It only requires rewiring the entire distro from three phase to single phase....which means it's no longer covered by the electrical certification sticker on it...
Would not recommend this. Contact them instead and see if they can make what you need, I'm sure it's a pretty common request.
But, if it's a design they've not built before, in order for it to be UL/ETL listed, they have to submit the design for approval, which costs money. So, if they haven't built a particular model (and had it certified) in the past, the cost to have them built it for you will probably be prohibitive, unless you're buying a bunch.
However, using the L21-30 I/O box and using a cable that takes the L14-30 and only powers two of the three legs (assuming you remember WHICH outlets are therefore hot!!) would suffice.
-Ray
