Earthing wires? - urgent

[postbox]

Can someone help me?
I am replacing a plastic switch with a metal one and there are only 2 wires which are red and black. There doesn't seem to be an earth wire. It is an old house and I wondered if that was the reason. If so should there be one and how do I put one in?
Also, another switch has an earth wire connected to the metal casing in the wall. Should I then be using further wire to connect from there to the metal switch?
Help - very confused!

 

[andy]

Can someone help me?
I am replacing a plastic switch with a metal one and there are only 2 wires which are red and black. There doesn't seem to be an earth wire. It is an old house and I wondered if that was the reason. If so should there be one and how do I put one in?
Also, another switch has an earth wire connected to the metal casing in the wall. Should I then be using further wire to connect from there to the metal switch?
Help - very confused!

you cannot use the new swicth without an earth. doin so is puttin your and any other persons life at risk.

unless you can find an earth... sometimes they get cut back, so there might actually be 1 there. if there is 1, make sure it is connected and workin.

in anycase, you should get a periodic inspection report done. might be time for a re-wire

 

[plugwash]

don't fit a metal switch unless you are reaonsbally sure the earthing is sound. If you find earth wires missing at some locations its quite likely that other earth wires may not actually be connected to anything.

another possibility is you have an installation where metal conduit is used as the earth. this is acceptable but only if the conduit is installed well and in good condition.

 

[ban-all-sheds]

another possibility is you have an installation where metal conduit is used as the earth. this is acceptable but only if the conduit is installed well and in good condition.

Difficult for a DIYer to test....

There doesn't seem to be an earth wire. ...how do I put one in?

Basically you can't - if this is the case then the lighting circuit needs rewiring.

And Andrew is right - if this is an old house, with old wiring, you should get the whole lot looked at..

 

[andy]

[ignore]