i need advise on wiring a ? 2 gang light switch

[ric4047]

Hi,
I have what i think from your wiki section may be a 2 gang light switch in my kitchen beside the patio doors into my garden. This 2 ganger has 2 ?switches (not sure of terminology here)on the front of it. one switch is a 2 wayer for a light in the middle of the room- the other switch for the same light is on the other side of the room--both can turn this light on/off.
The other switch on the 2 ganger is a one way switch for a light outside the house on the wall facing the garden.
recently the outside light wouldn,t turn off so i took the 2 gang switch off. stupidly i paid no heed to which wires went where. i have no idea how to rewire the damn thing.
looking at the wires--there are 4 reds(?all live then) and 1 earth(which is not a prob--i've left it alone where it was). 2 reds come out of 1 thick grey shealth and the other 2 come out of their own grey sheaths.
what i assume is a 2 gang light switch looks like your drawing of the back of a 2 gang light switch in wiki except that both black parts are facing the same way--both commons are beside each other at the top and there are 2 places at the bottom of each black part ? called L1 and L2--4 in total beside each other and they say 1 way and 2 way for each pair. can anyone guide me. i am an electrics novice--i can only wire a flex to a ceiling rose and wire a plug--thats my limit at present. thanks
ric
ps--i forgot to say the light switch on the other side of the room has 3 switches-- 2 are i wayers and i is the 2 wayer i mentioned above. the 2 wayer here also currently doesn't light up the light its meant to.

 

[ban-all-sheds]

Hi,
I have what i think from your wiki section may be a 2 gang light switch in my kitchen beside the patio doors into my garden. This 2 ganger has 2 ?switches (not sure of terminology here)on the front of it. one switch is a 2 wayer for a light in the middle of the room- the other switch for the same light is on the other side of the room--both can turn this light on/off.
The other switch on the 2 ganger is a one way switch for a light outside the house on the wall facing the garden.

Yup - that's a 2-gang 2-way switch (2-way switches can always be wired to use as 1-way, which is what one side of yours has been.)

recently the outside light wouldn,t turn off so i took the 2 gang switch off. stupidly i paid no heed to which wires went where.

Oh dear.

there are 4 reds(?all live then)

Not permanently.

and 1 earth(which is not a prob--i've left it alone where it was).

Where was/is it? This is important. It seems reasonable from your "left it where it was" that it was connected to the backbox, not the switch, but it's be nice to have confirmation.

2 reds come out of 1 thick grey shealth and the other 2 come out of their own grey sheaths.

And the earth comes out of the same sheath as the 2 reds?

And there really are no other cables - not even a short one on the switch linking the two COMs?

what i assume is a 2 gang light switch looks like your drawing of the back of a 2 gang light switch in wiki

"2-gang" means that there are two switches in the same unit, so it has 2 sets of terminals on the back, and 2 rockers/toggles/knobs/whatevers on the front.

"2-way" means that each set of terminals consists of a COM and an L1 & L2. COM is connected to either L1 or L2 depending on the position of the rocker/toggle/know/whatever, which means it can be used so that 2 switches in 2 places can control a light irrespective of the position of either switch rocker:

except that both black parts are facing the same way--both commons are beside each other at the top and there are 2 places at the bottom of each black part ? called L1 and L2--4 in total beside each other and they say 1 way and 2 way for each pair. can anyone guide me.

PROBABLY each L1/L2 matches the COM above them, but...

In the same way that your toolbox contains screwdriver, not pointed knives, as they are the right tools for dealing with screws, and a hammer instead of a lump of rock, as that's the right tool for dealing with nails, it now needs to contain a multimeter, as you need one if you're going to deal with electrical wiring.

With one you'll be able to confirm which switch terminal goes with which.

the 2 wayer here also currently doesn't light up the light its meant to.

On the face of it you don't have enough wires for a 1-way and a 2-way on that 2-gang, but if it worked before....

The multimeter will allow you to identify permanent and switched lives....

 

[2scoops0406]

Good advice indeed, get yourself a multimeter, you can get a perfectly serviceable one for not much more than a fiver from Wickes (other outlets have em as well)

 

[ric4047]

yeah the earths on the back-box

 

[ric4047]

and an earth comes out of each of the three sheaths. incl just one earth for the sheath with 2 red wires

 

[ric4047]

there is a short eg 5cm length which i think connected between 2 points. sorry , forgot about that

 

[ric4047]

thanks for all the info. i'll get a multimeter . will 2 red wires turn out to be lives and 2 coms

 

[ban-all-sheds]

You mean 2 permanent lives and 2 switched lives (COM is not a conductor function, just a label on a switch terminal. Sometimes instead of COM/L1/L2 you get L1/L2/L3).

