Humming noise from shaving point

[Mutley56]

Hi all,

Can you give me an idea ehy the electrical shaving point hums all the time that an electric toothbrush recharger is plugged into it. The shaving point is mounted on the side of a wooden cupboard. So, I was wondering whether the internal void of the cupboard was acting like an amplifier for what would otherwise be a much quieter humming sound.

The entire house was rewired last year by a competent electrician; Part P qualified.

Thank you for your advice.

Mutley56

 

[oharaf]

they do buzz as they contain a transformer. The cupboard may well amplify the sound!!!

 

[Mutley56]

Thanks for your opinion oharaf, I guess that'll be the answer then.

Mutley56

 

[Taylortwocities]

There's a thousand queries on this site re this problem. Try the search facility - its fun!

PS there's no such thing as a Part P qualification.

 

[Mutley56]

Thanks for your input Taylortwocities,

Will search the Forum, should've done that first. Got your point re: Part P, I meant that he was recognised by a competent persons scheme (NICEIC) for domestic electrical installations that fall under Part P of the Building Regs.

Thanks again.

Mutley56

 

[Mutley56]

As a follow up to my original post, the face plate of the shaver socket feels warm when the toothbruch recharger is plugged in.

The socket only hums when the toobrush recharger is plugged into it.

Is the heat normal, or is this a sign of problems occuring withing the unit? I can live with the hum, but not with the risk of an electrical fault causing a fire.

Thanks again for looking at this post.

Mutley56

 

[Steve]

All wirewound transformers hum and get warm. Its normal. Though IIRC, I dont think shaver sockets are designed for continuous use, so dont leave your toothbrush plugged in all the time.

 

[Mutley56]

Steve, thanks for reassuring me about the heat. I have stopped leaving the toothbrush recharger plugged in 24/7.

Thanks again.

Mutley56

 

[Steve]

As for the heat, do you have a laptop?

When you're charging its battery, clasp your hands around the power supply (black box mid-wire). You may well cry out in pain as they can be very hot.

As long as your shaver point is not this hot, no need to worry.

 

[Mutley56]

I'll have a go at the laptop recharger thing and see what it's like.

All the best.

Mutley56

 

[OilLecky]

Mutley,

I can confirm that what the others say is correct. A transformer is made up of thin layers of iron wrapped in copper wire. The layers of iron vibrate due to the magnetic field that alternates because the current passing through the copper wires is alternating. The copper wires get warm due to the effects of current flow, plus the iron gets warm due to circulating eddy currents. The two effects are known as "copper losses" and "iron losses". The lost power is dissipated as heat and sound. The amount of heat and sound depends on the load.