Casa: Two Way Lights in the Stairway
While the main stairway coming from the great room to the forward upstairslanding is a glorious piece of American building craftsmanship, the rearstaircase is by contrast a dinky, dark and awful. It had no lighting at allwhen we moved in, so if nothing else in the interests of safety we decidedto remedy this as quick as possible.
Four months later.
Today, I elected to start wiring in the new lighting. Since I'd alreadysmashed holes in the plaster in order to run the new power bus up to theattic conversion, I had a nice source for power that I wasn't worried aboutoverloading with a couple of 40w lights.
The light fixtures I'm using I picked up from the garbage at work - they'remade for the "eyeball" type bulbs, but I'm reasonably sure that anythingthat won't overheat and trip the thermal should be okay. Since the stairwayis badly designed, a protruding bulb will lightly get either broken, orpeople will get burnt heads, since tall people (such as myself) come withina few inches of touching the ceiling with our heads in places.
I proceeded to smash more holes in the wall in order to route the cable. Istarted out by running some #12/2 from the bus to the first switch, but Ididn't hook it up to the bus just yet because I wanted to minimize theamount of time the power was off. As per the nifty schematic I drew up inXcircuit, I then ran some #12/3 between the two switch boxes (you guessedit, more holes in the wall).
Wiring Diagram for Two-Way Light Switch
It must be stressed that #12/3 or #14/3 wire is required for a two-wayswitch system (the wire size you use will depend on preference, budget, andyour local building code). /3 wire has three conductors and a ground, theextra wire is used for the "traveling" wire in this system. In myexperience, I have seen people (mostly working on electrical systems intrailers) using the ground wire for the traveling wire, but this is veryvery bad! Probably 50% of the time the traveling wire will be carryingmains voltage, and in most of the US #12 and #14 wires you buy, the groundwire doesn't have insulation. If you're stupid enough to wire your houselike this in order to save a few bucks on wire, I pity you.
That thought out of the way, I ran more #12/2 from the second switch to thefirst fixture, and from there down to where the second fixture will be. Wiring up as many fixtures as you like is a simple matter, simply hook them all up in parallel, jumping from one enclosure to the next. Be sure to keep your joins inside an enclosure (plastic or metal, it doesn't matter and they both have the same fire-snuffing characteristics, but plastic ones are cheaper) as per almost every county/city code I've seen. Put wire nuts on each join and cover in electrical tape if you're sure you won't be needing them again.
Finally, once everything was wired up, I disconnected the fuse for the bus I was working off (if you're unsure, I'd highly recommend removing all the fuses/breakers in your house while you're working on live wires) and connected the power to the new light circuit. After double-checking everything was correct, I put the fuse back in and checked it with some regular light bulbs.
It worked! But I was still a little concerned with the 40w maximum on the box, and the lowest bulb I could find around the house was a 60w regular bulb. A few days later on a grocery shopping trip, I found some bulbs specially made for recessed lighting which are 30w. They light up basically the same amount of area, but I can be reasonably sure the thermal protection won't trip.
Now all that's left to do is put back the Sheetrock that I brutally smashed apart.