2 way lights again (Oh and why I don't like domestics)

[SUNRAY]

"Got a little 2 way switch job for you Sunray"
"More rubbish?"
"Customer says they changed a switch and now it doesn't work."

This is just how I found it:

"I took the broken switch off and forgot how it was connected so I went on-line and couldn't find the same numbers of cables."

The hall light was on. I saw a single choc block on the radiator shelf and he confirmed it was in there. Initially it seemed like an obvious repair until he went on, "If you flick this switch the lights in the extension go off, Don't flick the other switch or the trip goes."

The other switch:

The other switch:

 

[SUNRAY]

I was able to trace the harmonised cable:

 

[bernardgreen]

I wonder if the two way began life in this way

Do NOT use this method.

While in theory it appears to work ( and it does with old toggle type switches ) with modern switches transient Live to Neutral arcs can be created as the switch contacts change state. Repeated arcs will damage the switch and/or trip the MCB.

 

[AndyPRK]

Thought it was only Americans that used that method.

House looks far too modern for that method.

Did you fix it then? Asking for help? Or a quiz?

 

[AndyPRK]

You just take the black and blue out the switch and into the chock block. Don’t you?

 

[AndyPRK]

Did he say he didn’t touch the other switch ? And why is it 3gang?

 

[ban-all-sheds]

View attachment 152839

Is that an intermediate, or a 2-way with a loop terminal?

 

[SUNRAY]

I wonder if the two way began life in this way

View attachment 152845

Do NOT use this method.

While in theory it appears to work ( and it does with old toggle type switches ) with modern switches transient Live to Neutral arcs can be created as the switch contacts change state. Repeated arcs will damage the switch and/or trip the MCB.

Spot on, I suspect that is what caused the switch to fail, and this replacement (not new) had already failed one contact but it was wired wrong and directly across the mains.

 

[SUNRAY]

Is that an intermediate, or a 2-way with a loop terminal?

Intermediate being used as a 2 way.

 

[SUNRAY]

Thought it was only Americans that used that method.

House looks far too modern for that method.

Did you fix it then? Asking for help? Or a quiz?

Half hearted quiz, its fixed but staying wired as that method as they didn't want any more cables run

Did he say he didn’t touch the other switch ?

Correct he did not touch the other switch but extension (harmonised) added fairly recently.

And why is it 3gang?

Don't know, been like it since 1996.

 

[SUNRAY]

After this I moved the single red to the other terminal (Customers insistence) to prove operation as this replacement switch is faulty. Then fitted brown & blue sleeve all over the place.

I checked another 2 way system in the property which is wired the same and untouched since they moved in 1996.