Problem with 2-way switch

[brightandwild]

I had to buy a switch to replace the old one.The markings on the old one were L1,L2 & L3. The new one is L1,L2 & COM. As I don't know anything about electricity I naively assumed L3 = COM.A big mistake. After 14 hrs I got the lights working but not correctly. It is a switch plate with 3 2-way switches.One is required as a 2-way switch, the other 2 are used only as 1-way switches.The two 1-way switches are working fine when the 2-way is in the OFF position.This 2-way switch can be then controlled from the other switch downstairs. But when the 2-way switch is ON, then all three bulbs controlled by the 3 switches come on together.
Another problem is, for the 3 lights, 6 wires are in red.One is blue and one is yellow.
Can someone please advice what to do?Thanks

 

[pcboffinuk]

Hi Bright,

You aren't the first to discover that there are two or three 'standard' ways of marking light switches.

To give detailed advice, a diagram or picture of the back of the switch would help, showing the cables, colours of core wires, etc.

If I read your post correctly, you will have 2 cables coming from the 1 way switched lights, each with 2 red and earth cores. These should connect into the COM and L1 on the relevant switches.

If you remove the downstairs switch you will probably find there will be red, yellow and blue wires connected to the back - note which holes they go into and replicate upstairs (remembering that if the downstairs one is also L1, L2 and L3 then upstairs that becomes COM, L1 and L2)

There will also be a cable from the '2 way' light, which again may be red/red - if that is upstairs then it should connect between L1 and L2 on the 2 way switch. (you shouldn't need to touch anything on the downstairs switch, just note what is there)

However, if you can post a diagram or describe what you have exactly, then it will be easier to confirm.

I presume you have isolated the lighting circuit before carrying out this work, as 3 of those wires will be live (I guess if you hadn't you wouldn't be here asking the question though )

Gavin

 

[brightandwild]

Thanks a lot Gavin.I will take a picture tonight and post it.You may have guessed by now that I am woman and this is my very first attempt at doing something like this. Let me try to explain. Say the 3 switches are called A, B and C. A is the switch which is the landing light, meant to be working 2-way.I have connected a yellow and red in COM, a red in L1 and the blue and a red in L2.one small red wire connecting L1 of A to L1 of B and another small wire conencting L1of switch B and L1 of switch C. Two other red wires go in Com of switch B and C respectively.There is also a red wire going in L1 of switchC.Makes any sense at all?
not sure how to insert images.
Thanks again.

 

[pcboffinuk]

Bright,

Click here for some details on how to insert an image in a post.

No reason a woman shouldn't be able to do electrics

Though you've chosen one of the more difficult wiring problems to start your sparks career with!

You are not too far from the right layout, but some of the reds are in the wrong place.

If I've read things correctly, you only need to move the red from COM on switch A, to L1 on Switch A.

If that fixes switch A, but then switches B and C don't work, then the short wire from switch A to B will need to go from L2 in switch A to L1 in switch B.

Are the red wires combined in the incoming cables in pairs, or are all the red wires single?

If that doesn't fix it, then a pic or diagram might clarify things.

Gavin

 

[brightandwild]

Hi Gavin

Made another change last night and this is the situation now:
SWITCH A (2-way)
L1: YELL OW AND RED
L2: blue and red
COM: ONE RED only

SWITCH B
L1: one RED only
L2:
COM: Loop wire from COM of Switch-A only

SWITCH B
L1: one RED only
L2:
COM: Loop wire from COM of Switch-B and another red wire


(I have also checked the downstairs connection for the 2-way hallway light. It has one red in L1, the blue in L2 and the yellow in L3.)
Switch B and C are working fine. When the downstairs switch in ON, the upstairs switch A is working normally. But when the downstairs switch in the OFF position, the light comes on and the upstairs switch cannot control the hallway light anymore, which means there is a constant connection. Am I right in thinking, that I have wrongly connected the yellow downstairs to the red in COM upstairs?
What am I doing wrong?
I have also noticed that the red wire connected to the COM of switch C actually doesn’t make any change at all. Not sure what that wire is for?

 

[brightandwild]

I am trying to insert the diagram.Hope this clarifies the scenario.

Thanks again

 

[brightandwild]

May be this is a clearer picture.
Any input would be great.Thanks

 

[pcboffinuk]

Bright,

Thanks for the diagram, I think I have it now

If I'm right, the following should fix the problem.

The red in COM, switch A needs to be switched with the red in L1, Switch A.

That will fix the 2 way switch, but you will also then need to move the short wire from COM Switch A to L1 Switch A (it can remain in COM Switch B). That should ensure the other two continue to work correctly.

If the diagrams are right, you also have the Yellow and Blue in Switch A reversed, although it shouldn't affect the function of the switch.

The outgoing wire from COM Switch C is a permanent Live so it may be providing power to another light nearby? If you take it out you will probably find something else in the vicinity doesn't work.

Hope that resolves it, if not then come back and I'll scratch my head some more

Gavin

 

[securespark]

If the other two way switch has red in common & yellow/blue in L1 & L2, then fit the wires in the same terminals on the other switch.

Make sure the R/Y/B come from the same cable.

Then you have a bit of detective work. Sort the remaining reds into which cable they come from. I guess there may be two twin reds and one red single.

You need to find out which is the live feed, or feeds.

If you have two twin reds, then one I guess will be the feed & switchwire for the 2 way. Turn off the power, connect the pairs of reds together and switch on. If they are switchwires & feeds, then two lights (or sets of lights) should come on. The pair that turns on the light you want 2 way must be connected to the yellow / blue terminals.

The other twin red should be another live & a switchwire, and you should have been able to ID which light from the previous exercise.

You just need to ID which red is the feed. This then loops between the two one way switches. The remaining two reds each go in one L1 terminal of the one way switches.

My guess is that the one way lights & two way lights are on different circuits. If this is the case, do not mix them up.

Hope this helps, not hinders...

EDIT: I seem to have interpreted it differently...

But if your idea is right, pc, what do you do with the extra red?

 

[brightandwild]

unfortunately Gavin your method still didn't get it right.So I swapped the red wires of L2 and COM in switch A. And looped L2 to COM of Switch B.It is working perfectly fine.My first venture is now successfully over. Thanks for your help.

 

[securespark]

It may work, but it doesn't seem right.

Can you tell us how many cables (grey or white sheath) there are at the switch & how many conductors of what colour there are in each? Omit the earth wires.

 

[pcboffinuk]

Ok, that was my next guess

Actually drawing it out I can see it works - I got the switched live and the strapper to the switch downstairs round the wrong way.

Still not sure if these are singles or twin red cables, but it seems to show a drawback of twin red or twin brown switch drop cable? Sleeved (or even unsleeved) black or blue cables would have made the identifying a whole lot easier....

I guess the stray wire at Switch C must be passing on a live feed to some other local accessory, in which case securespark may be right to worry about different circuits - there could be a borrowed neutral somewhere.

Glad you got it working anyway

Gavin

 

[brightandwild]

After reading all the posts, I got a quaified electrician to have a look at the switch.He confirmed that it is correctly connected. So now I am relieved. Thanks again.