2 way switch wiring, all wires same color

dlldxb · Post by **dlldxb** » Thu Apr 01, 2021 1:14 pm

Hi

I am replacing a light switch on a 2 way circuit. All the wires are yellow except the yellow/green ground which seem to be the only one to code. On the first switch there are 4 other wires, which will be L1 L2 and common, but all are yellow. 2 have black tape, would this indicate they are the live? The wires were loose from the connectors so I cant backtrace where they were connected. I have pulled the other switch out and it has the yellow wire with no tape or marking whatsoever.

I come from a 110/60hz world so still getting used to UK wiring and lack of neutral (miss my Wemo's back home)

thanks

Scotty001 · Post by **Scotty001** » Thu Apr 01, 2021 3:43 pm

Where the wires were loose are the fully out of the connector so you have no way of telling which connector they were in?

Re the black tape being switched live, I would only hazard a guess as yes (it's only a guess) , simply because although there is nothing to say it must be wired this way with these colours, generally people stick to the what is expected and don't throw in the same colour wire for everything. Without the right test equipment / multimeter it's not going to be straight forward to find Out.

Others more knowledgeable (Inc qualified electricians) will be along to assist better than I, if you could post some pics of both switches and wires in site that will help them a lot.

dlldxb · Post by **dlldxb** » Fri Apr 02, 2021 7:19 am

photos of switches

Someone-Else · Post by **Someone-Else** » Fri Apr 02, 2021 7:33 am

Correct me if I am wrong, but do I see 4 yellow wires, two have black tape, and two are just plain yellow?

Is the switch in the picture the new switch? or is it the old switch?

Before you did anything, could you turn the light on/off at say, the bottom of the stairs, the top of the stairs AND on the landing?

If that switch is the new switch, do you have a picture of the old switch ? (If so, does it have 4 terminals?)

dlldxb · Post by **dlldxb** » Fri Apr 02, 2021 9:45 am

switch in picture is the other switch but both are same. Before light was working, but then stopped. So i am assuming when painters pulled covers, wire came loose. Yes all are yellow except the ground, The black tape I am assuming is the live

Someone-Else · Post by **Someone-Else** » Fri Apr 02, 2021 10:13 am

Sorry, but you are there I am not, so.............

What do you mean "other switch"

Also, when everything was working, how many switches/places were there that you could turn the same light on and off from? Oh, pull cord switches count too.

Someone-Else · Post by **Someone-Else** » Fri Apr 02, 2021 10:23 am

To expand on what I am thinking.

You have 4 wires at one switch (Not counting earth) We don't normally have 4 wires for one switch, normally it is just 2 or 3 wires.
We do however have ONE "situation" (For want of a better word) that does require 4 wires, and it would be logical to mark just two of the wires, as get it wrong and it will not work.

Now the "fun" part.

I am guessing that all the switches were taken off at some point?

Take a picture of the back of each switch that was removed.

I am looking for a switch that has 4 actual terminals.

dlldxb · Post by **dlldxb** » Fri Apr 02, 2021 10:41 am

2 way wired switches

Someone-Else · Post by **Someone-Else** » Fri Apr 02, 2021 11:33 am

I am trying to help you.

As I said I am not there, so I (and anyone else) can not seek the information required for ourselves. If you continue to choose to give short statements and to ignore the questions fine, It is not possible to help you further.

dlldxb · Post by **dlldxb** » Fri Apr 02, 2021 12:44 pm

the short answer was to your question "What do you mean "other switch"" Its a two way switch circuit. the two pictures show switch in place and the wires of the removed switch. both switches are as the one shown. I am thinking that the un taped yellow wires were twisted together attached to common and the tapes are L1 and L2. Like i said both were "pulled away" for painting but only the switch with the 4 wires came loose.

like I said, i am used to standard American wiring, so the mono colored UK wiring is new to me

Scotty001 · Post by **Scotty001** » Fri Apr 02, 2021 4:59 pm

Dlld mono Coloured wiring is not standard, that's where part of this issue is, each wire should be a different colour but who eber installed it probably didn't have enough length of the correct cable so thought they would use anything to hand, in this case all the same colour.

This

Old wiring colours

Or this

New wiring colours

Is how it should look.
*Note if you have metal switch plates you would also connect the earth to the switch plate as well as the metal back box (if it's a plastic back box it won't need the earth connected to it.

https://www.flameport.com/electric/ligh ... twoway.cs4 gives a good description of how it should be and the colours.

Someone-Else · Post by **Someone-Else** » Fri Apr 02, 2021 5:31 pm

What the colours should be does not matter since it has already been wired using Yellow.

I can not help but wonder as it has 4 wires is it an intermediate switch?

Since the wires are all yellow, you have 2 choices. (As you may have guessed, yellow is not a standard colour on its own.)

1) Trial and error
2) Use a multi meter to find out what does what.

There is however a vague chance that one of the other switches may give a clue. Can you post a picture of the other switch please. (Not the front but the back with the wires connected.)

dlldxb · Post by **dlldxb** » Fri Apr 02, 2021 6:22 pm

thanks drawing you supplied is the first one i looked at, and yes the wire counts are different. ground does attach to plate. enclosed is the secondary switch

OnlyMe · Post by **OnlyMe** » Sat Apr 10, 2021 5:55 pm

Scotty001 I know it's a week old post and the OP will never get back. But this is a conduit installation and used the old colour scheme. Now whoever designed or installed it has used yellow as it's a 3 phase system and that lighting circuit was on the yellow phase. They almost certainly did not just use whatever cable they had to hand.

It would be typical on a conduit system for there to be 3 cores at one switch and 4 cores and the other switch. One switch would have perm live in and a perm live out to the next switch (in the COM terminal) plus two strappers to the other switch. The other switch would have the two strappers and one switched live (in the COM terminal) to the light fitting.

It's rare to see such things in a domestic property as they are not often 3 phase but not uncommon in offices and schools.

dlldxb · Post by **dlldxb** » Wed Apr 21, 2021 9:24 am

Got a multimeter and tested the marked wires. When connecting to either unmarked as common and the taped assuming hot, they test out as 2 way. I also found drawing for the house and enclosed the area

: Screen Shot 2021-04-21 at 1.15.14 PM.png (100.89 KiB) Viewed 3064 times

I am referring to.