Why does electricity buzz

Even though you might see a coil consisting of varnished wire that is glued down or epoxied really tight, the magnetic force is still tugging on these wires ever so slightly to great vibration. It doesn't have to be the coil wire itself either, it could be any metal object around the coil. The force is there and it's pushing and pulling on that metal back and forth at times a second.

For high-voltage lines outside on poles, it's a different story. That is, if you aren't around any transformers like you see in those big distribution plots.

What you are hearing is not corona discharge as that is mostly silent unless when you get total breakdown you will hear and see arcing. After rain, or when moisture levels in the air raise you get condensation developing on the ceramic insulators that hold up the cables. You will notice these are shaped oddly like little half-domes so as to make it harder for a stream of water to make a connection between the live line and ground or another phase.

They aren't perfect though, and when rain or moisture develops on them, it can create shorter little paths for the current to travel. What you are hearing is tiny little bursts of water boiling off the insulators.

The reason for this is something known as "magnetostriction", which is strain induced in a magnetic lattice due to the magnetic nature of a material. There is a pretty good explanation of the buzzing noises in transformers in the article Magnetostriction aka: Why Transformers Hum , but the summary is that the ferromagnetic domains in the transformer core are subjected to the 60Hz in the US oscillations of the magnetic field due to the AC current. Because of the electrical cycle, there are two impacts on the core per AC oscillation, so the strain is changing at 60 Hz, which produces the Hz noise that we can identify a "great B" note.

Well, it's only a Wikipedia reference, but it says for high voltage power lines, it can be corona discharge. For transformers or other objects containing coils, it can be magnetic. Seems to me, for things carrying AC, it's pretty hard to make them not hum.

Nearly everyone here has posited magnetostriction as the cause for the hum. This is most certainly the case for transformers which have large amounts of ferrous material put in laminated sheets to form the core, but is a doubtful explanation in the case of power lines. Power lines don't have nearly enough magnetic material to produce large enough deformation to give rise to a loud hum that a passer-by may notice. The more likely cause, especially that it is mentioned the hum is noticed particularly after the passage of a train, is the vortex-shedding.

Wind flow over the wire at a sufficiently high velocity, generates a series of vortices that are periodically shed forming the so-called von-Karman vortex street in the aft of the bluff body. Now this phenomenon maintains fantastic periodicity for a reasonable range of Reynolds numbers.

This aeolian effect is called Conductor gallop for low frequencies and flutter for high frequencies, which corresponds to the "singing" of power lines. As you can infer from the answers here, there are at least two correct and different answers. A magnetic field exists around an object carrying current. This field interacts with the earth's magnetic field to exert a force than acts on the current carrying wire.

There is some movement of the wire caused by the magnetic field surrounding it. High tension wires are Aluminum clad Steel I used to work at a 50Kw AM radio station that had a large audio transformer in the transmitter the transmitter was "plate modulated". The transformer acted as a Lo-Fi speaker due the transformer winding movement at audio frequencies the modulating signal. In the same way, motor windings will make a 60 Hz, plus many harmonics multiples of sound when powered with a cheap square wave inverter.

This is because the square wave contains high harmonic energy multiples of 60Hz. Loose windings, more noise. The second way power lines hum is electrostatic, related more to voltage than current as the magnetic effects described above are. The lines become an "electrostatic speaker" based of an electric, instead of magnetic field. The sound may be unnerving, but it typically does not pose a hazard to nearby people. Low, steady humming or buzzing in household appliances or devices is usually nothing to worry about.

If you notice sounds that are louder than usual, or hear crackling, sizzling, or other unusual noises, unplug the device immediately and have it inspected by a professional before further use. If your florescent lighting has recently started buzzing loudly or flickering, the light ballast may need to be replaced.

Pay special attention to your circuit breaker panel. In this case, trying to fix the problem yourself may be dangerous. Promptly call a professional to investigate the issue and fix the problem! Damaged electrical wires or components can cause electrocution or fire, and attempting to fix faulty appliances on your own may void your warranty. If you have any concerns regarding your electrical panels, wiring, or electrical devices, contact Mr.

Electric online or call to schedule an appointment. Noisy water pipes? Let the experts at Mr. More than 40, subscribers can't be wrong. In music, a note is governed by its pitch, which is based on the frequency of the sound. The higher the frequency, the higher the pitch. Generally speaking, a scale starts with A, which is Hz.

The next lower A is at Hz, then at 55 Hz, and so on. Since the electrical hum depends on the frequency of the current, so the sound will pretty much have the same frequency as the current.

In the US, the current frequency is 60 Hz tone. The rest of the world uses 50 Hz current frequency, which means that the note resulting from the electrical hum is closer to a G a bit sharp. Hums can also appear at the frequency harmonics, though with a much lower intensity.

So in the case of a 60Hz current, you could have some humming at Hz, Hz, and so on, up until very high frequencies.

Generally speaking, the hum is an annoyance, especially in musical instruments that involve electricity. At a venue, this electrical hum is often picked up via a ground loop.

An alternative way to fix this is the audio humbucker. Electric guitars especially and sometimes microphones use one or several humbuckers, which are basically two coils instead of one.