it is perfectly legal to run different voltages in the same conduit according to the NEC. Keep in mind that the NEC sets the minium standards.I will run 120 240 volts in same conduit but WILL NOT run 120 /240 with 277/440 you may know you did it but a lot of the unsuspecting do not know it and can be hurt or burn up equipment so if at all possible keep them apart


MAY THE SUN SHINE ON YOUR FACE IN THE MORNING AND YOU AWAKE WITH A SMILE