Complex intermediate switch question

[JosephandAmber]

I want three switches to control a light. All three switches are intermediate and so have four avaliable terminals. Switch 1, switch 2 and switch 3.

Switch 1 has the incoming live.
Switch 2 has the load (and is the true intermediate)
Switch 3 is a standard switch.

Can anyone advise on whether the below would work?

 

[DefyG]

Why complicate things and not change two of the intermediates for standard 2 way switch plates.
No it wont work.
It can be done using intermediate switches but you need to treat switch one and three as a standard 2way.

 

[JosephandAmber]

Why complicate things and not change two of the intermediates for standard 2 way switch plates.
No it wont work.
It can be done using intermediate switches but you need to treat switch one and three as a standard 2way.

The reason is that they are very expensive switches that were purchased by clients. Given that intermediate switches have the exact same functionality as two-way switches, only with a spare terminal I don’t personally see the problem?

 

[PS Electrics]

The reason is that they are very expensive switches that were purchased by clients. Given that intermediate switches have the exact same functionality as two-way switches, only with a spare terminal I don’t personally see the problem?

He said it can be done and I agree the two end switches will be wired as two-way switches.

It is your wiring I am having difficulty following. Is this an attempt to create 2 way and intermediate switching from existing wiring that didn't previously have it? Is one of the legs new? How come you have all four terminals used at Switch 1 for instance?

If so is there a reason you cannot run new cabling so it is standard? Doing it this way will be a nightmare for any future fault finding! The reason I suspect this is the case is that the switch line is at the intermediate switch.

Is there a way for you to sketch this out on a bit of paper and then scan it or take a picture? It will make it a bit easier to see what exactly is going on.

 

[DefyG]

Given that intermediate switches have the exact same functionality as two-way switches, only with a spare terminal I don’t personally see the problem?

They dont have the exact same functionality as two way switches because if they did a 2way switch you could argue could be used as an intermediate switch which of course it cant.
An intermediate switch can be used as a 2 way but your drawing wont work as you show amongst other things all 4 terminations in switch one connected which of course cant happen if its a 2way switch that only has 3 terminals.

 

[JosephandAmber]

Ever seen an intermediate marked like this before? I think this is what's confusing me.

 

[littlespark]

is that the switches you're working with? Intermediates are usually marked 1,2 at the top and 3,4 at the bottom... or L1, L1, and L2, L2....

If theyre all the same.... ill try to draw out what you described in first post.

Its true that intermediates can be used as a two way, and a two way can be used as a one way..... but obviously not vice-versa.

 

[mainline]

Ever seen an intermediate marked like this before? I think this is what's confusing me.

View attachment 118734

 

[littlespark]

It is actually much more straightforward than it appears.

youve got 3 switches, a 3 core and earth between switch 1 and 2, and another 3 core and earth between switches 2 and 3.

Taking the terminal njumbers you have supplied.... which isnt waht we were expecting, TBH

Switches 1 and 3 are intermediates, but will be working as 2-ways.... Ignore terminal 4 on both these switches to make it easier to understand.... and terminal 1 as the two-way Common.

Switch 2 is the true intermediate.

take both browns in the 3 cores to the common in switch 1 and 3, and joint it through in switch 2.... do not connect it to the intermediate switch. Just stick them in a Wago together... nothing else.

Grey and black are the travellers.... or strappers, or pass wires... whatever you want to call them
on switch 1 and 3, the two ways... put them into 2 and 3....
on switrch 2, the intermediate .... put the grey and black from switch 1 into 2 and 3.... and the grey and black from switch 3 into 1 and 4

You now have to connect the live feed and the switchwire out.... which can be connected to either a grey or a black traveller at any of the switches... (but obviously not the same one at the same switch)

 

[DefyG]

It is actually much more straightforward than it appears.

youve got 3 switches, a 3 core and earth between switch 1 and 2, and another 3 core and earth between switches 2 and 3.

