Quick answer: A faint hum from a transformer, doorbell, or some dimmers can be normal. Buzzing, crackling, or sizzling from a breaker panel, outlet, or regular switch is not normal and can indicate loose connections, a failing breaker, or arcing. Stop using the affected circuit, keep people away from the panel, and call a licensed electrician promptly.
Electrical systems should be quiet. When they are not, the sound is often the first clue that something is wearing out or loosening.
Sounds that are usually normal
- A low hum from a doorbell transformer, low-voltage lighting transformer, or some LED drivers
- A slight hum from dimmer switches, especially with incompatible bulbs
- A brief click from a relay, timer, or smart switch
Sounds that need attention
- Buzzing from the panel. Can indicate a loose connection, a breaker that is failing, or an overloaded circuit.
- Crackling or sizzling. Can indicate arcing, which produces intense heat.
- Buzzing from an outlet or standard switch. Often a loose connection or worn device.
- Humming from the meter base. Can indicate a problem at the service connection.
Why you should not open the panel
The main lugs inside a panel stay energized even when the main breaker is off, and arcing faults can be violent. Do not remove the panel cover, and do not touch a panel that is hot, buzzing loudly, or showing scorch marks.
What to do
- If there is smoke, sparking, or a burning smell, leave the house and call 911.
- Otherwise, turn off the affected breaker if you can do so without touching damaged equipment.
- Note when the sound happens, such as when the AC starts or when a specific appliance runs.
- Call a licensed electrician to inspect and repair it.
Older and corroded panels are more likely to develop these problems. Coastal homes see corrosion inside panels and meter bases more often. If your panel is aging, read our panel upgrade guide.
Frequently asked questions
Is it normal for an electrical panel to buzz?
A very faint hum can occur under heavy load, but noticeable buzzing, crackling, or sizzling is not normal and should be inspected promptly.
Why does my light switch buzz?
Dimmers can buzz with incompatible LED bulbs. A standard switch that buzzes may have a loose connection or be failing and should be replaced by an electrician.
Can a buzzing breaker cause a fire?
A buzzing breaker can indicate a loose connection or failing breaker that generates heat. Have it inspected rather than waiting for it to fail.
What should I tell the electrician?
Where the sound is coming from, when it happens, whether any breakers trip, and whether you notice heat or a smell.
Copperhead Electrical provides residential electrical service across Charleston, Mount Pleasant, West Ashley, James Island, Johns Island, Daniel Island, North Charleston, and Summerville. Call 854-444-6516 or request service online.