Dodgy switch?

[Scoter1066]

Hi

Completely rewiring a big old manor house at the moment, and this has me puzzled.

I have a corridor with a bathroom halfway down it, and a bedroom at the end of it.

At the top of the corridor I have a 2 way switch, into an intermediate switch outside the bedroom, then ending with a 2 way outside the bathroom. The feed comes into the switch at the top of the corridor.

So I have feed into L2 in this switch, and live to the corridor lights out of L1 at the other end. Black sleeved brown in the common.

When livened up , all switches will turn lights on/off individually, the two way works and so does the intermediate. But put the intermediate into a different position and the two ways won't turn the lights off!

Obviously, my first thought was that the intermediate switch was duff, so swapped it for another in another part of the house (wired up exactly the same way and working tickety-boo) but still the problem persists.

I've had the switches apart in all three positions convinced that I couldn't see the wood for the trees, but there is no boo-boo on the wiring.

As the house is still being refurbished, I had ply and plasterboard off the walls to see if the 3c&e cable had been knicked so that it was picking up a live off of another circuit, but cannot see any damage to cable at all.

I didn't have my multi function tester on my van yesterday so I haven't meggered out the 3c yet just to make sure, but I will first thing Monday, but with a continuity tester I could see that 3 strappers were live through the intermediate switch in one position, but only two in the working properly position.

Hope that makes sense. Oh, it's Knightsbridge Chelsea flat plate too - and don't get me started on that junk!!

Am I missing something here??!!

 

[Scoter1066]

Sorry - forgot to say that my next port of call will be two swap the switch outside the bathroom in case that is the culprit.

 

[flameport]

The intermediate switch is being connected to the wires incorrectly.
Most likely is that two of the wires of the same colour are interchanged.

 

[333rocky333]

What is the third terminal on the two way switch
L1 and L2 sometimes vary withdifferent makes

 

[Scoter1066]

The intermediate switch is being connected to the wires incorrectly.
Most likely is that two of the wires of the same colour are interchanged.

That was my initial reaction as it was wired by my junior, but not so. 2 x 3c&e, both commons in a block, both greys in L1, both browns in L2 and definitely one cable top, and one in the bottom.

 

[Scoter1066]

What is the third terminal on the two way switch
L1 and L2 sometimes vary withdifferent makes

Common in the top, one strapper in L1 on its own, the other strapper in L2 along with the live to the lights.

I should also mention that the end terminal is a 2 gang, fed on the non-2way side that does the bathroom lights, shaver light, and the 3C to the fan isolator, but I am 100% convinced no cables have been swapped about in that switch.

 

[riveralt]

What continuity reading did you get?

What about polarity?

Have you broken the circuit down and tested each element?

When faced with lighting conundrums I find it helps to draw out the circuits as you expect them to work.

 

[333rocky333]

I would try removing the intermediate switch for now and link the strappers straight through, if the two way then works ok, then it must really be the intermediate switch faulty or connected wrong,
Itwill also make it easier to check continuity between switch to switch.

 

[securespark]

Yeah, my money's on the int. wired up wrong.

 

[electronicsuk]

So I have feed into L2 in this switch, and live to the corridor lights out of L1 at the other end. Black sleeved brown in the common.

That's a bit of an odd arrangement, isn't it? Feed into L2 on one switch plate and S/L out on the switch plate at the other end of the corridor? Or are you actually saying that the feed and S/L are both at the same, single switch plate, as they should be?

Just a little confused by your use of "...at the other end...".

 

[Adam_151]

So I have feed into L2 in this switch, and live to the corridor lights out of L1 at the other end. Black sleeved brown in the common.

That's a bit of an odd arrangement, isn't it? Feed into L2 on one switch plate and S/L out on the switch plate at the other end of the corridor? Or are you actually saying that the feed and S/L are both at the same, single switch plate, as they should be?

Just a little confused by your use of "...at the other end...".

Though if he has, it will exhibit the exact behaviour that he has described in his opening post...

OP, what you need to do is feed into common of one 2 way switch, switch wire out to the light to common at the far end 2 way switch, and then pick the two cores of the 3+e that run through the intermediate switch (ignoring and not using the one which is joined straight through) and have one of these running from L1 at one end to L1 the other end, and the other L2 to L2

 

[electronicsuk]

Though if he has, it will exhibit the exact behaviour that he has described in his opening post...

The thought did cross my mind, but I thought I'd confirm, as my theory doesn't sit well with this:

That was my initial reaction as it was wired by my junior, but not so. 2 x 3c&e, both commons in a block, both greys in L1, both browns in L2 and definitely one cable top, and one in the bottom.

I can't see why you'd go to the effort of installing 3C+E and linking the commons at the intermediate switch if you intend to do 3-way switching using the 'singles method'.

 

[Adam_151]

I can't see why you'd go to the effort of installing 3C+E and linking the commons at the intermediate switch if you intend to do 3-way switching using the 'singles method'.

Lack of knowledge of anything but the 'conversion method' , its generally used exclusively on new installations when wiring with insulated and sheathed cables

 

[333rocky333]

OP, what you need to do is feed into common of one 2 way switch, switch wire out to the light to common at the far end 2 way switch, and then pick the two cores of the 3+e that run through the intermediate switch (ignoring and not using the one which is joined straight through) and have one of these running from L1 at one end to L1 the other end, and the other L2 to L2

It seems to me he needs the feed to go to "The other end" to supply the Bathroom light though, he would need to use a strapper as he did to do this, if he then fitted an intermediate that would bugger that up though when it switches diagonally across the strappers.

He could still use the spare core for the live though i suppose

 

[Scoter1066]

I would try removing the intermediate switch for now and link the strappers straight through, if the two way then works ok, then it must really be the intermediate switch faulty or connected wrong,
Itwill also make it easier to check continuity between switch to switch.

I have and it does.

Thanks for everyones' input but I have sussed it out. In drawing out the layout when the int switch is in a certain position it causes a permanent feed to the end of line switch

Will have a jig about at the int switch, and if I still can't rectify it, I'll move feed into the common one end, dispense with the current common core, and live to the lights out of common the other end just using the strappers as I would if I was using singles.

BTW - I hate Chelsea flat plate

It's the only crap thing I can think of with the word 'Chelsea' associated with it