What Causes an Electrical Switch to Flicker or Buzz?

If your light switch is making noise or your lights are flickering, it usually comes down to one of four common problems. Knowing what these issues are can help you figure out whether it’s a simple fix or a situation where you should call a professional electrician for assistance.

Reasons Why an Electrical Switch Might Flicker or Buzz

Here are the major causes of a flickering or buzzing electrical switch:

Electrical Arcing

If you hear buzzing, crackling, or popping sounds from a switch, it may be caused by electrical arcing. This happens when electricity jumps across a small gap instead of flowing smoothly through a wire.

Electricity always looks for the easiest path. If a switch is worn out or a wire is loose, the current can jump through the air to complete the circuit. This creates a lot of heat and can melt plastic parts or start a fire in nearby materials.

If your switch is making crackling noises or feels hot when you touch it, turn off the power at the circuit breaker right away. This is a serious fire risk.

Dimmer Switches and Bulbs That Don’t Match

If the buzzing or flickering only happens when you use a dimmer, the problem is probably that the switch and bulb are not compatible.

Older dimmer switches were made for incandescent bulbs. New LED bulbs use much less power and need special LED-compatible dimmers. When an old dimmer is used with an LED bulb, the following problems can happen:

• Humming: The dimmer reduces brightness by quickly cutting the power on and off. This can cause parts inside the LED bulb to vibrate, which creates a humming noise.
• Flickering: At low settings, the bulb may not get steady power, causing it to flicker or flash.

Make sure your bulbs say “dimmable” on the package and consider replacing the dimmer switch with one designed for LEDs.

Loose or Damaged Wiring

Over time, normal house movement or repeated use of a switch can loosen the screws that hold wires in place.

Loose wires cause an unstable electrical connection. This can make lights flicker as the power flow changes. It can also cause buzzing sounds as electricity struggles to move through the connection. Signs of loose wiring include:

• Lights that flicker when you touch or move the switch
• A switch plate that feels warm or looks darkened or burned
• A light burning smell, like plastic or ozone

Normal Aging and Wear

Light switches have moving parts inside them. Each switch contains small metal pieces and springs that connect the electricity when you flip it. After many years, often 20 to 30, these parts wear out.

When this happens, the switch may feel soft or loose instead of clicking firmly. Worn-out parts don’t make strong connections, which can lead to flickering lights and buzzing sounds.

When to Call an Electrician

Changing a light bulb is safe, but opening a switch box exposes live electrical wires. You should contact a licensed electrician if:

• The switch feels hot
• You see smoke or burn marks
• The buzzing continues after replacing the bulb
• You hear a loud pop and smell something burning

Closing Note

Ignoring a noisy or flickering switch can turn a small problem into a serious fire hazard. Watch for these major signs mentioned above. If you’re unsure, turn off the breaker and get a professional to have it inspected.

Contact our licensed electricians at Finch Electrical Heating & Air for electrical switch repairs. Call us at (651) 243-4711 today!