I'm rewiring my unfinished basement. It has two entrances – a cellar door to the outside and the normal staircase in the house. Even though it is unfinished, the basement is kind of divided into different rooms. I want each "room" to have its own light and light switch. I also want to be able to kill all of the lights at once from the top of my stairs and also re-energize the whole circuit if I happen to walk in through the cellar door. Please tell me whether the following plan is safe and workable:
I'll start with a fairly normal 3 way switch setup. Picture one switch on the left, next switch in the middle, and the light on the right. This light is the one over my stairs, and it will work off of the 3 way switch like you would normally expect. Power from the breaker box can go into the middle switch or the light on the right – either way is easy enough. Once that is all set up I splice a 2 + ground cable to the hot and neutral on the light and run it to the next light, except I wire that second light to its own 2 way switch. From there I continue the circuit until I have 6 or 7 lights with each of them controlled by its own 2 pole switch. If the kids leave 2 or 3 of those lights on, then instead of walking through the whole basement to turn them off, I can just flip the three way switch at the top of my stairs to kill the entire basement lighting circuit. The next time someone enters the basement from either door, they hit the 3 way switch and all of the lights that the kids left on come on again (plus the stairway light turns on because the 3 way is the only switch connected to it). Of course, none of the lights in the basement would work unless that 3 way switch circuit is closed.
Is all of this safe and up to code?
Best Answer
The Setup
To achieve what you want, you'll simply have to wire all the light circuits in parallel off the common of the 3-way. Basically instead of a light on the common, you'll have light circuits. Something like this.
Following this scheme, each single pole switch will control the lights in a single area. While the whole circuit, is controlled by the 3-way switches. This way, if the 3-ways are OFF all the lights will be off. If the 3-ways are ON, the individual single pole switches will determine which lights are on.
The down side
While this configuration is possible, it may be confusing to any future owners of the home. This may also cause problems if the area is ever finished and actually divided into separate spaces, since a somebody could potentially be lost in the dark.
Code compliance
I'm not sure at this point whether or not this setup is code compliant, but a quick call to your local government should yield the answer. I will continue to review the National Electrical Code (NEC), to determine if there are any sections that would not allow a setup like this. If I find any restrictions, I will update this section of the answer.
If any others happen to know any codes that might apply here, please post the code section as a comment.