Taking the terminal njumbers you have supplied.... which isnt waht we were expecting, TBH

Switches 1 and 3 are intermediates, but will be working as 2-ways.... Ignore terminal 4 on both these switches to make it easier to understand.... and terminal 1 as the two-way Common.

Switch 2 is the true intermediate.

take both browns in the 3 cores to the common in switch 1 and 3, and joint it through in switch 2.... do not connect it to the intermediate switch. Just stick them in a Wago together... nothing else.

Grey and black are the travellers.... or strappers, or pass wires... whatever you want to call them
on switch 1 and 3, the two ways... put them into 2 and 3....
on switrch 2, the intermediate .... put the grey and black from switch 1 into 2 and 3.... and the grey and black from switch 3 into 1 and 4

You now have to connect the live feed and the switchwire out.... which can be connected to either a grey or a black traveller at any of the switches... (but obviously not the same one at the same switch)

Very comprehensive but aren't there rules in the forum about 'not' giving 'step by step' guide advice to DIY'ers and the like?

 

[littlespark]

Very comprehensive but aren't there rules in the forum about 'not' giving 'step by step' guide advice to DIY'ers and the like?

Spot on....

Maybe i should delete it?


OP is a domestic installer, not a DIYer, according to profile.... so maybe just overthinking the switch wiring.

 

[brianmoooore]

aren't there rules in the forum about 'not' giving 'step by step' guide advice to DIY'ers and the like?

Yes, but this isn't at all safety related, or a 'what size cable do I need to feed my shed' type of query. It's help sorting out the connections to some oddly labelled switches, some of which aren't being connected as intended.
In all honesty, who amongst hasn't had to return to a newly wired two way and intermittent switch setup at least once in their career, to sort out the incorrect connections.

 

[JosephandAmber]

It is actually much more straightforward than it appears.

youve got 3 switches, a 3 core and earth between switch 1 and 2, and another 3 core and earth between switches 2 and 3.

Taking the terminal njumbers you have supplied.... which isnt waht we were expecting, TBH

Switches 1 and 3 are intermediates, but will be working as 2-ways.... Ignore terminal 4 on both these switches to make it easier to understand.... and terminal 1 as the two-way Common.

Switch 2 is the true intermediate.

take both browns in the 3 cores to the common in switch 1 and 3, and joint it through in switch 2.... do not connect it to the intermediate switch. Just stick them in a Wago together... nothing else.

Grey and black are the travellers.... or strappers, or pass wires... whatever you want to call them
on switch 1 and 3, the two ways... put them into 2 and 3....
on switrch 2, the intermediate .... put the grey and black from switch 1 into 2 and 3.... and the grey and black from switch 3 into 1 and 4

You now have to connect the live feed and the switchwire out.... which can be connected to either a grey or a black traveller at any of the switches... (but obviously not the same one at the same switch)

Thank you for this. I'm familiar with two way switching but as mentioned above, having to use intermediates has completely thrown me, nevermind the unusual labelling. I will do exactly as you have described and report back.

Just to be absolutely clear... what terminal are you taking the live feed at switch 1 into?

 

[littlespark]

Thank you for this. I'm familiar with two way switching but as mentioned above, having to use intermediates has completely thrown me, nevermind the unusual labelling. I will do exactly as you have described and report back.

Just to be absolutely clear... what terminal are you taking the live feed at switch 1 into?

the live feed can be on either of the traveller wires... so terminals 2 or 3 at switch 1

the switched live can come off any traveller at any switch.... so any grey or black core.... Except the same one used for the live feed.

as the switches are operated, the feed crosses over between the two travellers

 

[JosephandAmber]

I just wired the circuit exactly as you described and it works perfectly. Thank you so much for this. I really appreciate your help. I have no idea why my brain got so confused trying to work out the logic of the circuit but I’ve learnt a lesson and hopefully won’t have this problem in the future.