Three Phase Circuit Serving Single Phase Transformer

[9212]

I have a client who wants to use 2 phases of an existing 3 phase 480V circuit to serve a single phase 480V/120/240V dry type transformer/panel (Square D, ?Power Zone?). The 480V breaker for the circuit is 30A, 3 phase. The circuit does not serve any other load. He has asked me to provide specific code information on why that is not allowed. While I?m pretty sure it is there, I cannot find a specific section dealing with the issue. Can anyone point me to it?

 

[Dennis Alwon]

IMO, there is nothing in the NEC that states you can't do this. The only issue is whether this is an issue with balancing the load in the panel. At 30 amps it is probably not a problem.