Corridor Lighting

The situation is a longish corridor, all lights are controlled by 2 switches - 3 way wired. I want to add a 3rd and maybe a 4th switch such that any switch can turn on all lights or turn off all lights.

Thanks in advance,
Brian

 

You can add as many as you want. At each new location, you need a new 4-way switch. There are two main options for wiring them:

(1) You can insert this new 4-way switch into any black/white/red cable in the lighting circuit, assuming there is enough slack in the cable. It isn't even particularly important to know where the wire is coming from or going to exactly, as long as it attaches to at least one of the 3-way switches. The connections will depend on how the cable is connected at the 3-way switch.

(2) If the new 4-way will not be near any of the existing cables, simply run two black/white cables between either 3-way switch to the 4-way switch. At the 4-way, attach one black/white pair to the "input" screws, and one black/white pair to the "output" screws. At the 3-way, disconnect the two wires from the traveler screws and attach them to one of the black/white pairs. Then connet the other black/white pair to the two just-vacated traveler screws. Remark both ends of the new white wires with black marker.

Post back with more information and we can provide more details.