Electrical Wiring in the Home/Mystified About "Legs"


When I moved into my house, built in 1920 and rehabbed in the late 1990s, I wanted to set up an intercom between my office upstairs and my husband's office downstairs -- one of those intercoms whose units communicate with each other through the house's wiring. I could never make it work. The rehabber went into great detail about how the two rooms were on two different "legs," and that was why units that were 10 vertical feet and 20 horizontal feet apart couldn't communicate with each other. I nodded and pretended to understand, but I still don't, and I don't know enough for Googling to do any good. Can you explain it to me in baby-talk?

You have 2 hot wires and one neutral that comes into the house.  Each of the hot wires controls half of 110 volt breakers. This is called a leg.  Since the wires do not connect to each other, it is hard for anything to communicate, because the signal has to go back to the transformer on the pole or ground.  It may be possible to change the legs by switching breakers of the same amperage. But everything has to be relatively balanced (you can't have 3/4 of your circuits on one leg)  Every other breaker vertically is on the same leg. This includes the breakers that are next to it on the side. If you have any 220 volt appliances, the intercom may work when something is turned on, such as the stove.
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Electrical Wiring in the Home

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Bob Sponaugle


Just about any home wiring question. (not appliance repair) I have done all kinds of home wiring for myself, including adding a new breaker box, etc. Please, questions from North America only. Please be specific with details.

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