Dimmer switches work by chopping up the AC current flowing between the switch and the light. ... The interrupted current can produce a vibration in the electromagnetic field within the light bulb filament or within the switch itself, which can cause a humming or buzzing noise.

Should a dimmer switch buzz?

Dimmer switches do make a slight buzzing sound due to the interruptions to the electromagnetic field that naturally exists around a live wire. A buzzing sound from the switch is usually not dangerous, unless accompanied by a hot switch or a crackling noise.

How do you stop a dimmer from buzzing?

Upgrading Your Dimmer Switch

If you're wondering why your dimmer switch is still buzzing, it may be that it is rated too low for the task, and is being overtaxed by the combined bulb wattage. Try taking a few bulbs out of the switch circuit and see if it reduces the buzzing.