I am fitting a new bathroom light fitting, and replacing the old connection block which has the existing wires connected to it, because the wire retaing screws are badley damaged. My problem is ,all the wires seperated and I now have 4 black wires 3 red and 2 earth wires. where do they go in the 3x3x2 screw block ? Help would be most welcome. Derek.

derek, February 2011

You have a problem.
1r and 1 b with 1e will probably be from the mains
a second set will possibly be out to other light units.
then 1R and 1B I would of thought would be to the switch. But that leaves you with 1 extra B. Do you have a timed fan in the bathroom? that could explain the extra. Basically, you need reds connected, then, the black from the switch, would go to one side of the new light, (THAT WOULD BE LIVE) when light is ON. the other side of new light would go to the other blacks. EXCEPT, FOR THE EXTRA BLACK.
BUT WHICH ONE? Unless you have test equipment, Get someone in.

Sheepdog, March 2011