does changing one ceiling light effect the rest? PART 2?

The extractor will need its own live and neutral and a connection to Switched Live as a signal to begin extracting.

Peccavi
April 2009

http://www.flameport.com/electric/lighting_circuits/lighting_ceiling_rose_other_colours.cs4

Each ceiling fitting requires 3 terminals plus the Earth of course.

Live / Neutral / Switched Live / Earth

All the Live wires (Red or Brown) connect together and to nothing else (The Loop) - In, Out & off to the switch.

The return from the Switch, Black with a sleeve (or possibly Blue if you have the new Euro colours) connects to the Live wire for the lamp - just these two together and to nothing else.

The remaining neutrals and the neutral wire for the lamp all connect together.

Good Luck...

Peccavi
April 2009

Yes it does - by connecting all of the live wires you will cause the wall switch not to work and your bathroom light will be constantly on. If you disconnect one of the lives then the loop won't continue to the other lights - or you wont be able to turn the bathroom light on at all. As you are finding - identifying which live wire is which is an absolute nightmare...and its why a 'proper' sparky will mark the switch wires with tiny pieces of insulating tape, or in fact use cable with 'twin reds' that is, indicating that both will be live when the switch is on. The proper way to fit a different light fitting is to move the loop in rose into the loft, and just suppy the new fitting with a neutral, live and earth from there. Sorry I can't be clearer, but if you check out the DIYnot forum, you'll find diagrams in the electrics UK section. Best wishes!

John
April 2009