overcurrent.
As for the panelboard itself, probably OK too and any damage should be visible on inspection after removing all the breakers.
Any active devices such as breakers might have been damaged by opening against a voltage greater than their rating and things like shunt trip coils or active circuitry in an AFCI or GFCI breaker might be compromised too. Check with the manufacturer if uncertain.

 

[templdl]

IMHO, it is not very likely that the wiring itself is damaged, since it would be insulated to 600V and would be protected against overcurrent.
As for the panelboard itself, probably OK too and any damage should be visible on inspection after removing all the breakers.
Any active devices such as breakers might have been damaged by opening against a voltage greater than their rating and things like shunt trip coils or active circuitry in an AFCI or GFCI breaker might be compromised too. Check with the manufacturer if uncertain.

Just going by the OP's description of the generator being 277/480 which is a 1ph voltage which I understand to be accurate I could see where it would have been possible to connect it to a 120/240 1ph 3w panel. I would have expected that the generator was 480y/277 3ph4w which would have taken a bit of effort to connect to a 120/240 1ph3ph panel. If for some reason it was done and I don't how it could be accomplished, the breakers in the panel would have been rated 120, 120/240 or 240v max.
Whoever attempted to do this is far from being qualified.

 

[wmeek]

It only knocked out a control transformer on the AC . Not sure what voltage was put to it as the generator was not on site . All ballast were good. Would a Surge protector help prevent damaging the equipment if it was hooked up wrong again
with a wrong voltage.

 

[jumper]

Whoever attempted to do this is far from being qualified.

Sorry,,, I was in a hurry.