Intermediate light switch, wierd behaviour

[bobMuk]

Just had a look at an MK intermediate switch on my van, and the wiring does need rotating through 90 degrees

Hmmm... does it have 2 terminals labelled "1" and 2 labelled "2"?

 

[EFLImpudence]

Whilst it does need rotating 90° all you have to do is -

swap the blue of one cable with the yellow of the other cable.

 

[AdrianUK]

Guess its not so relevant now, since we have determined that the OP is using an intermediate switch & its been miswired ..... but just to point out that there is an 'old timers' trick of wiring a normal switch across the two travellers to bridge them together. This has the effect of overriding both switches & forcing the lamp ON. This was often used to override the staircase light control in a public area using a time clock ...... I also use the same trick to allow my intruder alarm to bring on the landing light in the event of an alarm.

 

[JohnW2]

Guess its not so relevant now, since we have determined that the OP is using an intermediate switch & its been miswired ..... but just to point out that there is an 'old timers' trick of wiring a normal switch across the two travellers to bridge them together. This has the effect of overriding both switches & forcing the lamp ON. This was often used to override the staircase light control in a public area using a time clock ......

As you say, not very relevant now - but, yes, I have seen that - and as I said early in the thread, the behaviour the OP was seeing was what one would expect if that third switch was simply joining the two strappers.

I also use the same trick to allow my intruder alarm to bring on the landing light in the event of an alarm.

Remaining on this tangent, in the very first house I owned, best part of 40 years ago, I replaced all the one-way light switches with '2-way' ones, and replaced the T&E wiring with 3C+E, arranged so that when switches were in the off position, the ('L side of the') light was connected via the switch to the third core of the cable. All these 'third cores' were joined together (these were the pre-singe-RCD, let also dual RCD, days). Activation of the intruder alarm (or a 'panic' switch - one by bed and one just inside front door) resulted in power being applied to that 'third core', so that virtually all the lights in the house would come on, whether they were switched on or off. To do the same today would obviously require the 'third cores' of circuits associated with different RCDs to be kept separate, but it could still be done with a 2-pole relay.

Kind Regards, John.

 

[EFLImpudence]

I didn't realise that was what you meant, earlier.

 

[JohnW2]

I didn't realise that was what you meant, earlier.

Is that a reference to my recent statement:

...and as I said early in the thread, the behaviour the OP was seeing was what one would expect if that third switch was simply joining the two strappers.

? If so, I thought what I wrote 'earlier' was fairly clear (and very similar to what I recently wrote), namely:

From the behaviour he's describing,it sounds as if the intermediate switch is simply joining the strappers when in the 'on' position.

Was it perhaps my reference to 'the on position' which confused you? I meant when the 'intermediate switch' was in the position that made the lights come on, regardless of other switch positions.

Kind Regards, John.

 

[EFLImpudence]

Is that a reference to my recent statement:

Yes.

...and as I said early in the thread, the behaviour the OP was seeing was what one would expect if that third switch was simply joining the two strappers?

Yes, but that's what intermediate switches always do so I didn't realise you meant joining 'on the same side' in order to override the circuit.

If so, I thought what I wrote 'earlier' was fairly clear (and very similar to what I recently wrote), namely:
From the behaviour he's describing,it sounds as if the intermediate switch is simply joining the strappers when in the 'on' position.

Was it perhaps my reference to 'the on position' which confused you?

Not really - intermediate switches 'join the strappers' when in the on and off positions.

It is evident now you mention -

I meant when the 'intermediate switch' was in the position that made the lights come on, regardless of other switch positions.

but, as Adrian wrote, a one way switch could do that.

 

[JohnW2]

...and as I said early in the thread, the behaviour the OP was seeing was what one would expect if that third switch was simply joining the two strappers?

Yes, but that's what intermediate switches always do so I didn't realise you meant joining 'on the same side' in order to override the circuit.

Not in the sense that I meant - sorry if I wasn't clear enough. I was referring to the situation of a standard '2-way' switching circuit, with unbroken strappers joining the two switches, with a 'third switch' simply joining those two (unbroken) strappers together.

Not really - intermediate switches 'join the strappers' when in the on and off positions.

As above, not in the sense of 'joining' that I meant. Again, sorry if I was not clear enough for you.

...but, as Adrian wrote, a one way switch could do that.

Exactly and, as I said, like him I have seen that done deliberately. However, we seem to be being told that the same can happen with an incorrectly-wired intermediate switch, since that is the functionalityvthe OP is experiencing (I need to scribble on some fag packets to see if that's correct). If that's not the case, then your 'remedy' may not work, since the implication would be that something else may (also) be wrong.

Kind Regards, John

 

[333rocky333]

Leave the light alone for now
an intermediate should switch "X" or "II" across the strappers sounds like yours is connected "X" and "=" thus linking across the pair , instead of straight through.

i got what you meant john

 

[JohnW2]

i got what you meant john

You did indeed - and hopefully at least some others may have 'got it' ás well However, I admit that it can be very easy (for me or anyone else) to misunderstand via this medium, so I'd never criticise anyone for that!

Kind Regards, John

 

[EFLImpudence]

 

[bobMuk]

Thanks for all the help guys - I rotated the wiring (by swapping 2 wires as EFLI suggested) and suddenly we're all good.

Lovely job! Thanks again,
Bob

 

[JohnW2]

Thanks for all the help guys - I rotated the wiring (by swapping 2 wires as EFLI suggested) and suddenly we're all good.

Great. Glad you've 'sorted' it.

Kind Regards, John