What this usually means
A faint hum from a panel can be normal transformer or breaker noise. A loud buzz, a crackle, a sizzle, heat, or any burning smell is not, and means the panel should be evaluated before it is used further. Do not open the panel cover to investigate.
The common causes
An electrician works through 4 conditions that all produce is my electrical panel buzzing or humming. They are listed so you can describe what you are seeing accurately — not so you can decide which one applies, because several of them look identical from outside the equipment.
- Loose connection arcing — Arcing at a breaker, bus or termination, which produces both noise and heat.
- Failing breaker — A breaker that is deteriorating internally can buzz under load.
- Overloaded circuit — Sustained heavy load producing audible noise and heat.
- Normal equipment hum — Some transformers and devices hum quietly in normal operation.
What to note before you call
For this symptom specifically, 4 observations do most of the work. Note them from a safe distance and do not open anything to check. Having them ready turns a vague call into a productive one and shortens the diagnostic visit.
- Whether the noise is constant or load-dependent
- Any heat felt through the cover, or discolouration
- Any burning smell
- Whether breakers have been tripping
What happens next
An electrician tests the circuit, isolates the cause and explains what the repair involves before doing it. Where this points at urgent electrical help, that page covers what the work usually includes and what changes the scope.