Start every electrical project with the most important safety measure—de-energizing the wires and devices you're working on. We'll show you how to make sure the power to your home circuits has been turned off. Our information will also help you know what to do when receptacles or lights suddenly go dead, which may indicate that a circuit has overloaded.
Start at the Service Panel
A residential main service panel contains either circuit breakers or fuses and is usually located in a utility area. It should be easily accessible but away from the main traffic flow in the house.
The panel may be in the garage or basement. In warm climates it may be on the outside of the house. In an apartment or condo, it may be recessed into the wall in a closet or laundry area. The service panel probably is a gray metal box or door, unless it has been painted.
You may find more than one service panel, especially in an older home. Subpanels are sometimes added to older systems to expand the number of circuits. De-energize these just as you would a fuse or breaker in a main service panel.
You may need to get at the panel in the dark or in a hurry during an emergency. Make sure all adults in your home know where to find the panel. Keep the path to the panel clear and don't lean things against it.
Open the door to get to the fuses or breakers inside. If the panel appears damaged or if loose wires are visible, call a professional electrician to check it.
Examine the Breaker Box
After opening the service panel door, you will find rows of individual circuit breakers, which look like toggle switches, and a main breaker on top. A list indicates which parts of the house each breaker controls.
The list should identify which breaker controls the receptacle or fixture you want to de-energize. These are individual breakers. To shut one off, flip the lever to the "off" position. Test the device to make sure power is off before working on it.
To turn off power to the entire house, flip off the main breaker, usually a double-width switch located at the top of the service panel. You may need to have a flashlight handy when you turn off power.
Other Types of Circuit Breakers
Breakers vary in the way they shut off when they sense an overload. One toggle type has a red button that pops up when the breaker has tripped. Reactivate it by turning the switch back on. Some toggles turn partway off when they blow. To restore power, flip the switch all the way off, then on. The button on a push-button breaker pops out when the breaker shuts off; push the button in to restore power.