Light switch wiring help

[ash_scotland88]

Looking for help how to "decipher" this wiring.

 

https://ibb.co/9v3q15V

 

Left to right goes:

Outside (front flood)

Above front door

Downstairs hall

Landing

Its a 1switch and 3gang switch side by side.

 

The old CU had outside on its own separate fuse (paired with understairs cupboard) and the other lights on their own fuse, with other lighting too.

New CU have the current lot in one fuse, along with some other lighting. And there's a 6amp RCD waiting for new path lighting.

 

My thought was I should be opening the light switches and outside would have its own live feed and the other three switches their own live- because they were separate circuits from CU. But it appears to be live linked with the other switches, am I right in my understanding? Surely this would suggest original CU markings was wrong and outside is not on its own circuit?

 

My plan was to take the wiring for outside at the CU and move it onto the 6amp RCD. Then swap the 1gang and 3gang to 2x 2gang. This would allow me to put the front door in with the 6amp RCD and "tap into" for new path lighting allowing current front door switch to control path and keep the flood on a separate switch.

 

The light switches has completely thrown me.

[ProDave]

If the image was not so big I could paste it here.  9.1MB it does not need to be that high resolution.

 

There was probably a reason the two separate circuits have been put as one now, perhaps they were always linked?  Or more likely a borrowed neutral situation.

 

 

[Temp]

[ash_scotland88]

Sorry about size. Didn't even think/used to screens auto scaling.

 

Are others coming to the same conclusion as me, that they appear to be linked at the switches?

Looking at the picture again is the switch on the right by itself?

[ash_scotland88]

So bought a 2gang switch to replace the single.

Removed the link cable that goes from single switch to the three gang.

Moved the front door over to the two gang and reused the link cable to provide power. 2gang is now front door and exterior flood.

 

Landing appeared to have its own live feed so moved over the secondary link (old front door to hall) so it is now landing to hall.

 

Everything appears to be working as should be, so to me this is suggestive of two separate live feeds to the two switches.

 

All I can think of is at some point either old CU was marked wrong or come some switch rewiring they decided to make front door and hall come off exterior.

 

Any-one want to way in on theories? Or tell me what I've done is wrong...

 

 

(If I can find a free non sign up image hosting I'll link a picture)

[ProDave]

The usual reason for joining 2 apparently separate lighting circuits is when you find a borrowed neutral.  It is found most on landing lights where the light may have got it's L from the downstairs light circuit and N from the upstairs light circuit.

 

If you reduce the image to a smaller size (in Kb not necessarily pixels) you can upload it to the forum.  I find the latest version of PhotoScape is good at producing very efficient size photos.

[ash_scotland88]

Link again incase it's still too big. But my phone automatically resizes to fit the screen, but if your worried about data allowance hopefully this is less.

https://postimg.cc/JDhTPxMJ

 

Quick reading about shared neutral suggests that if that was the case the MCB and/or RCD would trip if they are wired under different ones. But this switch and upstairs (where other landing switch is) are under the same MCB and RCD, so that tripping won't happen - as the quick suggestive test.

The fact that they are now wired under the same then the safety issue of thinking you've flipped the one switch to work on a light and only finding out otherwise when you get a shock won't happen in this instance. If I'm understanding correctly.

 

Both of the switched have 2 neutrals going to (or is it coming from?) them, which I think I read is also suggestive of a not shared neutral, but I can't re-find this information.

[Mr Punter]

I don't believe what is labelled on a CU.  I once spurred off a kitchen socket having taken removed the ground and kitchen fuses.  It turned out the socket was fed from upstairs.  Luckily it only cost me the time to rewire the fuse but I have been more careful since.

[ProDave]

3 minutes ago, Mr Punter said:

I don't believe what is labelled on a CU. 

I learned that lesson in an industrial unit.  I was there to change the hand dryer in the gents toilet.  So I switch off the MCB labelled "Gents toilet" and heard a groan from the end of the corridor where I had just turned off an office full of people using computers.

[ash_scotland88]

37 minutes ago, ProDave said:

I learned that lesson in an industrial unit.  I was there to change the hand dryer in the gents toilet.  So I switch off the MCB labelled "Gents toilet" and heard a groan from the end of the corridor where I had just turned off an office full of people using computers.

We joke about tripping off catering unit supplies at the rubber box, easy way to get chatting to them for hopes of free food on events.

I proposed with the advent of smart fuses we need a phone app to do it remotely.

[Temp]

3 hours ago, ash_scotland88 said:

Link again incase it's still too big. But my phone automatically resizes to fit the screen, but if your worried about data allowance hopefully this is less.

https://postimg.cc/JDhTPxMJ

 

This looks different to the earlier photo. Two switches now on the left?

 

Is there a red wire from one face plate to the other? If so it still looks like Permanant live on Red. Switched lives to the lights on yellow and Blue.

 

[ash_scotland88]

@Temp there are nos two switches on the left. The furthest left of the three switches is now unused (middle of the five).

There is now no longer a red wire connecting the two face plates. And don't worry I trimmed down the red wire on the left. Everything appears to be working as should.