Rewiring the 2 way landing light switches. Have pulled
cables in new colours:
a) Brown/blue/earth from landing ceiling rose to switch carrying
live (brown) + switched live (blue with brown sleeve);
b) 3 way (new colours)/earth from 1st floor switch to ground floor
I can work out the connection diagram but have two
1. Is there a preferred way of using the colours in the 3 way
cable ie. which is the switched return?
2. What is the correct way to connect the switched return
from the ground floor switch to the switched feed to the rose
(blue + brown sleeve) in the wall box behind the switch? The
old wiring had one of those screw-on "hats" - which I've lost.
Hope this makes sense, (and yeah it's all gonna get checked
and signed off by a sparks!).
Not sure if there's a "standard", but IIRC it's usually yellow. In any
event, I'd put brown or red sleeve on each of the 6 ends.
Again, not sure what regs say, but I would just pair up each of the two
"non-yellow" wires with one of the two feeds from rose - thus two wires in
each screw-hole thingy. Each copper core is only 1mm (or sometimes 1.5mm)
so should fit easily.
Clever bit is ensuring light is off when both switches are "off" or both
"on" - if you care for that kind of symmetry...!!
Sensible that you're going to get it checked if you have any doubts.
Re your problem
You say you have 2 cores +earth from ceiling rose to landing switch and
3core +earth from landing switch to downstairs switch.
If this is the case wire up as follows:-
Look at switch and you will see 3 connections com, L1 , L2.
Downstairs connect 3 wires one to each (their is no hard fast rule for new
colour code yet) .I use brown comm , L1 grey , L2 Black.
Upstairs connect the colours the same.
Now take the twin brown feed wire from the rose (in your case brown/blue)
and put one core in each of L1 and L2.
No need for connectors or anything .
BTB if you want symetry of switching just change the wires in L1 and L2 at
the downstairs switch if not correct.
You don't need any connector blocks etc - see below for the preferred way.
You'll need to set your newsreader to a fixed font to see the diagram
0===========0 0===========0============= Line
| \\ / |
C 0================================O C
\\ / \\ /
0===========0 0===========0============= Switch return
L2 Optional L2
He who laughs last, thinks slowest*
Dave Plowman firstname.lastname@example.org London SW
Surely the best way to determine colours is to look at what has been
done elsewhere in the installation using old colours and then do a 1:1
map onto the new colours as defined for 3 phase wiring. This would mean
Red = Brown
Yellow = Black
Blue = Grey
Black = Blue
This way you should have consistency between old colours and new
colours at any point in the system and no-one should have a problem.
Regulations don't specify a particular way but as a previous poster
said all lives/switched lives should be marked with brown tape or
Thanks to everyone - simple when it's explained :)
So since all the cores in the 3 way cable are potentially
live, depending on the switches, both the Grey and Black
should have brown sleeves at both ends. I'll assume
that unless anyone says otherwise.
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