I have bought a new bathroom light and taking the old fitting off have found 3 red wires bunched together and 3 black going to the terminal box of the old ceiling rose.
The new light wiring diagram does not show this combination should I call a sparky?!
We have a new RCD fuse box so if I did it wrong it would only trip out switch.

Firekay, October 2009

The 3 red wires are permanently live - leave these alone. There will be a single red wire which will come from the switch. your live (Brown) cable connects into the connector block with this cable. Your blue cable will connect to the black (Neutral) cables. If you are not sure get a spark. Good luck!!

Tony McD, October 2009

One of the cables could be a switch wire, so the black of it would go to the live on the fitting with the other reds together in the loop terminal.

Adam, October 2009

call a spark, bathrooms are special locations and come under part p building regs, intentionally tripping out circuit protection is not a good idea, ie if you have a high prospective fault current, you could damage the mcb, wiring, scare the dog etc

sparkiefc, October 2009