Power Outage ??????

[JoeLee]

The other day we had a power outage. As the lights flickered I heard a loud deep buzzing sound that reverberated in my breaker box.
I know there was nothing arcing in there as this happened last year. A transformer about three miles away shorted out and as it was spittin and sputtering it sounded like it was coming from inside my box, you could almost feel the vibration.
What is the reason that when a transformer blows you can hear it inside you breaker box?????
This is a strange phenomena.


JL............

[Paul Alciatore]

Breaker boxes are usually made of steel, which is magnetic. They frequently hum in normal operation. If that transformer had a partial short on the primary side, then the secondary, output Voltage to your building could have stepped up to a higher value. That higher value Voltage could have caused greater than normal magnetic fields inside your breaker box and that may have caused parts of it to vibrate. Did anything in your building burn up due to higher Voltages?

[darryl]

I suspect that anything that tries to knock the peaks off the sine wave, like a short, is going to leave more like a square wave on the line. This is much more audible through equipment than is a sine wave.

[Arcane]

The other day we had a power outage. As the lights flickered I heard a loud deep buzzing sound that reverberated in my breaker box.
I know there was nothing arcing in there as this happened last year. A transformer about three miles away shorted out and as it was spittin and sputtering it sounded like it was coming from inside my box, you could almost feel the vibration.
What is the reason that when a transformer blows you can hear it inside you breaker box?????
This is a strange phenomena.


JL............

If it was three miles away from you, how could you hear it "spittin and sputtering and hear a buzzing sound in your breaker box at the same time?

[J Tiers]

The usual circuit breaker is thermal. They tend not to make much noise, but could do.

Some of the main breakers are combined thermal and magnetic. The magnetic element surely can make noise if the current varies in it more than normal 60 Hz. The staccato pulsing of an arc somewhere that is cutting the power, could very well cause it to make noises.

[JoeLee]

Breaker boxes are usually made of steel, which is magnetic. They frequently hum in normal operation. If that transformer had a partial short on the primary side, then the secondary, output Voltage to your building could have stepped up to a higher value. That higher value Voltage could have caused greater than normal magnetic fields inside your breaker box and that may have caused parts of it to vibrate. Did anything in your building burn up due to higher Voltages?

No, nothing burned in my breaker box and no appliances were damaged in bot instances.

JL......................

[JoeLee]

If it was three miles away from you, how could you hear it "spittin and sputtering and hear a buzzing sound in your breaker box at the same time?

The spittin and sputtering sound was heard coming from the breaker box when this happened the other day.
The one that shorted last year was two streets over from me and it was loud and I saw smoke coming from it. As it was arcing away it sounded like it was coming from my breaker box. There is some connection between these transformers shorting and the noise resonating from inside the box.
Maybe darryl is on to something.

I know the normal humming that comes from high voltage / amperage boxes like in factories or big buildings, but I've never heard any sound coming from a residential box.

JL................

[Paul Alciatore]

Just to be on the safe side I would have a good electrician check out that box.

[PStechPaul]

A thermal-magnetic breaker will make sounds as it approached the trip point:

A shorted transformer near the breaker box may produce distorted waveforms with net DC offset that can make unusual sounds as the voltage may collapse and rebound as windings short and blow open and arc. High current surges in the HV primary line may cause the wire to jump and emit several "bong" sounds.

[justanengineer]

The only times I've ever heard something inside a residential breaker box there was either a major electrical issue or a rodent in the process of causing a major electrical issue.

[PStechPaul]

Sometimes there is a doorbell transformer attached to the box, and it can buzz loudly when overloaded or when laminations get loose.

[JoeLee]

No door bell buzzer. This isn't the normal arcing sound that you would hear when something shorts on house hold voltage.
This sound was the kind of arcing sound that you would hear if you were in a steel mill when the electric furnace arcs.
Very high voltage and high current sound.
You could almost feel the vibration from it.

No damage was done either time this happened as over 7000 houses were with out power.

JL..............

[J Tiers]

It's the effect of the magnetic field, you hear it because the arc makes a high frequency noise, but does it at line frequency,if that makes sense to you.... bursts of high frequency as the line voltage rises and falls at 60 Hz.

The box etc is a lousy "speaker" for lows like line frequency, but could work as a speaker for higher frequency noises. Your ear supplies the lows due to the noises varying at 60 Hz.

If the transformer supplied 7000 houses, it was a big one, likely 20 MVA (20,000 kVA) or better. Big arcs, you might have seen them light up the sky like the videos during the hurricane up in NYC. It sent out voltage pulses at high power to everyone at the same rate as the arcs, so I believe stuff was a-buzzing....

it basically sent out what amounts to an audio signal at very high power, that corresponded directly to the arcing etc. So no surprise it sounded like that through anything that would respond to it.