That I do not know. All I can offer is that if you reverse any two, the motor will spin in the opposite direction. Perhaps it has something to do with physical positioning. If, for example, the three connections are in a straight line, then L1 and L2 are next to each other, and L2 and L3 are next to each other, but to swap L1 and L3 you have to move both sets of wires past L2. That might make the job a bit harder to do, and might make the final connections look a bit ugly. That is my best guess.
Originally Posted by Stevareno
Charles E. Beck, P.E., Seattle
Comments based on 2008 NEC unless otherwise noted.