Making sure your electrical outlets are functioning properly is essential to preventing problems ranging from short circuits to electrical fires. A number of issues, including problems at the outlet itself to bad wiring in your home, can cause an outlet to buzz. You can perform simple troubleshooting procedures yourself, but consult a certified electrician before making any changes to your home's wiring.
Bad Outlet or Receptacle
The deterioration of components within an electrical outlet is the most common reason an outlet will buzz. When you plug something into an outlet, contact blades within the outlet hold the plug in place. If these blades become loose or damaged, they don't maintain proper contact with the plug, which can cause buzzing. The simplest way to fix this problem is to have an electrician replace the electrical outlet. Outlets can be purchased for a few dollars from any hardware store. You can also have the electrician check the connections on an outlet to verify that the screws and wires are still making good contact.
Bad Fixture or Lamp
Bad electrical wiring within an electrical device can cause buzzing and humming that is unrelated the outlet. If you have a light fixture connected to the wall outlet, for example, the fixture itself might be causing the buzzing. Move the fixture to a different outlet to see if you can replicate the buzzing. If you can, the problem lies with the fixture rather than the outlet.
Dimmer Switches and Other Devices
Dimmer switches can often cause buzzing both at the light fixture and elsewhere if they share a circuit with other outlets. To determine whether a dimmer switch is causing the buzzing, turn the dimmer switch all the way off and listen for the sound at the outlet. If the buzzing stops when the dimmer switch is turned off, the dimmer switch may be the cause of the sound. Try replacing your current light bulb with a rough service bulb to see if this remedies the problem. If it doesn't, consider replacing the dimmer switch with a regular switch.
Devices can occasionally cause buzzing at other outlets that share the same circuit. If you're familiar with how your home is wired, unplug any other devices connected to outlets on the same circuit as the outlet that is buzzing. If the buzzing stops while these devices are unplugged, the outlet is likely functioning properly.
Issues with the wiring in your home can also cause buzzing to emanate from an outlet. Whether the wiring was improperly installed or has simply begun to fray or deteriorate with age, bad wiring can cause arcing and issues at the circuit breaker. If the solutions suggested previously don't remedy the buzzing sound, have a licensed electrician investigate the wiring in your home for damage, wear or bad connections.
Additional Information and Warnings
Always turn off power at the circuit breaker whenever you are working with an electrical outlet.
Troubleshooting and attempting to repair an electrical problem of this nature is a task best performed by a licensed professional.
Some ground fault circuit interrupters produce a slight humming noise, particularly when being reset.