3 way help please.

[montrose]

Feel like a complete muppet, but replaced a 2 way switch in circuit with 3 switch one lamp.
Pretty sure the switch had single cable L1 single into L2 and two cable into comm, but this could be where I went wrong.
It is wired with 2 core and earth.
Circuit no longer works, on closer inspection all switches 2 way, ie no intermediate.
Cant find wiring diagram to help. ie 3 way with 3 2 way switches.
Pretty sure I rewired switch as before but no explanation for not working other than I mucked up.
Would appreciate any advice
Cheers
Kermit

 

[ericmark]

Diagrams on my web page http://www.ericpalmer.fsnet.co.uk/Lighting.html the problem is the way we do two way lighting in UK is completely different to how it is done in USA. Both work but if you use USA system you need junction block in switch.
Originally our method was to save on wire as you can use twin core between switches but it was found this caused EMC problems and has been dropped now.
Eric

 

[montrose]

Thanks Eric
Not sure if I can see what I am looking for in your page.?!?!
One of my switches does have a connector block in it however this was just tying off a single cable. There was another cable which was loose, (as many have been when I have removed front plates) same colour, this was hanging around the L2 for that switch, should it have been in the connector block, that would leave one switch with only comm and L1.
The other 2 with L1, L2 and comm all used.

Cheers
Elmo

 

[ban-all-sheds]

Circuit no longer works, on closer inspection all switches 2 way, ie no intermediate.
Cant find wiring diagram to help. ie 3 way with 3 2 gang switches

You can't do 3-way switching with only 2-way switches - one of them has to be an intermediate...

 

[ericmark]

Sorry you have not been able to work it out. Any feed back as to why will help in redesigned page.
Returning to original post for non two way switching you need one wire in Com and one wire in L1 (or L2). Normally there would not be any more than two wires going to any one way switch.
For a two way switch the pair of wires goes to L1 and L2 and the triple cable goes one into each hole (So two wires in L1 and L2) and the same colour goes into same hole in other switch of the pair. (So is red is in Com on one switch red also goes to com on other switch) Second switch only one wire in each hole. See centre lamp in http://www.ericpalmer.fsnet.co.uk/Images5/LIGHTS.JPG
Now in old houses there was a cheat where instead of using three cores between both lamps the live was linked. If the switch in first lamp shown was on same plate and lower switch of second lamp shown then instead of running the right hand wire between the two two way switches one could link the live from other switch. Although this works it also creates a loop where the out going wire does not follow the same path as return and as a result can impose mains hum on hi-fi etc. Also on stairs if lighting circuit split between upper and lower floor it can result in borrowed neutrals. As a result this is no longer done. See http://www.ericpalmer.fsnet.co.uk/Images5/Two-way-UnBalanced.JPG the top wire of three going through loop is dashed to show not connected.
However if you already have this system you need to know which is strapper wire between both switches and which is wire connecting wire to lamp.
If you place one set of wires in junction block and other connected com and L1 and test one set will do nothing these will be strapper wire and the other will switch lamp. From the switch I would assume red would be line all the time so I would put that in L1 on it’s own and then place two blacks together in L2 remaining red into com. On other switch red to com and black to L2 then link wire from L1 to line on other switch.
Does this make sense and if you do under stand where did I go wrong on web page.
All best Eric
PS did I miss read question or has BAS miss read question?

 

[montrose]

Ok thanks, but now my heid hurts

Think B-a-S might be right, but cant see how it was working before replacing switch. Think this described on other site as 4 way circuit? 3 switches and lamp?

I have 3 switches in total, 2 upstairs one downstairs, one lamp.

However circuit had only 2 way (L1 L2 and com) switches no intermediate.

Switch i replaced (upstairs) had three terminals - 2 times single red wire and 2 black joint in other port. From one white and one grey twin and earth.

Downtairs switch has twin and earth grey, red in L1 black in L2 and additional heavier red cable (with additional red sleave) in com (not seen again?- but suspect that it could appear in second upstairs switch as white twin and earth)

Second upstairs switch has 2 white twin and earth - reds into com and L1 one black in unconnected connector, the other black was swinging free when took of plate, so could have been either in with other black or in L2.

Lamp has single grey twin and earth.

Unfortunately I binned the switch I replaced, but there was no doubt that it only had 3 terminals. the other are still original 2 way (L1 L2 and com).

Any further insight would be appreciated.

Cheers
Bert and Ernie

 

[ban-all-sheds]

I think that until you straighten out the confusion in your mind between a 2-gang switch and a 2-way switch we're all going to have problems...

 

[montrose]

Yep, sorry, had realised I confused every one.

Switches are all 2 way single gang and 3 in total.

Cheers
Fuzzy

 

[ban-all-sheds]

So before you changed anything you had 3 switches all controlling 1 light, and you could turn the light on and off from any switch no matter what position the other switches were in?

 

[montrose]

Exactly.

Now have circuit where one switch will not turn on or not turn off light. This switch is not the same one each time.

Thanks for your help so far.

 

[ban-all-sheds]

And all 3 of the switches you had before were 2-way, none of them was an intermediate?

 

[montrose]

Yep, no intermediate. All switches with 3 terminals only!

 

[ban-all-sheds]

Were any of them spring-loaded - i.e. you press the rocker but as soon as you take your finger away it returns to the original position?

 

[montrose]

Nope, all appeared normal toggle switches, metal georgian rope design, age unsure but would reckon 15-20.

 

[holmslaw]

..