480V Panel Installed by DIY Homeowner

[GrrrrCxA]

Hey all, mechanical engineer here, looking for input from experienced electrical workers on if this situation constitutes a minor side-eye or a major red flag in terms of safety:

A personal acquaintance, who has done a decent amount of self-taught DIY electrical work in his home over the last decade or so, is also the owner of a small manufacturing business. Business needed a new air compressor, and a new 480V panel to serve it, which he decided to install himself. Work is completed already, no incident when first energized, so presumably he connected the wires in the right places and didn’t short anything out.

As an engineer who has worked near energized electrical equipment for most of my career (inspections, power measurement, equipment testing), but is definitively not qualified to perform electrical work directly, I have nonetheless had electrical safety trainings up the wazoo. The thought of doing work around a 480V panel installed by some DIYer with no experience beyond residential seems kinda concerning, and while I’m not likely to get anywhere near this guys work myself, his staff certainly are.

Curious if you all would consider this a potentially significant hazard, or just a “probably not the smartest move, but what’s done is done” sort of scenario. Thanks in advance for the input.

 

[petersonra]

I have found that a fair number of diy installations are done well, maybe better than the average pro, and certainly better than the average professional hack. Other diy jobs are a mess

It is not real hard to learn how to install just about anything electrical if you take the time to learn.

So I guess my answer is unless you have some specific issues in mind, it would be real hard to tell there is a problem or not.

Incidentally there is no particular difference between working on 120 volt installations versus 480 volt installations. The same rules apply so it is not like you are in a different world.

 

[LarryFine]

Incidentally there is no particular difference between working on 120 volt installations versus 480 volt installations. The same rules apply so it is not like you are in a different world.

But the ka-booms are much bigger!

 

[kwired]

Is it a 480 volt panel but supplied with 120/240?

Unless supplied with three phase you either have every other space useless or I have seen people jump one bus to another- leaving you with same line on two spaces and other line on every third space.

Also gets kind of expensive, unless he already had enough breakers available to fit his needs, and presuming he used the correct ones for each circuit.

Might be able to get a single phase 277/480 panel but would be kind of rare I would think.

I've had people that bought 3 phase QO panels at auction before, even unused but dirt cheap, wanting me to put them in their house, shop, etc. where they only had single phase.

 

[suemarkp]

If it is really 480/277V, about the only thing new compared to residential is the extra rules for grounding/bonding when over 250V. And maybe the rules for having different wire colors per voltage system. Was it inspected? I think here in WA, if you own it you can install its electrical yourself (home, business).

 

[tom baker]

Yes in WA the property owner or full time employees can do electrical work, but permits and inspections are required. A ground fault on 480/277 is more dangerous than 120/240 as the fault won’t clear and will continue to burn.
It would be a possible concern for your friends insurance company.

 

[GrrrrCxA]

But the ka-booms are much bigger!

View attachment 2568860

Haha, my concern exactly. It’s all good, if you did it right. If you didn’t…

 

[GrrrrCxA]

If it is really 480/277V, about the only thing new compared to residential is the extra rules for grounding/bonding when over 250V. And maybe the rules for having different wire colors per voltage system. Was it inspected? I think here in WA, if you own it you can install its electrical yourself (home, business).

Makes sense. No inspection was done so far as I’m aware.

 

[GrrrrCxA]

Yes in WA the property owner or full time employees can do electrical work, but permits and inspections are required. A ground fault on 480/277 is more dangerous than 120/240 as the fault won’t clear and will continue to burn.
It would be a possible concern for your friends insurance company.

Thanks appreciate the insight. Yeah I was thinking an inspection would most likely be the thing in order here, especially since it was his first time doing anything with 480. And insurance would not look kindly in it in the event that something did happen as a result of his workmanship if he had not followed the proper process

 

[busman]

If it is really 480/277V, about the only thing new compared to residential is the extra rules for grounding/bonding when over 250V. And maybe the rules for having different wire colors per voltage system. Was it inspected? I think here in WA, if you own it you can install its electrical yourself (home, business).

Well, most DIY never do 3-phase, so all of those rules would be new also. In addition, possibly an SDS which DIY rarely do.

Mark

 

[Eddie702]

Since everything works, I would be more concerned with bonding/grounding etc. Could be ok could have a lot of things wrong.

 

[kwired]

Is it a 480 volt panel but supplied with 120/240?

Unless supplied with three phase you either have every other space useless or I have seen people jump one bus to another- leaving you with same line on two spaces and other line on every third space.

Also gets kind of expensive, unless he already had enough breakers available to fit his needs, and presuming he used the correct ones for each circuit.

Might be able to get a single phase 277/480 panel but would be kind of rare I would think.

I've had people that bought 3 phase QO panels at auction before, even unused but dirt cheap, wanting me to put them in their house, shop, etc. where they only had single phase.

I guess when I posted this I thought he was installing 480 panel in his home, but now I see he installed it at the business he owns.

 

[electrofelon]

Was on a job once where a tenant installed a loadcenter panel at the end of a 480 feeder to serve some 480 welders and such. I kept my distance from that one.

 

[letgomywago]

Was on a job once where a tenant installed a loadcenter panel at the end of a 480 feeder to serve some 480 welders and such. I kept my distance from that one.

Was it an old school one where the ground bars are 1/4 inch from phases.

 

[electrofelon]

Was it an old school one where the ground bars are 1/4 inch from phases.

I think it was a sq D QO at least. If it was a Eaton BR/zinsco 2 I would have increased my clearance another 10 ft