3 Gand 2-way Light Switch Problem

[BertC]

Could some kind electrical expert possibly help me solve a problem? In the inner hall of my bungalow I have a 3-gang 2-way light switch that operates a ceiling light in the inner hall, another one in the outer hall, a light in the loft, and an outside light at the corner of the bungalow. One 3-core and one 2-core cable (not counting earth wires) come into the switch box. The red and black of the 2-core cable are connected to the Common and L2 terminals respectively of the the right hand switch . This is the switch for the loft light - no problem. The red and blue of the 3-core cable are connected to the Common and L2 terminals respectively of the left-hand switch. The grey of the 3-core cable is connected to the L2 terminal of the centre switch. A short length of red cable joins the Common terminal of the left-hand switch to the Common terminal of the centre switch. The left hand switch operates the inner hall ceiling light. The centre switch operates BOTH the outer hall ceiling light and the outside light - i.e they cannot be lit separately.


My problem is that I want to be able to switch on the outside light without having to switch on the outer hall light. Ideally I would like to change round the wires so that, say, the left-hand switch turns on BOTH the inner hall and the outer hall ceiling lights simultaneously (no problem if they both have to be on at the same time), while the centre switch just turns on the outside light. Failing that, I would be happy to substitute a 4-gang light switch for the 3-gang one and wire one switch separately for each light. But I can't figure out how to connect the existing wires for either option. Is either feasible without having to cut another cable channel down my wall?



I assume incidentally that whoever installed the switch used the L2 rather than the L1 terminals just because they were easier to get to - it seems to be set up for 1-way not 2-way switching.


I can't see any sign of any other intermediate switches.

 

[ericmark]

I have already directed you to here and here as to ways to control lights without need to run cables in the wall.

You can look here to see how the B&Q unit works also here is a review.

 

[holmslaw]

..

 

[Electrifying]

Hi mate, you're looking in the wrong place - nothing you do with the wiring in the three gang switch will alter the fact that the outside light comes on with the outer hall.

The reason being is that the swap over work is required at the ceiling roses/light fittings.

The outside light has been wired from the switch-live and neutral of your outer hall light fitting.

The grey conductor is feeding these two - so nothing you do in the switch will alter the fact that they light up together.

 

[PrinceofDarkness]

Bert, you have enough wires at that switch position to fit a 4-gang switch for individual control of those 4 lights - without having to channel the switch drop. It's also quite feasible to use the existing 3-gang switch to control the two hall lights (together) and the attic and outdoor light separately.

This will require access and reconnection to the individual cores above the switch in the ceiling void or (perhaps the attic) via a suitable junction box.

Firstly though, you need to ensure that the RH switch (attic) and the two other switches are on the same circuit - this isn't difficult to do.
Secondly, you say that you have a 3-core&E cable with Red, Blue and Grey cores: Are you sure about this?



Lucia.

 

[BertC]

Many thanks for these incredibly swift and helpful replies. Sorry about the duplication with the other forum Ericmark. Before starting this topic here I had just posted some very detailed questions to you on the other one in response to your earlier helpful reply there. I thought I'd try this one as well just to get as much information into my head as possible and reduce the chances of my blowing myself up. Thank you so much Electrifying and Prince of Darkness for your helpul replies. The latter seems very much to confirm what Ericmark had told me on the other site. I'm a bit troubled though by your doubting that my 3-core really is red,blue and grey Prince of Darkness. I'll check again in the morning when I can get the power off and let you know.

 

[PrinceofDarkness]

Bert, the usual core colours for 3C&E are Red, Yellow and Blue for older cables - and Brown, Black and Grey for later cables.


I'm not aware of a cable with the combination of Red, Blue and Grey - and I doubt that anyone else here is, either.

However, as I said earlier, you have enough wires at your existing switch (regardless of their colour) to control four 1-way lights independently. It only needs one live feed and four switched lives after all, and you have five wires........



Lucia.

 

[ban-all-sheds]

The grey conductor is feeding these two - so nothing you do in the switch will alter the fact that they light up together.

Yes there is - he could easily change the wiring at the switch so that they don't come on together.

 

[Electrifying]

The grey conductor is feeding these two - so nothing you do in the switch will alter the fact that they light up together.

Yes there is - he could easily change the wiring at the switch so that they don't come on together.

I suppose he could make them not come on at all

If what I am assuming is correct (that the grey conductor is the switch live feeding, 1st the outer hall, then on to the outside light) I don't see how anything can be done at the switch to stop that.....it's one cable.

 

[sparkwright]

The one grey wire feeds both lights so you would have to separate it at a ceiling rose or junction box somewhere.

Some switches do use L2 as opposed to L1 for 1 way operation, such as the older MK ranges.

 

[PrinceofDarkness]

The 'Grey' if it it is indeed grey, is clearly a switched live - going by the O/P's description.

I suspect that he's mistaken - or colour-blind.

The fact remains that only five wires are required at a 4-gang switch: One live feed and four switched lives........


Lucia.

 

[Electrifying]

The 'Grey' if it it is indeed grey, is clearly a switched live - going by the O/P's description.

I suspect that he's mistaken - or colour-blind.

The fact remains that only five wires are required at a 4-gang switch: One live feed and four switched lives........


Lucia.

This is true, and he could, as you say, re-configure in the loft (or under floor boards) - but there's not much he can do at the switch.

 

[ban-all-sheds]

I suppose he could make them not come on at all

 

[PrinceofDarkness]

That's right, 'Electrifying'. The switch position would require only a minor alteration compared with the other alterations above.......



Lucia.

 

[BertC]

Many thanks indeed all of you for all these helpful comments. You've given me a lot to go on, and I obviously need to do a lot of crawling around in the loft to work out all my options and maybe get back to you for more advice. But I'm not colour blind Prince of Darkness; here's a photo of the red, blue and grey 3-core. Maybe somebody used foreign cable (US?) to do this bit of the wiring.
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