Ring mains and light fitting!

[DavidB66]

Help please! I bought a new light fitting thinking how hard can it be to fit it …. nothing in my house is simple as there are 5 wires in the ceiling rose! The blue (neutral) wire of the current light fitting appears to come off a black wire. The brown (live) wire appears to come out of another black wire. The green / yellow (earth) is attached to the fitting. There are two more red wires - they appear to go into a connector between the two blacks and separated from each of them with plastic.

The new light fitting only has a live and a neutral and an earth fitting. I am not sure if the two blacks are the live and neutral and go in those two holes? The earth seems fairly obvious. The two reds - an extra connector (4th part of the block) is provided with the light- do these go into that? Is this something to do with the ring? Advice very gratefully received!

 

[ericmark]

The British lighting system uses a sealing rose as a junction box between lamps this reduces the cable used between start and last lamp which is good as it also reduces the loop impedance.

So there are four connections.

Earth - Normally a clamp.
Line - Normally centre of rose with three connections.
Neutral - Normally one side of centre with three connections.
Switched Line - Normally one side of centre with two connections.

The Line only connects to lamp when using an emergency fitting which will auto light with a power failure and has batteries in (another reason for using this system) with all other lamps it just connects the supply to switch and next lamp in line but no direct connection to the lamp at that rose.

There are two ways to connect when not using a standard rose. One is use a small junction box and push it into the space between ceiling and floor boards and the other is to swap the three block connector strip for a four block one.

 

[DavidB66]

Thank you ericmark …. makes sense. Will give it a go now - always worry with electrics!