Know Your Circuits with a Circuit Map

Electricians follow the minimalist school of writing: They write as little as possible when listing the circuits on the form inside the service panel door. An electrician will write “Lighting circuits,” for example, across the space designating one or two specific breakers. That’s all well and good, but a more useful description would say, “Ceiling lights in master bedroom and north bedroom, in second-floor hallway, and at top of stairs.” These written descriptions need more room than most factory-supplied lists provide, unless the writing is very small.

In a new house, the electrician’s list usually is adequate because the wiring is so straightforward. In an old house, however, the list needs to be more specific, especially if past homeowners have added their own electrical marks when they lived in your home. Every owner has different needs, and they manifest themselves with receptacles, lights, and switches in places that will make no apparent sense to you but are perfectly logical for someone else. These include lights in crawl spaces, switches on attic rafters, and receptacles in closets. You don’t need to know their history, but you should know which fuse or circuit breaker controls them, especially if they are tied in to the middle of a circuit and can potentially cause problems. Drawing your own circuit map can be done alone, but it is best done with some helping hands. To come up with your map, you’ll need the following:

• Paper and pen for recording
• Lights and radios to plug into receptacles
• Extra people spread around your house