You open the closet or garage and hear the electrical panel. Is that normal? A faint, steady hum can be. Loud buzzing, crackling, popping or sizzling is not. The panel is where every circuit in the house is connected, so a sound coming from it deserves a careful look. This guide covers the panel specifically. For sounds from an outlet or switch, see our guide to burning smells and buzzing from outlets.
If you smell burning or see smoke
Do not open the panel. Get everyone out, and call 911. If you can do it without touching a hot or sparking panel, and it is safe to reach, a main disconnect outside at the meter can be switched off. Otherwise leave it for the fire department.
Sounds that can be normal
- A faint, steady hum that you only hear with your ear close to the panel, especially when a large load such as the air conditioner is running.
- A single click when a breaker trips or you switch one.
- A hum from the meter or FPL's equipment outside rather than the panel. Transformers and some meters hum by design.
Sounds that are a warning
- Loud buzzing you can hear from across the room.
- Crackling, sizzling or popping. That is the sound of current arcing across a gap: a loose connection, a damaged breaker or a breaker that is not seated on the bus.
- Buzzing that gets louder when a particular appliance runs.
- Buzzing with heat: a warm panel cover or a breaker that is hot to the touch.
- Buzzing with flicker elsewhere in the house.
Common causes
- A loose wire on a breaker. The screw holding the wire has loosened over time, and current is jumping a small gap.
- A breaker that is not making good contact with the bus bar it clips onto. This is a known weakness in some older panels; our guide to Zinsco and Sylvania-Zinsco panels explains one example.
- An overloaded breaker carrying close to or over its rating.
- A failing breaker that hums before it fails to trip or trips repeatedly.
- Corrosion and moisture. In garages and on exterior walls near the coast, rust on the bus, lugs and breakers makes poor connections. See salt air corrosion.
- Loose main lugs where the service wires connect. Often accompanied by flickering or lights that get brighter and dimmer; see the lost-neutral warning.
What to do now
- Keep the cover on. Do not remove the panel cover. The main lugs inside stay energized even with the main breaker off.
- Find the source if you safely can. With the panel door (not the cover) open, switch off the larger loads one by one: the air conditioner, water heater, dryer. If the sound stops with one, note which.
- Switch that breaker off and leave it off if switching it off stopped the sound.
- Feel the cover with the back of your hand. If it is warm, or you smell anything, call promptly.
- Take a photo of the panel with the door open and the label inside the door.
What we check
We remove the cover with the right precautions, use a thermal check and a meter to find hot or loose connections, and inspect every breaker, the bus and the lugs for heat damage, arcing marks and corrosion. Often the repair is remaking one connection and replacing one breaker. If the bus is damaged, the panel is a type with known problems, or there is widespread corrosion, we will explain the options. Our electrical panel repair page covers repair or replace, and nine signs a panel needs replacing lists the signs that point to replacement.
Questions people ask
Is a humming panel going to catch fire?
A faint hum is usually not dangerous. Crackling, sizzling, heat or a smell can be, because they point to arcing at a connection. Treat those as urgent.
Can I tighten the screws myself?
No. Working inside a live panel is dangerous even for people who do it every day, and a connection that has been arcing usually needs the wire and breaker replaced, not just tightened.
The buzzing stopped. Do I still need someone?
Yes, if it was loud, crackling or came with heat. An arcing connection can go quiet and come back.
Why panels in garages and on exterior walls need more attention
Many Miami homes have the panel in the garage or on an outside wall. Those panels see more heat, humidity and, near the coast, salt air than a panel in an interior closet. Over the years that shows up as rust on the bus and breakers, and as connections that loosen as metal expands and contracts. A panel that has started to buzz in one of these locations is worth a full inspection, not only a fix to the breaker that is making noise, because the conditions that loosened one connection usually affect the others.
Do panels make more noise as they age?
Not by design. A healthy panel of any age should be close to silent. A panel that has become noisy over time is telling you something has changed.
Need it looked at?
KRW Electric (EC13012832) troubleshoots and repairs buzzing and crackling electrical panels in Pinecrest, Coconut Grove, South Miami and Miami Beach, with same-day service when scheduling permits. Call (305) 359-7312 and tell us what you are seeing. We will ask a few questions, tell you whether it sounds urgent, and give you the earliest time we have. Our before you call checklist covers what to have ready, and what happens on a repair visit explains the rest.
Reviewed by Kyle White, KRW Electric Company LLC — licensed electrical contractor EC13012832.
