How to Determine which Circuit Breaker Controls Which Light or Outlet in Your House

Problem: You need to do some electrical work on a particular outlet, switch or light fixture in your house. You know the first thing you are supposed to do is shut off the circuit breaker to that device. But, which breaker is the correct one.

Solution: Head out to the main electrical panel, open the outside cover and there you see 20 – 30 or more circuit breakers. Don’t panic, on the backside of the panel cover there is a list by number of the breakers. Next to each breaker number is a description of each circuit and what it controls. This of course is a best case scenario. There may be minimal descriptions – such as “lighting” or “outlets” with a line running up and down covering 3, 4, 5 or more breakers. Sometimes there is nothing written on this list.

Rather than turning off all “lighting” circuit breakers you should identify and mark these circuits. To do this you will need a helper. Each of you grab your cellular phones, and with you at the breaker box and your helper inside, set up communication. Have your helper go to the device that you want to work on (outlet, switched light fixture, etc.). If you are working on an outlet, plug a lamp or radio (turned on) into the outlet and make sure the outlet is live. If the outlet is switched, turn on the switch so the outlet is live. If you are working on a wall sconce, or any type of recessed lighting (lighting that is not plugged into an outlet), make sure the light fixture is turned on. Now while you have communications with your helper, turn off breakers – in order – one at a time until your helper reports the light (or radio) has gone out. By using a radio plugged into an outlet, you can do this by yourself by turning up the volume and opening the doors and windows. Once you have identified the circuit you want to label it on the chart next to its breaker number. You can do the same for the other breakers so you won’t have to do this in the future.

NOTE: You can eliminate several breakers by using the following information. Outlet and lighting circuit breakers will be either “15” AMP or “20” AMP designated breakers. Ganged breakers (two breakers tied together at their switches), and breakers larger an “20” AMP will not be used for electrical outlets or lighting circuits. SAFETY NOTE: Once you have identified and turned off the circuit breaker, double check with a multi-meter to verify that the power is out. See the section, "How to use a Multi-Meter" on this website. h..