Some lights dim after removing ceiling rose Ask questions and find answers to many subjects relating to electrics and electrical work

[potnoodle23]

Would appreciate some feedback on this one, I'm sure it's a fairly basic mistake, but thought I'd ask anyway!

I installed a new light fitting, but unfortunately it was not large enough to house the existing ceiling rose inside it. I removed the ceiling rose and am sure I noted down correctly which wires went where, then did the following.

Joined the 3 red wires together using some terminal block, joined the 2 black wires together that were previously joined in the celing rose using terminal block and connected the neutral from the new fitting to this, joined the remaining black wire from the ceiling rose to the live from the new fitting using terminal block again. Twisted all earth cables together and connected those to the earth terminal of the new fitting.

When I turn the light on, it works a treat, but when it is off or on, other lights on the circuit appear very dim when turned on. Also, with the new light turned off, if I turn one or two of the lights on the circuit on, the new fitting lights up very dimly.

Any ideas? This sounds up your street Sparks from looking through the forums!

[potnoodle23]

I take it this is a tricky or a weird one!

You got any pointers sparx?

[333rocky333]

you have 3 blacks that is were you went wrong ,two go together neut in and neut out and one is on its own (switch return) live to fitting.

There is only three combinations

1 as above correct

2 willl short circuit blow fuse possibly blow switch this is where someone mistakenly joins the neut in, with the switch return,they then turn switch on and bang (quite embarrising)

3 Is what you have done ,you have joint the switch return with the neutral out,and wrongly used the neutral in as the live to your new fitting.
This puts the other fittings in series and the neutral return now goes through the new fitting lamps,creating about 120 volts across each fitting hence the dimness.
fortunately though this combinaton dont blow nothing
Locate the correct switch return and problem solved

[sparx]

Hi, just drawn out circuit and think you have wrong black as sw. wire putting your fitting in series with rest of lights, will need some sort of continuity tester to find wire back from sw. which I think you have as one of your Neutral pair, sorry not more help,
regards SPARX