US wire color coding clarification
In the USA, the National Electrical Code says:


Ground must be green, bare or green/yellow (that last a concession to EU harmonization.) 
Gray or white are neutral. 
Hot wires can be any other color, including blue.


The UL certification process will probably hold you to those colors.  There's no conceivable reason to approve a color violation when cables of the correct colors are readily available from our robust and competitive domestic cable industry. 

Now, you might be able to snake through a notched exception found in NEC 400.22c, which allows "light blue" for "jacketed cords furnished with appliances", but only if there are no white or gray wires.  I'm sure this is an EU harmonization thing, probably out of trade deals to avoid using wire colors as trade barriers.  I'm sure EU reciprocates, and allows white in the cord as neutral, if there are no blue wires in the bundle. 

Hot colors aren't mandatory, but certain colors are common practice.  


Black = first phase (i.e. most common cables are green-white-black)
Red = second phase (typically, 240 split-phase). 
Blue = third phase 
Brown-Orange-Yellow = alternate scheme for 3-phase, often to indicate a different voltage of 3-phase in a plant with several voltages. 
Blue-Yellow-Red = a rare alternate scheme for 3-phase, very common overseas
Purple-Pink-Black = 3-phase power in Prince's house. 


So -- Blue-Yellow-Red will suggest "a bit weird", and "3-phase delta".  That may not be the message you want to send. 

P.S. 3-phase power without a neutral is called "delta".  It's a perfectly fine and normal kind of 3-phase power widely used in industry.