The way I read it the Class has a big part in the two being able to be put together as well as the wiring methods. Now if you changed the power supply from a class 2 or 3 to a one that might be a different story.
See 725.52 (A) Exception 2 & fPN below
Class 1 rated output of Not more then 30 volts & 1000 volt amps.

Last edited by Yoopersup; 06/27/09 08:57 PM.