Black/red/blue might be typically used for 120/208 rather than 277/480, but I don't think such use actually violates any article of the NEC.
I realize the use of black,red,blue for 277v does not nessecarly violate any code,but if 120v is already in the box and identified as black,red,blue, then using black,red,blue for 277v would be a violation