Make It Permanent
There are a few ways to make circuit breaker labels clear and permanent. You can make nice, neat, black-and-white labels with a label maker. Some electricians do this (and wouldn’t you like to find one of them for house calls?). Another option is to create a grid on a sheet of heavy paper and slip the paper into a clear plastic sleeve stuck to the inside of the breaker box door. Or, you can cut to the chase and use a permanent marker, writing directly on the metal panel next to each breaker. Lots of electricians do this. Unfortunately, not so many have legible handwriting. If yours isn’t so hot, either, perhaps a printed option is better.
Don’t Use Nicknames
Chances are you won’t live in your current house forever. And even if you do, someday the house will change hands, or someone who isn’t a family member will need to use the breaker box, or whatever. Do everyone a favor and don’t create circuit breaker labels with notes like “Mom’s workroom” or “Nursery.” Instead, think about universally meaningful notation, such as “N.E. Bedroom” and “Garage Outlets.” Your panel may have a few spare breakers that aren’t connected to any circuits. If so, label these as “Spare” so you’ll know not to bother with them when searching for the right breaker.
Mapping Your Circuits
Now comes the fun part. If any of your breakers are already labeled, they’re probably breakers for the big circuits, such as those for the dryer and range, and perhaps all of the dedicated circuits, individual circuits that supply only one appliance each. If you switch off a breaker and discover only the fridge is not working, you’ve found its dedicated circuit. One clue to circuit sleuthing is the amperage (amp) rating of the circuit. This is the number printed on the circuit toggle lever or nearby. There are common amp ratings for various appliances and devices; if an appliance is rated for 20 amps, for example, you’ll know it’s not powered by a 15-amp circuit (or at least it shouldn’t be).
Kitchen outlets: 20-ampRange/oven/cooktop: 30-, 40-, or 50-ampDryer: 30-ampGarage outlets: 20-ampMicrowave: 20-ampLaundry outlet/washer: 20-ampRoom air conditioner: 30-ampBathroom vent fan with heater: 20-amp or moreLighting, general receptacles, etc.: 15-ampCentral A/C: 30-, 40-, or 50-ampHeating system (inside unit): 40-, 50-, or 60-ampDining room outlets: 20-ampBathroom outlets: 20-amp
Finding circuits that aren’t marked is simple: Turn on anything you can, then switch off each breaker one at a time and see what turns off in the house. With large appliances, a digital clock or interior light on the appliance is an easy giveaway. To check outlets, use a non-contact voltage tester, the safest and easiest device for checking for power. Just stick the probe of the tester into each outlet slot; if the tester lights up, the outlet still has power. Note everything that’s on the circuit and transfer your findings to the directory or the individual circuit.
