Dimmer switch installation confusion

[Justin41]

Hi,

Sorry if this has been covered before but i'm a bit stuck.

In the living room we have a standard plastic single light switch (has a metal cage sunk into the wall) and wish to swap it for a metal dimmer switch which I brought today. When I took the screws out of the old plastic switch I was faced with 2 black wires and a green stripy wire which was taped up and just tucked at the back (earth wire I presume?). The 2 black wires are connected to L1 and L2 on the old socket.

On the new metal dimmer switch it has L1 and L2 and a wavy symbol and also a earth connector on the back where the screw goes through to connect it to the wall.

I know that the taped up green stripy wire will connect to the earth on the dimmer but im not sure what to do with the L1 and L2? I have marked the black wire That goes into L2 on the old switch so I know which is which

Can anybody help?

Thanks

 

[AndyPRK]

I guess one black wire into the wavey terminal.

Other black into one of L. 1?

 

[SimonH2]

Look at the instruction for the dimmer - it'll have a diagram of where to connect the two wires for a basic circuit. Whatever two terminals it shows being used - put your two black wires into those terminals.
The green stripy wire "should" be an earth, but there's no guarantee. You will need to test if this is an earth - because if it isn't, then it is NOT safe to fit the metal dimmer switch. Provided it is an earth, then it goes into the earth terminal.