Single Phase panel install on 480

[Fordean]

I have a job, Was to wire a 3 phase compressor to a existing panel. I inspected panel and found spacing available.
But when we opened panel. We noticed they used a 3 phase 100 amp breaker, And Step down Transformer and ran a conduit 230 feet with Aluminum xhhw to rear of warehouse.
I presumed this to be a 3 phase panel when the owner asked that he would like compressor next to it. It is a 200 amp single phase.
I am going to explain to owner, That this particular system should be changed to 3 phase. For the Unbalanced nature of the install.
Am I correct in doing so, As far as a hazard is in effect.?

 

[kwired]

Did they step down on supply end or load end of the long run?

 

[Fordean]

Main 1200 amp 480 service 5 feet to single phase step down, from trans 2 feet to single phse 200 amp disconnect Then 230 feet to MLO panel with aluminum 4/0

 

[retirede]

Need more info. Presuming the compressor is being installed near the single phase panel. If it’s a 3 phase compressor, you need to either get the panel up to 3 phase or run new circuit from the main panel to the compressor. What voltage is the compressor? If the voltage is appropriate, is the transformer large enough to run the compressor plus its current loads?

 

[Fordean]

Need more info. Presuming the compressor is being installed near the single phase panel. If it’s a 3 phase compressor, you need to either get the panel up to 3 phase or run new circuit from the main panel to the compressor. What voltage is the compressor? If the voltage is appropriate, is the transformer large enough to run the compressor plus its current loads?

I am not concerned about the compressor. Should have excluded it. I can move the compressor. But I am going to change the panel to 3 phase if the Unbalance I feel will happen from only running a 1 phase panel. They easily could of installed a 3 phase panel.

 

[petersonra]

I have a job, Was to wire a 3 phase compressor to a existing panel. I inspected panel and found spacing available.
But when we opened panel. We noticed they used a 3 phase 100 amp breaker, And Step down Transformer and ran a conduit 230 feet with Aluminum xhhw to rear of warehouse.
I presumed this to be a 3 phase panel when the owner asked that he would like compressor next to it. It is a 200 amp single phase.
I am going to explain to owner, That this particular system should be changed to 3 phase. For the Unbalanced nature of the install.
Am I correct in doing so, As far as a hazard is in effect.?

I doubt it matters all that much. It certainly does not introduce any special hazard.

 

[retirede]

I am not concerned about the compressor. Should have excluded it. I can move the compressor. But I am going to change the panel to 3 phase if the Unbalance I feel will happen from only running a 1 phase panel. They easily could of installed a 3 phase panel.

There will always be some level of imbalance when powering single phase loads on a 3 phase system. Unless there is evidence of some adverse effects, I wouldn’t change anything.

 

[augie47]

It's a very odd install if the panel is the only load on the transformer but if your only concern is unbalance I would not worry.

 

[Fordean]

It's a very odd install if the panel is the only load on the transformer but if your only concern is unbalance I would not worry.

There will always be some level of imbalance when powering single phase loads on a 3 phase system. Unless there is evidence of some adverse effects, I wouldn’t change anything.

I will leave the 1 phase panel alone, If we are not worried about a unbalance. I figured it may be a hazard. Or just a poor design.
I will move compressor by the Main service. And speak to client if they want to change panel to 3 phase. It's a highly industrial type of building. I wouldn't have figured the panel to be 1 phase. Until I moved compressor over to it. Sucked to find out.

 

[infinity]

I see no reason for concern either. What is this 1Ø load on the 1200 amp service 50-60 amps? Percentage wise the imbalance is negligible that is if there even is one. There could be other 1Ø loads that would balance it out anyway.

 

[Fordean]

I see no reason for concern either. What is this 1Ø load on the 1200 amp service 50-60 amps? Percentage wise the imbalance is negligible that is if there even is one. There could be other 1Ø loads that would balance it out anyway.

The load on this probably 50 amp to 60. Only thing they can run are light equipment. Off of this. Real bad idea to run this in a industrial setting.

 

[electrofelon]

The load on this probably 50 amp to 60. Only thing they can run are light equipment. Off of this. Real bad idea to run this in a industrial setting.

I don't see that it's a bad idea if it does what is needed. Sure a 200 amp 3 phase feed and panel could feed more stuff, seems that's a question for the person writing the check if they want that. What's weird to me is they put the step down transformer at the start of the wire run....

 

[augie47]

I don't see that it's a bad idea if it does what is needed. Sure a 200 amp 3 phase feed and panel could feed more stuff, seems that's a question for the person writing the check if they want that. What's weird to me is they put the step down transformer at the start of the wire run....

That was my thinking in Post #8 ("odd install") bit, not knowing the details, I assumed there might be a reason.

 

[Fordean]

That was my thinking in Post #8 ("odd install") bit, not knowing the details, I assumed there might be a reason.

They put the Main service and Transformer is a wooden shed type. This place did waste disposal before our client. There must have be a huge moisture environment. Because Emt and troughs, Breakers are rusted. Probably worst I've seen. I am not sure if a chemical was involved as well.