Wye panel on a Delta system.

[Mr. Bill]

Are there any Code or UL listing issues by using a 277Y/480V panel on a 480V delta system?

A follow up question. Any Code issues having a 480V, 1-phase load on a 480V, delta system?

Thanks for the help.

 

[augie47]

My understanding is that it is not a violation as the panel is not listed for the voltages being used.

 

[xformer]

My understanding is that it is not a violation as the panel is not listed for the voltages being used.

If it is not listed for the voltages being used, would that make it a violation??

 

[augie47]

thanks... one day I will proof-read... "is a violation".. the "not" snuck in there.,

 

[kingpb]

A 480V 3 phase panel fed from a 480Y/277V (wye source) where the neutral is not brought to the panel require a lower insulation system.

A 480V 3 phase Delta system requires a higher insulation system because if one leg goes to ground, the voltage on that phase can go to at least sqrt 3 times the phase voltage.

Hence you will see that 3ph, 3wire 480V Delta will have a 600Vac maximum rating whereas a 480Y/277V will have maybe only a 480V maximum rating.