Dimmer Dilemma

[Heather]

I bought a new ceiling light fixture and a single dimmer switch t

replace the existing fixture and single switch. I installed the dimme switch first which worked with the existing light fixture, no problem on, off, and dim. I then installed the new light fixture. The ol ceiling rose had 3 live, 3 neutral and 1 earth going into a series o connector blocks. Since my new fixture only had 3 connections, twisted the old wires and connected them to the corresponding new one

- easy, right? Power on. Light came on but dimmer switch wouldn' dim. Turned off the light at the dimmer switch and the fuse blew. Messed with the dimmer connections to no avail. Disconnected the ne light fixture. Now when I turn on the power, the fuse blows. I spen last night in semi-darkness and am now contemplating calling a electrician but would rather do this myself.

Anybody

-- Heather

[Tim Mitchell]

In article , Heather writes

connector blocks. Since my new fixture only had 3 connections, I twisted the old wires and connected them to the corresponding new ones

- easy, right? Power on. Light came on but dimmer switch wouldn't dim. Turned off the light at the dimmer switch and the fuse blew. Messed with the dimmer connections to no avail. Disconnected the new light fixture. Now when I turn on the power, the fuse blows. I spent last night in semi-darkness and am now contemplating calling an electrician but would rather do this myself.

Gorblimey, this question seems to come up every 5 minutes. If you use google groups and search for "ceiling rose" you will find a zillion answers, but the short version is, one of the "neutral" wires is actually a switched live from your dimmer switch and would have been connected to one side of the bulb. The red wires are unswitched live.

When you clicked your dimmer switch you were actually turning it on not off and you shorted out live and neutral hence the fuse blowing.

You need to find which red wire goes to the dimmer switch and which black wire comes back from it (you will probably need a multimeter for this). Then connect all the reds together, the other blacks together, and the black from the dimmer to the light bulb.

Next time, note down what is connected where before disconnecting!

(PS I think calling the electrician is a good plan)

[brugnospamsia]

The new lamp isn't a compact fluorescent light by any chance was it ?

(and you want to trace the wires back to the terminal blocks and attach them properly once you've made it work)

Jeremy

[bigcat]

problem -

Indeed. If youre competent to do so, which I am not so sure of, one coudl disconnect all the black wires and use a lightbulb to find out which one is what, then reconnect correctly. 2 will be neutral, one will be switched live. A bulb lights only when it gets live on one side and neutral on the other.

NT

[John Rumm]

That is your problem....

Three lives should be common, but only two of the neutrals! (because one is actually a live on its way back from the switch). It is current good proactice to mark the switched live with a red sleave or bit of red insulating tape in the ceiling rose so that it is easy to see at a glance which is the switch wire.

[Rob Morley]

Or live on one side and earth on the other (or two phases of a three- phase supply) (or between neutral and earth if it's a low-voltage bulb).

[Dave Plowman (News)]

You've had the answer about one of the blacks being a switch return and therefore a 'live' when the switch is on, but only one earth? There should be three earth wires. One on the feed, one on the loop to the next ceiling rose, and one to the light switch. Those should be linked, and fed to the fitting - if needed for the fitting. Sounds like you need pro help.