My garage lights are currently controlled via two 3-way switches (one at the top of the stairs, one at the bottom). I'd like to add another 4-way switch so I can control the lights from the other end of the garage.
I understand how to do the electrical part (how to setup the circuit), my question is more about the materials and permitting aspects of this work. I live in San Francisco, so if someone happens to know the actual permit guidelines for this area, I'd be much appreciative.
My original plan was to run a 12 or 14 gage armored cable from the bottom 3-way switch, along the top of the garage (under the floor joists), to the other end of the garage, where I'd install the new 4-way switch. As I was picking out the armored cable at Home Depot, the sales guy told me that armored cable is not allowed in San Francisco garages, and I would need to use plastic-clad wire inside a pipe conduit. This seems like a huge pain, is it true?
I tried to read the San Francisco electrical code, but it's very hard to follow. The electrical code seems to allow "armored cable AC" but is more restrictive about "metal-clad cable MC", but I can't quite figure out the difference between them. Further, the code seems to care about such cable being installed in "wet areas", but the top of my garage isn't wet by any stretch of the imagination. Looking at the existing conduit in my garage, most of it is run in metal tubes, but there are occasional short runs of armored cable, although I'm not sure how old they are (they could be from before the electrical code changed?).
Also, would I need to get permit for this kind of work? It seems like such a simple project. The lights that this new switch would control consume around 200W (2 neon tubes), so this isn't a big circuit by any stretch of the imagination.