What Causes an Electric Outlet to Spark When You Plug in an Appliance?

John Stevens J.D.

Residential electrical outlets have no moving parts and usually last for several years without requiring attention, but problems do eventually develop. Perhaps the most troubling problem occurs when an electrical outlet sparks, buzzes or is warm to the touch when an appliance is plugged into or out of the outlet.

A sparking outlet poses a serious risk of fire that should be addressed immediately.

The cause of the problem may only be an overloaded circuit or a loose or dirty wiring connection. However, repeatedly plugging and unplugging appliances can wear down the metal contacts inside of the outlet, in which case the outlet must be replaced.

Overloaded Circuit

Homes have several electrical circuits that run throughout the structure. These circuits all tie into the main service panel. When electricity is needed at one circuit, the main service panel sends the power through that specific circuit to the wall outlet. The power flows through the outlet and back to the service panel. If too much power is drawn through a circuit, the circuit will overload. Using one or more electrical power strips along the same circuit will frequently overload that circuit, so use power strips sparingly. If possible, move some power supply cords to different outlets.

Loose Wiring Connections

Inside of the wall and attached to the sides of the electrical outlet are several wires. Each wire is secured to the outlet with an individual securing screw that is tightened over the wire. If one or more of these screws has become loose, the outlet may produce a spark when a cord is plugged into the outlet. Tightening the screws will probably solve the problem, but the power must be turned off before you can safely remove the outlet and tighten the screws. Turn the main power switch off at the service panel, and remove the plate that covers the front of the outlet. Remove the two screws that hold the outlet within the wall, and gently lift the outlet out of the wall to access the screws on the side of the outlet. If the securing screws or metal terminals on the sides of the outlet are scorched, you should replace the outlet.

Dirty Wire Tips

If the wires are secured tightly to the sides of the outlet, yet the outlet still sparks when you plug a cord in, you should inspect the exposed tip of each wire for dirt and grime. A clean wire should appear shiny; a dirty wire will not produce a constant supply of power to the outlet, thereby causing the sparking problem. Pull the outlet out of the wall after turning the main power off. Remove one wire from the side of the outlet, and clean the tip of the wire with fine-grade sandpaper. Tighten the wire onto the outlet, and move the remaining wires. You should remove only one wire at a time to avoid confusing the position of each wire.

Defective Outlet

When the outlet still sparks after ensuring that the circuit is not overloaded and the wires are clean and secured tightly against the outlet, chances are good that the outlet must be replaced. Do not forget to turn the main power off before handling the outlet. Because all of the wires attached to the defective outlet must be removed, mark the position of each wire before removing it. Several color designations may be stamped into the back of the outlet. These designations refer to the color of each wire. If the replacement outlet has the same color designations stamped into the back of it, attach each wire to its respective terminal. If the new outlet does not feature color designations, or if the designations do not match the color of the wires, you should call a professional electrician to handle the installation to ensure that the outlet is installed properly.