Buzzing at MCB

[gasman]

I have just fitted 7no low voltage 50 watt lights in my lounge ceiling. They are controlled by a dimmer switch. When the lights are on fully, no noise from the MCB, when i dim them there is a buzzing noise at the MCB that the lights are on.

I have double checked all connections and swapped dimmer with different one. The dimmers i have used are of the correct rating for the load that is drawn.

Any ideas would be appreciated

 

[Steve]

And the dimmer and transformer are compatible?

 

[gasman]

In what way do you mean.

 

[kevindgas]

lights are not suitable for use with a Dimmer i would suspect. usually the dimmer buzzes

 

[gasman]

Yes the dimmer does buzz. I have tried different dimmers and the noise is still there.

 

[gasman]

Could it be dangerous or just an annoying buzz.

 

[kevindgas]

Could it be dangerous or just an annoying buzz.

yes it is dangerous. find a suitable light or don't fit a dimmer. and soon before you set alight the fittings and possibly your house.

 

[Steve]

not nessecarily dangerous, but check the dimmer is able to dim a transformer, and check that the transformer is able to be dimmed!

 

[Adam_151]

not nessecarily dangerous, but check the dimmer is able to dim a transformer, and check that the transformer is able to be dimmed!

....and that the connections to the MCB are sound.

If it is still there, try replacing the MCB (swap with upstrairs breaker), if that doesn't cure it then if the Zs are ok to do so then could try a C curve one

 

[GaryMo]

If it is still there, try replacing the MCB (swap with upstrairs breaker), if that doesn't cure it then if the Zs are ok to do so then could try a C curve one

Why a C type? If inrush was a problem then the existing B type MCB would surely trip on start-up?

 

[Adam_151]

I knew someone would ask

Shorter coil for the magnetic trip part of the breaker, should reduce the amount of 'transformer hum' it suffers from, but I'd swap it for an indentical one first, it could be that the first one is poorly made

 

[GaryMo]

I knew someone would ask

Shorter coil for the magnetic trip part of the breaker, should reduce the amount of 'transformer hum' it suffers from, but I'd swap it for an indentical one first, it could be that the first one is poorly made

Always good to have a reply ready then

Thanks for the explanation though, didn't know that.

 

[gasman]

Thanks for all the advice from everyone.

I have swapped mcb's and the noise is still there. I will probably fit a normal switch.

 

[Adam_151]

Thanks for the explanation though, didn't know that.

I can't take much credit, its cropped up somewhere else before and the explanation given just made sense (and I was supprised I'd not looked at it that way before)

Anyway a 5A BS1361 would totally eliminate buzzing MCB syndrome even better than anykind of breaker