Three red wires going into ceiling light fitting, no black!

[SenileGit]

Hi, I have fitted two inline extractor fans in my loft, which I am going to use during summer nights, one fan pulls cold air from outside into the bedroom, the other blows warm air from in the bedroom outside. This is the theory, I haven't come across anybody ever doing this before, but I think it will work well to cool the room down at night. (I can't leave the window open because I live in a bungalow and don't fancy waking up to a burglar in my room, and I've tried having a table fan on the windowsill for a few hours after it gets dark, trying to blow cold air into the room, but on really hot nights it doesn't make much difference, and I end up having the window closed and the fan blowing over the bed, which is really noisy and keeps me awake - it's either turn off the fan and be hot but quiet, or turn it on and be cooler but kept awake by the noise.)
I can't work out how to take power from the lighting circuit (which I presume is the safest way to get power to the two extractor fans). My bungalow was built in the 1950s, and there are three red wires coming from the loft into the light fitting, as shown below.

I presume that the red wire '3' is coming from the switch, because the other two wires, '1' and '2' are screwed into the same block. I know that either '1' or '2' is a 'Loop Out' to the bedroom next door, because when I disconnected all the cables from the fitting and pulled them up into the loft, in order to temporarily connect them to the extractor fan switch I have installed, using Wago connectors, when only '1' or '2' was connected to one of the Wago connectors, and thence to the neutral wire from my switch, the other bedroom's ceiling light didn't work when I turned the power back on. When I plugged both '1' and '2' into the same Wago connector, along with the neutral wire from the extractor fan switch, the other bedroom's ceiling light DID work. I have tried every combination possible of the three cables, connected to the live and neutral cables coming from the ceiling switch I have installed, and I can only get the extractor fans to work if the wall light switch is turned on in the bedroom - so at least I know that I have wired up the extractor fans correctly, and that they are working fine. It appears that none of these three red cables are neutral - is this possible? The red cables are all sheathed in grey cable up in the loft. They are all completely separate wires. (I am running 1mm or 1.5mm (I can't remember what size it is, but it isn't 2.5mm) Twin and Earth for the extractor fans, I presume this is the correct way to do things.)

I then looked behind the switch in the bedroom, and wasn't surprised to see that there are three red cables, sheathed in grey cable, going to the top of the switch, and one red cable going to the bottom of the switch.

Is anybody familiar with this sort of wiring? I can't understand how the electrician who fitted the cables would know which was which! Should I be looking elsewhere in my loft for a neutral cable - and is it likely to be one of these wretched red cables, instead of a black or blue one? I presume that one of the red cables in the switch (either the group of 3 at the top, or the lower single one) must be neutral? Otherwise the light wouldn't work, surely.

I have a very good electrician who I will contact tomorrow if nobody can work out what is going on here, I'm sure he can fix it for me, but if it's just a matter of finding a neutral cable in the loft, I'm happy to try myself! Many thanks in advance if anybody can help me.

 

[Johnmdc]

I would say that 1 and 2 are the neutral in and out (these should have been black) and 3 is the switched live, which will be the wire on it's own at the bottom of the light switch.
If you want the fan to work independent of the light then you will need to find a permanent live feed.
You will have to connect onto one of the three wires that are going down to the switch, in the loft. The neutral can be picked up from the terminal that 1 and 2 are connected to in the ceiling rose.
How are you planning to turn the fans on and off though?
Also there doesn't appear to be any earth wires so your fans must be double insulated (not metal).

 

[JohnW2]

Also there doesn't appear to be any earth wires so your fans must be double insulated (not metal).

Certainly no connected 'earth wires', and quite apart from the fan, that would result in an un-earthed metal back box and associated faceplate screws.

However, it looks as if 'earth wires' may actually be there, but currently 'cut off' pretty short ...

Kind Regards, John

 

[winston1]

If 3 is a switched live and 1 & 2 are neutrals the brown and blue to the light are the wrong way round.

There will not be a neutral to the switch. It only needs a permanent live and switched live.

You do not have enough knowledge to do this job. Let your good electrician do it.

 

[plugwash]

There will not be a neutral to the switch. It only needs a permanent live and switched live.

One would hope so, but given the level of ****ery visible in this installation, I don't think switched neutrals can be ruled out.

 

[sparkwright]

Certainly no connected 'earth wires', and quite apart from the fan, that would result in an un-earthed metal back box and associated faceplate screws.

However, it looks as if 'earth wires' may actually be there, but currently 'cut off' pretty short ...

View attachment 270929

Kind Regards, John

If it was an earth wire, it would be a tinned copper (ie silver looking) colour, like the red wire.



I wondered if that was the length of cotton they used to like to put in cable years ago.

 

[JohnW2]

If it was an earth wire, it would be a tinned copper (ie silver looking) colour, like the red wire.

Maybe. However, although I may have dreamed this, I thought I had seen some cables with red and black being 'stranded and tinned', but the CPC just bare copper?

I wondered if that was the length of cotton they used to like to put in cable years ago.

Again 'maybe' - but it would be a rather odd colour for such a bit of common, wouldn't it? It's obviously not clear from the piccie, but it dose look very 'copper coloured'?

