I currently have a 3 way switch in the detached garage for the overhead lighting and a 3 way switch in the house so that I can shut off the lights from the house if I forget to turn them off. The wiring between the house and the garage is underground in pvc conduit with #14 THHN wiring. The conduit enters the garage and goes into a junction box where it is connected to nm cable that goes to the switch box. I am going to add a 4 way switch in between so that I can have another switch inside of the overhead door when I enter the garage that way. Instead of taking all of the wiring apart to rewire the 4 way switch into the middle of the run I was wondering if I can use 14/4 for the two sets of traveler wires from the junction box to the new location with the 4 way switch. The question is does this satisfy the requirements to have the entire circuit encased in the same cable or do I have to use two three wire cables and pass the common hot through the 4 way switch box?