transformer hum

[normaninuk]

I have installed new low voltage lights in lounge.12v halogen bulbs.The problem is that when the light is switched off at the wall the fitting emits a loud hum from the built in transformer.When you switch it on the hum is reduced considerably.The power is supplied at the ceiling by the 3 wire system where the lives are looped through to the next room.

 

[Taylortwocities]

If the switch is off, there should be no voltage at the transformer terminals so it should not 'hum'.

Do you have a multimeter? Need you to measure across the live and neutral terminals to the light fitting with the switch off. Tell me how many volts AC that you see.

Cheapo lights can hum when they are switched on, especially if there is a dimmer involved. Do you have a dimmer on this light?

 

[normaninuk]

There is no dimmer switch controlling the light.I have disconnected the light at the moment and will need to check if there is a voltage when off at the wall.When the light is switched on it still hums but a lot quieter

 

[JohnW2]

I have installed new low voltage lights in lounge.12v halogen bulbs.The problem is that when the light is switched off at the wall the fitting emits a loud hum from the built in transformer.

It sounds almost as if you have the switch switching the (12V) output of the transformer, rather than the mains going into the transformer. Do I take it that you are sure it's wired correctly?

Kind Regards, John.

 

[normaninuk]

The light is a ceiling mounted 8 bulb halogen fitting and the switch is the normal light switch on the wall.I have wired the light fitting with the fitted cables.Earth to earth.Neutral to the two neutrals and the live to the cable returning from the switch .The other three cables looped together are the two looped lives and the switch live as per normal