wiring a double light switch

[sarate2009]

we are trying to change an old metal double light switch for a new plastic one one we have an mk plug with 2 black boxes inside and each one has 3 thingummy bobs marked L1, COM and L2
we have two black wires and two red wires and one green ahd yellow
we have tried the two red in the two L!'s and the blacks the L2's and vice versa and nothing happened.
we dont know what to do with the earth either
any help wold be appreciated I keep falling over the dog in the dark

 

[Chri5]

Make sure you separate the two cables, each have a pair of red /black.

The earth should be terminated on the metal back box, their should be a grub screw in the corner. If the new switch has a earth point it's nice to run a bit of earth cable between the back box earth and the switch earth. Earth is sleeved in green yellow.

//www.diynot.com/wiki/_detail/...jpg?id=electrics:lighting:single_way_lighting

 

[sarate2009]

thanks I looked at the diagram but I am still not clear which holes to put which wires in...are you saying that the red should go into the COM hole and it doesnt matter which the black ones go in?

 

[PrenticeBoyofDerry]

It is possibly there are two earth cables in the same sleeve one for each set of cables.
You say that it's a double gang switch you are replacing, you have two reds and two blacks are this cables within a grey plastic sheath, might just be entering the back box by 5 of 10mm.
The cables ideally need to be in pairs each pair from each set of cables(grey sheath)
The red goes to Com and the black(this cable should have been marked up with red sleeve/tag) goes to L1 of each pair on the desired side of the switch.
Check the markings on the switch relate to the same gang, as they can be confused.

two gang switch

• PrenticeBoyofDerry
• 14 Jun 2012
• 1

It could be very useful if you had a multimeter available to you, to check for continuity and voltage!

 

[sarate2009]

Thanks its much clearer now but its too late and too dark so we are going to give it a go in the morning I'll let you know how it goes!