Metal 2 Gang light switch not earthing correctly?

[akbmcf1]

Hi everyone,

First off, please don't shout at me, as all I have done is replace a switch and I believe I have done everything correctly!

In my kitchen I have some downlighters on one circuit, and a main light on another, both originally wired into a metal 2 gang dimmer switch. At times, when switching the lights, you could get a slight buzzing feeling off the casing, and sometimes a slight nip when switching the light so I presumed it hadn't been earthed correctly. One of the dimmers went, and I don't like dimmer switches anyway, so I have replaced with a metal 2 gang 2 way toggle switch.

I've wired both switch cables as follows: Red to common, black to L1, and earth to the earth terminal on the pattress. I've run an earthing cable from the terminal on the switch plate to the earth terminal on the pattress. Both switch cables are twin and earth and are both also earthed onto the pattress.

However, now I've put the lighting circuit fuse back in, there is still a slight buzzing feeling if you touch the casing, and just occasionally, you get a slight nip when switching the lights on or off. The lights work fine however!!!

Is there anything I'm missing?

Thanks in advance for your help.

 

[Taylortwocities]

Although you have connected a wire that appears to be the earth wire I would bet that it isnt actually connected to earth.

you are getting induced voltages fed back down that wire onto the case. Thats why there's a pulse when u switch off. You need to trace the wire and get the earth sorted or get someone who knows what to do to sort it.

I will bet that whoever put your downlighters in didnt connect all of the earths through and it is missing at the point where the switch wire connects to the feed wire. Assuming that your lighting circuits have an earth in the first place..??

 

[RF Lighting]

I suspect that your earth wire in the switch isn't actually connected to earth at the other end. This will cause the switch plate to become 'live' due to a small bit of electricity being induced onto the floating earth wire.


Bah too slow!!

 

[fireman22]

check the lights these switches are feeding maybe you have a live or neutral going to earth. also is the earth sound, with a tester this may be hard to prove for you. see if you can identify which light or set of lights is giving the tingle sensation

 

[fireman22]

god you two are quick

 

[Taylortwocities]

We dont have a life, fireman, and we dont have those annoying sirens and bells going all the time

 

[akbmcf1]

Hey guys, thanks ever so much for your help.

My plan of action is as follows:

Disconnect both earth wires, and then reconnect one at a time to ascertain which set of lights is causing the problem.

If it is the downlighters, what would you recommend next? Not earthing the switch cable, or should I be able to tell which of the lights is not connected properly by taking the downlighters out and checking the wiring?

Thanks in advance again. (If I'm asking "how long is a piece of string?", feel free to tell me!!)

 

[bernardgreen]

Until the problems with the missing earth is rectified replace the metal switchs with plastic ones.

 

[akbmcf1]

And (i'm guessing) don't touch the screws holding the switch plate on??

 

[bernardgreen]

And (i'm guessing) don't touch the screws holding the switch plate on??

Correct

You can get plastic screws, but don't tighten too tight, or a face plate with recessed screws and a press in plastic cap to cover the screws

 

[akbmcf1]

Any pointers on where to start tracing the wrongly connected or not-at-all connected earth cable?

 

[Taylortwocities]

Hint, again...

I will bet that whoever put your downlighters in didnt connect all of the earths through and it is missing at the point where the switch wire connects to the feed wire. Assuming that your lighting circuits have an earth in the first place..??

 

[akbmcf1]

Hey guys, had a thought about this problem when at work today - see, I'm learning!!

You said in your replies about induced voltage, perhaps from an earth on the switch cable not being connected and therefore pinking up voltage from its proximity to other cables carrying power.

Anyway, I came home, found one of those voltage tester screwdriver things with the bulb in the handle and set to with my investigating.

The 2 gang 2 way switch that I originally posted about is mounted right next to a 1 gang switch that runs the under-cupboard lighting in the kitchen, so you have 3 switch cables running down the wall for starters. Then I realised that on the other side of the wall, there is another 2 gang switch in the hallway that runs the hall lights and the landing light, which is another 2 switch cables running down the wall!

I set to with my voltage tester screwdriver, and found that I am getting voltage showing through the faceplate screws of all 3 switchplates. So I am thinking that the induced voltage problem is probably because of a high concentration of switch cables in a small area (what leads me to this conclusion is that I can even feel a slight "buzzing" feeling if I lay my hand on the wall above the switch in the hallway which I presume is me picking up induced voltage that is running to ground through me!!)

Whaddya think? Have I cracked it? Am I going to have to swap all the metal switches to plastic ones?

 

[RF Lighting]

All that shows is that all 3 switches are probably not earthed (although they may all have their earth wires connected together)

 

[Taylortwocities]

Sort out the earthing and you'll probably be OK.

Dont trust those neon screwdrivers. Put it in the bin