NFPA 70-2005
392.6 (E) Multiconductor Cables Rated 600 Volts or Less.
"Multiconductor cables rated 600 volts or less shall be permitted to be installed in the same cable tray."
Thanks for the info. on the multiconductor cable and Tray. Does anyone else know where I can find the same infomation for conduit? I was told I can't mix 300v and 600v cables in the same conduit even though the voltage is 24v for all cables.