I recently begin noticing a loud humming noise coming from my circuit breaker panel in my basement when I use a 1500 watt space heater on high in my living room in addition to the other electronics using a minimal amount of power. While I hear the loud humming, the circuit does not trip not matter how long I leave the heater running. When the heater is off the humming stops.

I was wondering is this a sign of a circuit not tripping when it should? Is it a fire hazard or does it pose a risk of damaging any electrical components? If I do need to replace a circuit, is that something I could do just by shutting off the main circuit to the house, testing with a voltage tester pen and replace it myself?

Thank you.

  • What brand of panel do you have? Some panels have problems that cause arcing zinsco and federal Pacific are 2 that have have problems and may need a professional evaluation. If a modern square D, Siemens, cutter hammer, GE, the breaker may be going bad, breakers are cheap, make sure to get the same amperage and model when replacing. – Ed Beal Feb 2 '18 at 18:52

If you're getting noise, either the breaker is failing or the wiring is getting loose and so can vibrate. It might be a simple as tightening the connection that holds the wire into the circuit breaker. If this doesn't fix it then you can try replacing the breaker.

Don't play with your main panel unless you know what you're doing! :)

BTW, the circuit breaker should not trip unless there is too much current going through it. Are you in the USA? If so, your power is 120VAC. The two standard breaker ratings are 15A and 20A, which should handle 1800W and 2400W, respectively.

So unless you have other significant loads on the same circuit I would not expect the breaker to trip.


I suspect the the heater is on a circuit that doesn't really have the capacity to handle 1500-watt load on a single appliance. A 1500-wall heater should be on a dedicated 20-Amp circuit with 12-guage wire and a spec grade receptacle. If you do this it will not only fix this problem but make your overall house safer at the same time.

  • Almost all of my circuits are 15 amp circuits. Would it be worth upgrading the whole circuit to a 20 amp circuit? – Justin Todd Feb 2 '18 at 19:32
  • 1
    A 15 amp circuit is fine to run a 1500w heater that is only 12.5 amps this is the reason most space heaters max out at 1500w because that is 80%. There is a safety factor built into residential wiring in fact the 90 degree table for 14 gauge wire allows 25 amps NMB wire or brand name romex is listed for 90 deg but code limits its ampacity to 15 amps, inside equipment enclosures 14 gauge max is 100 amps outside the enclosure it is limited to 45 amps NEC table 430.72.B. so there is no reason to rewire your home just replace the breaker. – Ed Beal Feb 2 '18 at 20:22
  • With a 20 amp??? – Jack Feb 2 '18 at 21:05
  • You can't upgrade an existing 15-Amp circuit to 20-Amps without up-sizing the wire to #12. – Paul Logan Feb 3 '18 at 7:00

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