Two gang switch, halogen downlight and photos

[SJRSJR]

Can you help me understand what might be going on here please? I don't plan to do the work (unless you say it's easy). We're re-decorating the hall and have this switch by the front door.
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The left switch (on the right as you look at the photo) controls an outside light. The other switch appears to do nothing and we've lived here a year!. I am guessing from the cable that it was once part of a two way hall/landing set up but we currently have a separate switches for all that.

Having removed a piece of plasterboard over the doorway we have found this junction box. The cable coming into the left comes from the switch, the cable on the right goes to the outside light. I can't be sure where the other two go. It definitely doesn't go to the hall/landing switches as they have different coloured cable.
View media item 65125 .

When we replace the plasterboard we would like to put in a halogen ceiling downlight. Can we run it from the junction box and use the 'unused' switch? We have a spare single transformer-free halogen light but no instructions. How would it be wired?
View media item 65129Thanks for any info.

 

[wingcoax]

pic of the inside of junction box would be helpful.

 

[SJRSJR]

Here you go. Thanks
View media item 65130

 

[plugwash]

The left switch (on the right as you look at the photo) controls an outside light. The other switch appears to do nothing and we've lived here a year!. I am guessing from the cable that it was once part of a two way hall/landing set up

There aren't enough wires for either of those switches to have been part of a two way system.

When we replace the plasterboard we would like to put in a halogen ceiling downlight. Can we run it from the junction box and use the 'unused' switch?

Most likely yes. If you want instructions though you will need to take the lid off that junction box and get us a picture of what is going on inside.

We have a spare single transformer-free halogen light but no instructions. How would it be wired?

it looks like there is a black plastic box on the end of the wires from the lampholder. Presumablly the terminals are in there.

 

[SJRSJR]

it looks like there is a black plastic box on the end of the wires from the lampholder. Presumablly the terminals are in there.

Plugwash, the two cables just go to a terminal block. There's nothing marked.

 

[plugwash]

Here you go. Thanks
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It looks to me like both switches originally controlled different aspects of an outside light. Maybe one to switch it on via a PIR and one to switch it on permanently.

It is possible that the outside light has since been replaced by one that only uses a single switch. what is the wiring like at the outside light.

 

[SJRSJR]

This is the outside light - it is currently single switch, no PIR.
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[plugwash]

it looks like there is a black plastic box on the end of the wires from the lampholder. Presumablly the terminals are in there.

Plugwash, the two cables just go to a terminal block. There's nothing marked.

Is the light marked with the "double insulated" symbol (two concentric squares. Assuming it is connect live and neutral to the two wires from the lampholder, leave earth disconnected.

In the junction box connect the live from your new light to the terminal that has the blue from the switch and the red from the outside light. Connect the neutral to the terminal that has one blue and two blacks and connect the earth to the terminal block that has the exsiting earths in it.

This is the outside light - it is currently single switch, no PIR.
View media item 65132

Interesting. It looks to me like there is a second cable leaving that light controlled by your "redundant" switch. If it was my property i'd want to find out what that cable used to feed and make sure that the cable had been terminated safely when it was removed.

 

[JohnW2]

This is the outside light - it is currently single switch, no PIR. <picture>

Is there by any chance a second outside light - or evidence that there may have been one in the past?

Kind Regards, Regards

 

[SJRSJR]

Is the light marked with the "double insulated" symbol (two concentric squares. Assuming it is connect live and neutral to the two wires from the lampholder, leave earth disconnected.

Yes it is. Thanks for that, I understand now.

In the junction box connect the live from your new light to the terminal that has the blue from the switch and the red from the outside light. Connect the neutral to the terminal that has one blue and two blacks and connect the earth to the terminal block that has the exsiting earths in it.

Again, thank you very much.

Interesting. It looks to me like there is a second cable leaving that light controlled by your "redundant" switch. If it was my property i'd want to find out what that cable used to feed and make sure that the cable had been terminated safely when it was removed.

There is a PIR outside light at the back of the house which has never worked and is difficult to access. It makes sense that thy would put both security PIRs on simultaneously so will establish if it's connected before we do anything. If it is connected, can we still proceed with the downlight? Does it mean that the rear PiR will only be on if the downlight is on?

 

[SJRSJR]

Is there by any chance a second outside light - or evidence that there may have been one in the past?

JohnW2 - looks like you're both on the same track. Sherlock Holmes could learn a few things.

 

[plugwash]

Does it mean that the rear PiR will only be on if the downlight is on?

Indeed, assuming you follow the instructions I gave earlier and assuming the feed leaving the front light does indeed go to the rear light that is the result you would get. Whether that is the result you want is up to you (it would seem a strange thing to want though).

Disconnecting the rear light and the cable that feeds it would also be an option. Since it's never worked presumablly you wouldn't miss it.

 

[SJRSJR]

We could leave it there, although the cat might not like a floodlight randomly shining on his activities.

Thanks again, it's great to get a swift outcome to our conundrum.

 

[JohnW2]

There is a PIR outside light at the back of the house which has never worked and is difficult to access. It makes sense that thy would put both security PIRs on simultaneously so will establish if it's connected before we do anything. If it is connected, can we still proceed with the downlight? Does it mean that the rear PiR will only be on if the downlight is on?

From what we've seen and you've told us, I think it very likely that the second switch 'which currently does nothing' controls (or controlled) that second (rear) PIR outside light, and that it has never worked because of a failed lamp/bub or some wiring problem.

If that is true, and if you were to 'reassign' that second switch for your indoor downlight (and therefore disconnect what is currently connected to it), the rear PIR light would obviously never work, even if 'mended'.

However, someone needs to do some testing and detective work to confirm what really is going on. If you don't want the rear outdoor PIR, it could then be safely disconnected. On the other hand, if you did want to get it back into service, another possibility to discuss with your electrician would be controlling both outside lights with one switch, thereby leaving you the 'spare' switch you want!

Kind Regards, John

 

[SJRSJR]

Thanks JohnW2, it would make sense to get it all re-commissioned. Will decide before the plasterboard has to go back up.