Light Switches Not Doing What They Should!
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markbalham
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Joined: Sat Jan 12, 2008 4:50 pm

Light Switches Not Doing What They Should!

by markbalham » Sat Jan 19, 2008 1:17 pm

Have recently replaced old pendant light fittings in room 1 and room 2 with new lights and am very confused with what's now happening when the switches are turned on and off:

Swittch for room 1 works fine at all times apart from when room 2 is already switched on - at this point both rooms are on half-brightness.

The only time the switch for room 2 does anything at all is when room 1 is switched off - again resulting in both rooms being half-brightness. At all other times the light remains off regardless of switch position.

Having assumed the problem lies in room 2, I have tried all combos of neutral / live neutral wires into both live and neutral terminals of the light but to no avail.

Does anyone have any ideas how this can be rectified???

333rocky333
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Joined: Sun Nov 25, 2007 11:03 pm

by 333rocky333 » Sat Jan 19, 2008 5:35 pm

Look at old post on page 6
Starting ******SOME LIGHTS DIM *******
May be some help

ericmark

by ericmark » Sat Jan 19, 2008 6:13 pm

Look at projects page and also here in Blue Peter style is one I did earlier.
Regular question:- How does one wire a ceiling rose? The switch wires should be both red or at least have a red sleeve but in practice this is rarely the case. This is how to work out which black/Blue wire is which when all three cables are the same colours. These are:- The feed, The Switch, The next Lamp. Easy way is meter or buzzer across the cables with power all off and flick light switch until switch wire is found but often the DIY man has no meter or buzzer so next method.
Do not use energy saving bulbs as we need to be able to see bulbs working on half power use normal bulbs only. Do not use this method if you have dimmers or discharge lamps in any of the house lights.
1. With power off connect all cables except for neutrals and switch cable i.e. the black or blue are left disconnected. Put one into spare block connecter and other two in the two outer connectors of the ceiling rose i.e. one to each wire feeding lamp. Now turn on power and try if it works jump to 4. If not turn off power.
2. Swap either of two blacks (or blues) connected with one in spare block connecter and then turn on power again. If it works then jump to 4. If not turn off power.
3. Swap the wire in spare block connector with other black (or blue) in ceiling rose. It should now work one switched on again. If not there is another fault not at rose and it is beyond this simple check.
4. Turn off power again and mark cable in spare block connector with black or blue type or some other way to find it again. Then put it in spare hole with other Black (or blue) then turn on power.
5. Test all lights if all work OK then all is done on the other hand you may find odd things happening like with light you have been working on being switched on other lights don’t work and with it off the other lights work as glow only and light you were working on will also start to glow. If this is the case switch off power and swap the two unmarked black (or blue) wires. Now all should work.
So what are we doing? Well we can’t connect any of the three blacks (or blue) together as one is live when switched on so to start with we find out which wire connects to the next rose in circuit by time 1, 2, and 3 have been completed we know this is wire is spare block connector. At this point, we don’t know which of the other two blacks (or blue) is neutral and which is the switch wire. But if we connect the next lamp in series to switch instead of neutral it will do no harm but the next lamp can only get a return through the lamp in the light we have been working on so either the one we were working on will come on dim or the next in line will come on dim which is all to do with what size bulbs are fitted. But we now know exactly which two wires are the wrong way around. So finally we have in the eight holes in rose (earths normally under clamp screw) Feed to lamp, Feed from switch, break, Three live wires at all times all red or brown (one feed, one out to switch and one to next lamp), break, Neutral (in or out), Neutral (out or in), Neutral to lamp.

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