A dead-end threeway is a wiring method that takes a little bit of understanding of how three-way switches work in general. The difference between a dead-end three-way and a normal three-way switch setup is in the wiring at each end of the scenario. With a standard three-way, you’d have a hot coming into one box on one side of a hall, with the switch leg coming out of the other box on the other side of the hall. This allows us to run travelers between the boxes for the three-way to work. With a dead-end three-way, everything comes into and leaves the first box. Our incoming hot and our outgoing switch leg are in the same box on one side of the hallway. To get another switch at the other end of the hall, we’d have to get 3 conductors over to the other box for the other 3way switch to hook up to.