When it comes to home ownership, mysteries are rarely fun. Mysterious stain on the ceiling? Better check the toilet upstairs. Mysterious odor in the kitchen? Check the garbage disposal or the potato bin. (It’s almost always a forgotten Russett in the far back corner of the pantry.) Mysterious humming or buzzing noise? Better check the… ummm… where in the world is that coming from?
Most people have trouble tracking down a low-frequency hum or buzz, and if you’re a person of a certain age (ahem), it may be especially tricky trying to figure out if it’s coming from somewhere in the house… or if the Summer of Rock is finally catching up with you. As frustrating as it is, it’s worth hunting down and addressing the sound.
Possible Causes of Electrical Hums and Electrical Buzzes
Rather than torture you with a science lecture, here’s the simple explanation: Sometimes powered appliances or electronics vibrate a bit, and that vibration produces a completely normal type of electrical sound called mains hum.
You’ve probably heard mains hum when your fridge cycles on or when you’ve walked under high-voltage power lines or near electrical transformers. Fun fact: In the United States, our standard power is 60 hertz, and mains hum sounds like a B-flat. But in Europe, power is 50 hertz, so mains hum sounds more like a G.
While mains hum can be annoying, it’s not dangerous. However, every other cause of humming or buzzing is potentially problematic:
- Mains buzz. If you notice your mains hum transition to more of a loud buzzing, you should contact an electrician right away.
- Outlets or switches. Three issues can create humming or buzzing from an outlet or switch: a loose wire, an overloaded wire, or an improperly grounded wire. Each of these situations is a fire hazard, so you’ll need to involve a professional electrician.
- Light fixtures. More often than not, a humming or buzzing light fixture simply needs a new bulb. This is particularly true of lights operating on dimmer switches, and you’ll save yourself some frustration by choosing bulbs specifically designed for dimmers. If the noise persists after you swap out the bulb, call in a pro.
- Circuit breaker. If you trace your hum or buzz to your circuit breaker, immediately switch all circuits to off, and schedule a service call right away. When circuits get overloaded and can’t turn off, they make noise, and so do damaged and loose wires. Humming or buzzing at the circuit breaker can also signal the formation of an electrical arc—which is every bit as dangerous as it sounds. Only a licensed electrician should be messing around inside your circuit breaker.
Tracking Down Electrical Hums and Buzzes
Sometimes humming or buzzing comes from an obvious spot, but most of the time it doesn’t. To determine the source of your sound:
- Turn off all your circuit breakers.
- Walk through your home and see if you can still hear the hum or buzz. If yes, your problem isn’t coming from your electrical system or appliances. If no, proceed to step three.
- Turn on each circuit, one by one, and then walk through your home to see if the noise has returned yet. When you find the circuit on which the buzz or hum lives, investigate everything powered by that circuit—appliances, switches, outlets, and fixtures—until you’ve located the problematic element.
If you’re convinced your problem is on a particular circuit but you can’t pinpoint the exact location of the hum or buzz, hold a funnel to your ear (large side out) to amplify the sound. You can also try using a high-quality microphone and headphones. If you think your electrical sound might be inside a wall, get your hands on a stethoscope and see if you can root it out that way.