Regular question:- How does one wire a ceiling rose?
On to the real wiring the switch wires should be both red/brown or at least
have a red/brown sleeve but in practice this is rarely the case. Where red/brown
and black/blue are used the sleeve on the black/blue often falls off or was
never put there in the first place. If the ceiling rose is removed without
noticing which is the switch wire. This is how to work out which black/Blue wire
is which when all three cables are the same colours. These are:-
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.
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. Starting with power off.
- With power off connect all cables except for neutrals and switch cable
i.e. Reds/Browns centre and Earths to clamp and lamp it's self to outer two
connections. The black/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 it. If it
works jump to 4. If not turn off power.
- 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
- Swap the wire in spare block connector with other black (or blue) in ceiling
rose. It should now work when switched on again. If not there is another fault
not at rose and it is beyond this simple check.
- 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.
- 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.
Next we look at two position switching.
||As school boys were were shown the diagram on the left. This of
course works well but in practice the cables do not go round in a circle
but go from the fuse box called a consumer unit to the first light the
then from that to switch and second light and so on so each ceiling rose
has three cables, when two or more switches are used it goes from first
switch to second and so on. The diagram to left will require a
connection inside the switch so we use the second diagram to right with
this we can use the switch to make all connections. It will be noted the
live feed goes to both switches when the second switch is part of a two
switch arrangement sometimes the live is bridged from other switch so
only twin and earth is required.
Note1:- Years ago there was a method used that only had two wires between
switches and the line was taken from an adjacent switch. This has two problems.
It can cause mains hum on radios etc. and it can lead to a shared neutral
situation if the adjacent switch is not from same supply.
Note2:- Many call
two position switching "Two way switching" as the switch used has two ways.
However with three position switching the change over or intermediate switch
does not have three ways so the terminology then becomes confusing.
Note3:- Today there are radio controlled switches
the luminite easyswitch is an example. As a result there is no need to hard
When we move to three position switching we use a special switch called an
intermediate between the two position switches here we normally do use one block
connector inside the intermediate switch which will connect the bottom wire in
the diagram below.
Some times the 2 two position switch cables are returned to ceiling rose and an extra
connector is used below is how wires are run.
all diagrams earths have been missed out for clarity.