Hi Douglas.
In the U.S.A. this is allowed within the NEC ( national electrical code) provided that all wires have insulation rated to the highest voltage i.e. 300 volt insulation and that splices of the different systems are physically seperated via seperators within junction boxes or made in seperate junction boxes.
There will be no problems with induced voltages etc.
Victor Creazzi
Aerofire Windpower