Kind Regards, John

 

[sparkwright]

Not sure what colour to expect the 'cotton' to be - have noticed the cotton can be a stripey yellow and black, can't remember the other colours (oddly enough).

 

[JohnW2]

Not sure what colour to expect the 'cotton' to be - have noticed the cotton can be a stripey yellow and black, can't remember the other colours (oddly enough).

I can't remember, either, but 'copper coloured' struck me as a little surprising/coincidental.

Kind Regards, John

 

[SenileGit]

Thank you all for your help, especially Johnmdc, I traced the three wires in the loft that go to the switch, I used a 'live cable' tester to make sure I was choosing one of the three live ones, as the fourth one that goes to the bottom of the switch was presumably neutral, then I cut the cable and attached the red cable of some Twin and Earth cable to the two halves of the cable using Wago connectors and another Wago box, then ran the Twin and Earth to the cable that I had attached to the ceiling switch, and everything works fine.
The little bits of 'copper' cable that JohnW2 saw in the photo of the wall switch are in fact some kind of copper infused thread (as sparkwright surmised above) that are inside the red cable when you strip it - they are literally pieces of thread - were they supposed to tell you the difference between one red cable and another - i.e. presumably at the time (1950s when the bungalow was built) they sold plain red cables in grey sheathing, and red cables with the copper infused thread, so you could see which was which? I have absolutely no idea.

I used Envirovent SILMV160/100mm Compact Inline Fans, all plastic, and a brilliant design - the body of the fan can easily be removed completely from the frame that it sits in, so I was able to mount the frame, put on the ducting from the soffit, then easily wire the fan itself in a part of the loft where there was more room, and then you just push the fan into the fan frame and push together two releasable clips that encircle it at either end. I chose the slowest of the two speed settings, and the fans themselves are extremely quiet - but the insulated ducting causes a lot of turbulence (plus I have a 180 degree bend in it to reach back nearer the wall of the bedroom, where I wanted the ceiling grilles to be) which doesn't help. Although the other ducting, which is conventional Toolstation ducting, on the outgoing fan, also has a 180 degree bend in it, but it makes hardly any noise.

So this is what I have done (pictures below) - everything is working fine, but I will get my electrician to have a look at it next week when he comes round for another job.


Outlet fan (shown here before I put the ducting from the bedroom into it)

Inlet fan (ditto with the ducting, which was a nightmare to put on due to the limited space, and it was insulated ducting as it was all I had, and it's very difficult to get on).

I ran the cables up the rafters to keep everything away from the loft floor as much as possible.

All connections done with Wago 221s (I think, from memory) and Wago boxes, this is the two fans being joined in parallel, then going to the ceiling switch via the left hand cable.)

Ceiling switch - those are two screw holes I initially made while trying to screw the switch box into a flat piece of wood in the loft above the ceiling board, then I decided to screw into the joist (I should have done that in the beginning). I wanted one with a light on so that I can see if the fan is on or off just by looking up, as I wear earplugs in bed to help me get to sleep.

Inlet fan grille from Ebay, this is at the far end of the room (away from the head of the bed) because it is the one that makes noise, the other one (not pictured) is about eight feet away, to suck out hot air from the top of the room.

Here is the 'dust catcher' I made to prevent the plasterboard going all over the bedroom when I drilled the two 100mm holes! It worked perfectly, saved me hours of cleaning up mess - when I cut my first hole in a ceiling in my bathroom, I had a friend hold a vacuum cleaner nozzle up where I was cutting the hole (without a 'dust catcher') and the mess was horrendous, the vacuum made no difference at all. With my 'dust catcher', I just held it against the ceiling with one hand, while drilling with the other, and only the tiniest amount of dust escaped, all the rest just fell into the 'dust catcher'. I presume you can buy these things, or have I invented something new?

I used some Lidl draught excluder to form a soft edge to the top of the ice cream tub, you normally tear it down the line in the middle to make two thinner lengths of draught excluder, so I just folded it down the middle, on the inside and outside of the tub, worked perfectly!

Shown here with the hole cutter inserted:

I am very pleased with the result, I'll get my electrician to look at everything before I use it again, I've only turned it on and made sure the fans are both working, and all the lights are working okay, but I won't push my luck and will wait for him to check it all. Thank you all for your help!

 

[winston1]

as the fourth one that goes to the bottom of the switch was presumably neutral,

You assume wrong. The switch does not have a neutral.

 

[JohnW2]

You assume wrong. The switch does not have a neutral.

True, but it would be more useful if you were to suggest what it probably is, rather than merely indicating what it isn't. There's nothing wrong with 'criticism', so long as it is 'constructive'.

 

[winston1]

It is a switched live probably.

 

[Risteard]

It is a switched live probably.

Neutral is live.

I presume you meant "line" (phase).

 

[bernardgreen]

Neutral is live.

I presume you meant "line" (phase).

While what you say is strictly speaking true using "Line" for the wires that are 230 V above Earth potential is confusing for the average DIY reader.

Like wise calling the Neutral wire Live is also confusing for the average DIY reader.