Changing an old dimmer switch for a new 1. Earth required? Ask questions and find answers to many subjects relating to electrics and electrical work

[tinks]

Hi, trying to change an old dimmer switch for my bedroom light. The button is missing so I bought a 1-way white plastic fitting.

When I tried to replace the old one it was different inside. It had 3 wires going into it (black, blue and earth). My new one only had places to fit 2 wires and in the instructions it says to connect the earth to the box fitting or something. There doesn't seem to be anywhere on the box to fit the earth though.

What do I need to do?

[sparx]

Hi Tinks, the earth just goes to a small connector in the back of the box, unless using metal sw. which u r not.
Prob is your wiring colours don't add up, blk & blu???any way 2 wires, 2 terms. no prob! either way round will work, presume old sw. was metal so 3rd term was on back plate for earth wire?
regards SPARX

[tinks]

Thankyou for your swift reply. Much appreciated.

I prob got the colours mixed up. Will have another look tonight but I couldn't find anything to connect the green & yellow earth wire to last night. *The metal box that is set into the wall was already there, I am just trying to replace the front plate with the actual button on. The old front plate which i removed is metal and on the back of it all 3 wires were connected to terminals on it.

The new front bit iv bought is plastic and only has 2 terminals. So I should find a place to connect the earth to somewhere in the metal box that is in the wall?