Another useful addition to my PDF document library—a home circuit map

If you live in a slightly older home, such as mine, you occasionally might want to know which circuit breaker or fuse controls a particular outlet. Besides making it more convenient to disable the power for repairs, some of us have to deal with easily overloaded circuits that weren’t meant for all of the modern gadgetry we depend on.

Every homeowner can benefit from having a good map to their home outlets and circuit breakers, and a PDF scan of this map can make it extremely convenient to find two years later when you forgot you ever made it.

My Map

Last week my wife was asking if she could run her Jiffy Steamer in the bathroom, or if it would trip the breaker. I remembered making my cheat sheet, so I simply brought up Spotlight on my Mac and typed in “home circuit” and was rewarded with this document:

It’s nothing fancy, but it gets the job done. I quickly scrolled to the bathroom and identified the circuit that she was using. A quick scroll through the other rooms showed that she would be safe as long as she turned off the air conditioner in the bedroom.

Making a Circuit Map

There’s a little bit of process involved here, and it helps if you have someone else to help you.

Get a notepad and scrawl a rough sketch of each room in your house that has electrical outlets, switches, and lights. Don’t forget the basement, garage, and attic. Draw a rough sketch of each electrical outlet/switch on the maps. You can see in the image above that I simply drew a little box for each outlet and a box with bumps on it for a set of switches.

Then, shut off a single breaker and go around the house to see everything that lost power. Take a small desk lamp with you or, better yet, a proper line voltage test light, and test every single outlet until you identify the ones that are off.

Every time you find an outlet or switch that is off, write the breaker number on its spot on your map. You can see that breaker 19a and breaker 7 both control the living room in my house.

Now turn that breaker on and then turn off the next breaker and repeat the whole process.

It may take ten or fifteen minutes to make the first round-trip, but with each new breaker you have fewer things to test. You really only need to test outlets or switches that have not been identified yet.

When you are done, scan in everything and give the file a nice long descriptive name. Throw in some keywords if you are indexing your files in some application.

Using the Circuit Map

If you are concerned about the load on a given circuit, you can go through the whole document and look for every matching number (such as the “19a” from my living room) to see how many devices are on that circuit.

If you need to shut down power to a switch or outlet for any reason, find its breaker on your map, shut off the breaker, and then test the outlet with your line voltage tester before you do anything else. Even though you know the right breaker, you must always double-check that the circuit is dead before performing work.

By the way, my wife has had that Jiffy Steamer for years, and she absolutely loves it—it probably ranks right next to her iPad as all-time coolest and most useful products.