Wednesday, October 26, 2011

Mapping the electrical fantastic

Over the past few years, we’ve created a basic electrical map of the house. So I know which circuit controls each light, each outlet, each switch. I can see ahead of time what will happen if I turn off a particular circuit breaker. There’s a great-looking circuit mapper tool for doing this quickly, but we did it the slow way: two people on phones, one plugs in an outlet tester and the other flips breakers until the outlet loses power. Write down the result, move on to the next outlet. Eventually I sketched each floor of the house in InDesign, put in all the lights, outlets, and switches in their approximate locations, and marked their circuit numbers on the map. The map could be improved: I could note the electrical loads of each outlet, the date each outlet was last (re)installed, who last did the connections, and which outlets are tamper-resistant. But as is, it’s been very helpful in the last round of electrical improvements to know which circuit breakers to turn off, which circuits could be extended, and where a short-circuit might be.

In the last 6 weeks we’ve added 2 ceiling fans and switches, removed two wall sconces, and added outdoor outlets in two locations, a front porch outlet, basement outlets in two locations, and a lot of outlets in two upstairs bedrooms. We’ve upgraded numerous other outlets in the process to tamper-resistant or GFI, upgraded a couple more circuit breakers to arc-fault, replaced our outdoor lights, and done some other electrical clean-up. Oh, and we have a doorbell outside our house if you want to come visit!

What the map doesn’t show, though, is the circuits themselves: the paths of the wires to get from the main panel to their various receptacles and fixtures. And that’s become an issue as we try to figure out how to replace a few short runs of wire partially buried in the walls. The tone generator and wire tracer aren’t working to tell me where the wires go once they disappear behind plaster and lath. I suddenly find myself a fan of surface-run wiring.

So I spent an hour yesterday following circuit #1 around our basement, and another hour trying to figure out how to figure it out. Seven junction boxes, most splitting the circuit into two or three directions, and eventually seven runs of wire heading up to the first or second floor. Four of the runs are obvious: they go up directly below a first floor outlet on that circuit. But three of the runs are completely mysterious: they head up nowhere near a corresponding destination. And even worse, there are only two items on circuit #1 which are unaccounted for: a key dining room outlet, and a wall sconce and outlet on the second floor which are clearly fed by the same run. At least one run heading upstairs cannot possibly be going anywhere good. Two of the mystery runs come from a junction box helpfully mounted directly over our furnace, so they cannot be disconnected without removing the furnace.

I have a start: I’ve laid out the basement spaghetti of circuit #1 on our map. (This will be a good exercise for me to learn how InDesign handles layers.) Of course, this fall was supposed to be about finishing house projects, not starting them, so a start doesn’t really feel like progress.

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