Transformer feed ( One size smaller )

[Davebones]

Is there a issue if one conductor feeding a 3 phase transformer ( 480 - 120 208v ) is one size smaller than the other two phases as long as it's rated for the primary fuse size ? Is there a code prohibiting this ?

 

[infinity]

As long as the condcutors are protected at or below their ampacity there is no issue. Any particular reason why you would do this?

 

[petersonra]

Is there a issue if one conductor feeding a 3 phase transformer ( 480 - 120 208v ) is one size smaller than the other two phases as long as it's rated for the primary fuse size ? Is there a code prohibiting this ?

I don't recall anything in the code would prohibit this, as long as the conductor is properly protected.

A little unusual though.

I suppose it could get small enough that it would not meet the minimum size for the calculated load. That would be a code problem.

 

[Davebones]

We have some left over over cable we were looking at using to install the transformer .

 

[topgone]

Is there a issue if one conductor feeding a 3 phase transformer ( 480 - 120 208v ) is one size smaller than the other two phases as long as it's rated for the primary fuse size ? Is there a code prohibiting this ?

What what are your transformer loads? If you have motor loads, you have to be aware that there are limitations as to the voltage imbalance to prevent excessive motor heating. The motor temperature will increase to twice the square of the voltage percent imbalance (2 degrees C for 1% imbalance; 8 degrees C for 2%, etc).