You might find that.

[EDIT]
If you do, and without any other wires, I can't see how you could ever have had 2-way switching on one gang....

My apologies - I didn't see your post about the wire linking 2 terminals.

As Rocky says, you've almost certainly got 1 permanent live - this will go into one COM, which will be linked to the other.

The switched live for the outside light will go from one L1, the other two wires will go into the other pair of L1&L2, to get 2-way switching as per the 3rd method shown here.

You just have to find out which wire is which. This will involve testing live cables - be careful...
[/EDIT]

 

[333rocky333]

Proberly will find only ONE red is perm live which will link across with your short piece to the other section to provide a live at both sections of the switch,one of the other reds will then go on the output of the ONE way switch for the outside light.

Com And L1 proberly used for the outside light

As you only have reds and no blacks to deal with should not be a problem providing you isolate each time.

If you find them two and get the outside light working you are halfway there.

The two remaining reds will then go one in each of the other holes of the TWO way switch.
Due to different ways of wiring, the connections on the two way may vary especially as it sounds like you have single double insulated cable in use .

Do you know what wire is used in the opposite two way switch connections as the L1 and L2 of that may possibly help you establish L1 and L2 at this end.

 

[ric4047]

i got a pocket digital mulimeter and i just don't have a clu e how to use this to determine which of the 4 reds are lives. help.

 

[ric4047]

it says in the instructions to turn the power off first to that circuit. but surely if i do that then all 4 wires will be currentless. do they mean --turn off the power, connect the multimeter and then turn the power back on then. plus the multimeter has numerous different figures on it on a rotary switch. which i do i put it to--eg--600,200,200(with a ?greek alphabet symbol like a 'u' with a downward bit on the lower right of the letter-- is it mu?),2m,20m,200m,10A,hFE,a symbol that looks like a loudspeaker symbol that the booklet says is for testing continuity, 200 again, 2k with another strange arrow with a line across it(book says this one is to test diodes),20k,200k,2M,200m,2,20,200 again, 600---all in that order .

near the last few-the 200m,2,20,200,600 there is a V (with a solid horizontal line and dotted horizontal line paralell to each other after the V) --therefore i assume these 4 positions on the dial measure dc voltage?

beside the other 600 and 200 there is another V with a sinusoidal/curvy line beside it--i think that means ac voltage?

the 200 mu,2m,20m,200m,10A are in the Asection--this A has the solid and broken lines like for the former V described above.

then there is a resistance section-- ohms symbol--for the 2M,200k,20k,2k and 200.

there are 2 test wires--one black ,one red.
there are three input sockets-- 10ADC, COM , and V(then ohm symbol)mA.
See what i mean. only an electrician could use this. i read the booklet which didn't explain how to use this device to test a wire to see if its the live one or not.

 

[ric4047]

i might just guess which is live. i only would need to try three combos. if none work it must be the 4th wire

 

[ric4047]

i read the booklet again--its sinking in now---there is a taking measurements section--one subheading is measuring ac/dc volts--i guess this is the bit i should follow--it says to put the black probe in COMM and the red probe in V(ohm)mA. i also now see that the wavey line means AC voltage and the 2 parallel lines ,one solid one broken/dotted means DC. therefore as all houses are AC i use the AC voltage section. there is only 2 positions to set the dial for AC voltage and that is 200 or 600. book says if i'm not sure use higher one. do most houses not have max 240 voltage? so do i turn mains off and wrap the copper ends around the probes and turn power on again? the probe ends are sharp spikes--i thought clamps at the probe ends would have made connecting easier.
or do i stick the sharp probe ends into the insulation of each wire until they touch copper?

 

[ric4047]

OR should i be measuring current rather than voltage to test which wire is live???? on the meter current seems to be DC only. is there no such thing as ACcurrent. i assume not. i thought it only applied to voltage

 

[ric4047]

I did it. i just tentatively touched both the probe ends against each of the 4 reds with the meter at 600V AC and 3 wires gave no reading and 1 gave a reading. so i followed your advise above incl connecting the loose piece of wire between the 2 comms and the live to the comm for the outdoor light and it worked 1st time. Thanks !!!!!!!