Buzzing Light switch

[slawit]

Hi All

I have just changed a plastic light switch for a new decorative metal one. If I just touch the switch without moving my finger I don't feel anything, but if I run my finger across the face of the switch it feels like it is "buzzing", there is no pain or electric shock and I have touched it more than once but I don't want to presume it is safe until I know what is going on. Any ideas what is going on? There is no earth wire to the switch

Regards
Slawit

 

[jj4091]

Hi Al There is no earth wire to the switch

Regards
Slawit

There should be. You should not fit metal face plate accessories without adequate earthing. I'm not saying that is what is causing the "buzzing" but what you have done is potentially dangerous.

 

[bernardgreen]

As mentioned you have created a potential dangerous situation. You must replace the metal switch with a plastic one.

The "buzz" you are feeling is 230 volts capacitively coupled from the wires to the metal plate. Because the capacitive coupling is very small the current through you is limited to a very small and harmless current.

If a fault happens and a live wire comes into contact with the metal plate then the current is not limited and, depending on what else you are touching will give you a severe and possibly fatal shock.

A not un-common fault is a wire trapped between the back box and the front plate when the switch is fitted. Eventually the squashed insulation gives way and the live wire makes contact with the back box and in your case the metal front plate.

 

[bernardgreen]

If there is no earth to the back box then when you refit the plastic switch you should consider using nylon screws to fit the switch to the back box or use a switch that can take plastic covers over the screws.

This will prevent anyone getting a shock if they touch the screw head should a fault ( squashed or loose wire ) have made the back box live.

 

[JohnW2]

I have just changed a plastic light switch for a new decorative metal one.

What others have said about the earthing is correct. An unearthed metal switch plate is potentially dangerous, and must not be left like that. The instructions which came with the new switch should have told you that.

Is this just an ordinary switch or a dimmer?

Kind Regards, John