Panel Voltage Rating

[ASG]

I'm working on a job that had special 230V equipment so I showed a transformer to a new 230V 3 phase panel to feed this equipment. The contractor is now asking due to lead times if they can use a panel rated for a different voltage (240, 480) so they he can get the panel quicker. Is there any code violation or other issue here?

 

[ptonsparky]

I would call for the 240, but there may be more details that need to be known.

 

[ron]

The nominal voltage for a 230V load is 240V. I would also accept 480V or 600V.

 

[raberding]

The nominal voltage for a 230V load is 240V. I would also accept 480V or 600V.

every day. You take whatever you can get these days

 

[infinity]

Are there panel specifically listed for 230 volts?

 

[ASG]

Sounds good. I've seen 480V panels being used for 208V power before but, as we all know, just because you see it in the field doesn't mean it's safe or code compliant

 

[mbednarik]

The panel just needs to be rated for the nominal voltage or above. Watch out for corner grounded systems, they will be a high rating due to the higher voltage to ground.

 

[infinity]

The panel just needs to be rated for the nominal voltage or above. Watch out for corner grounded systems, they will be a high rating due to the higher voltage to ground.

Are you saying that it will be higher than the line voltage? Would the panel need to be marked as allowing a higher voltage to ground?

 

[jim dungar]

The panel just needs to be rated for the nominal voltage or above. Watch out for corner grounded systems, they will be a high rating due to the higher voltage to ground.

No.
On three-phase systems:
Corner grounded systems have all the same L-G voltages.
High leg, or center tap, or wild leg, have one L-G voltage higher than the other two.

 

[ptonsparky]

I don't think corner grounded systems all have the same L-G voltages. All I've ever seen, one phase was 0v to ground.

 

[Charged]

I thought one L-G was 208v on a 240v corner grounded delta system . I never thought about that, if that’s true , a 240/120v panel isn’t rated enough ?

 

[jim dungar]

I thought one L-G was 208v on a 240v corner grounded delta system . I never thought about that, if that’s true , a 240/120v panel isn’t rated enough ?

The 208V occurs on a wild leg system, not on a corner ground.it is important to understand these are two different animals.

Yes panels and their breakers, need to be rated for the maximum L-G voltages. However while most panelboard bussing is insulated at 240V L-G, most residential and commercial breakers aren't.

 

[Charged]

The 208V occurs on a wild leg system, not on a corner ground.it is important to understand these are two different animals.

Yes panels and their breakers, need to be rated for the maximum L-G voltages. However while most panelboard bussing is insulated at 240V L-G, most residential and commercial breakers aren't.

Thanks for the clarification. Are both of these usually delivered by a bank of pole mount transformers?. I seem to recall, a bank of three with one larger is a clue on one of them. Thanks

 

[jim dungar]

Thanks for the clarification. Are both of these usually delivered by a bank of pole mount transformers?. I seem to recall, a bank of three with one larger is a clue on one of them. Thanks

Yes, they can look similar. They can both be made using a bank of only two transformers.

Mismatched transformer sizes are extremely common with the 240/120V 3 phase 4 wire, wild-leg/high-leg/bastard-leg/center-tap, system.