Confusing bathroom lights and fan wiring

[Baddegg]

I think I would shed a real tear if I opened that up.......

 

[SparkyChick]

I think the key is the fact there (unless I've misinterpreted the OP) is one fan (ducted to process the kitchen and bathroom) and it's switched instantly from both locations.

But regardless, it looks like a right bodge.

 

[Toneyz]

This is what I think (and I apologise if it is repeating what Westward and SparkyChick have posted as I think they are thinking the same)
There is a lighting circuit feeding in and out of the switch.
One of the cables is for the shaver socket
The other twin&E to the bathroom lights this switches through N pole
FAN
There is an AHU, fan unit etc as described a 3 core and earth would of been taken to the bathroom and kitchen and is being used as a linked switch in both locations
A suggestion would be a 2g grid switch with one switch for the light and an engraved fan switch.
I don't think that the neutral should be in with the lighting neutrals.
If the OP does not want a switch for the bathroom it would be a case of the bathroom switch wire being put with the lighting circuit permanent live.
This is only a guess from posts and advise an electrician be sought to test and confirm.

 

[robd]

Just needs someone decent to look at it and suss it out doesn't look that drastic

 

[stringsonfire]

Thinking about it, the ideal way to have this would be a separate bathroom fan switch that works like a local isolator (be it in a separate box or grid switch) so that:

https://i.Upload the image directly to the thread.com/rBYIbaC.png

That way, I can use the Fan switch to turn the fan on and off, keeping my Hue lights always on, and when I eventually move out, the next people can leave the fan switch always on, and just control it with the light switch like they'd expect.

So anyone here in Hertfordshire?

 

[mhar]

but when did OP mention a SFCU?

Isn't that exactly the point of the question?
The op and his electrician have not recognised the wiring method, they have looked at a double pole switch and been baffled by it. This is a method that I first came across 10 years or so ago and was equally baffled but is a method I still occasionally use (admittedly usually with a dp mk logic ceiling pull switch). If I removed a switchplate and saw the wiring as per the photo my first thoughts wouldn't be wtf but I would be thinking the installer has cleverly seperated the fusing of both the fan's line conductors from the light switch and provided isolation of all live conductors to the fan (without affecting the bathroom light) for the cost of a couple of metres of 1mm t & e and a wago plus having avoided one of those beautiful fan isolator switches

 

[mhar]

 

[mhar]

The picture in the op is exactly the same as in my diagram above, hence my reply

 

[westward10]

The picture in the op is exactly the same as in my diagram above, hence my reply

I see what you are getting at now.

 

[SparkyChick]

Except that's not how it's wired.

From the OP, there are two switches that control the fan as the fan serves both the kitchen and the bathroom. The DP switch is there to separate the bathroom light switching from the fan switching so the bathroom light doesn't come on when the fan is turned on from the kitchen.

 

[Octopus]

I think the op needs some local competent assistance ....

 

[mhar]

Except that's not how it's wired.

From the OP, there are two switches that control the fan as the fan serves both the kitchen and the bathroom. The DP switch is there to separate the bathroom light switching from the fan switching so the bathroom light doesn't come on when the fan is turned on from the kitchen.

Ok, a variation on a theme. In my drawing (dare I call it an artistic masterpiece?)the bathroom light will not be on unless it is switched by the dp switch regardless of whether a switch in the kitchen is operating the fan as well. There is no back feed from the fan because of the use of the double pole switch

 

[Marcus Vaughan]

It isn't that unconventional! It is just a method of wiring using an sfcu to give isolation to all 3 live fan conductors whilst not isolating the bathroom light (so that you can see what you are doing!). Avoids having a triple pole isolator and is a neat way od doing things

But the neutral cannot be isolated?

 

[Toneyz]

But the neutral cannot be isolated?

Isolating what the fan?

 

[Marcus Vaughan]

Isolating what the fan?

Forget that, talking cross purposes, I posted the above by looking at the photo - not the drawing.

 

[Richard Burns]

I would think that if the electrician was having problems that the cables present at the fan may be the ones initially planned and the switching was then adapted to use the previously installed cables.
It sounds like a fairly logical original plan to use a double pole switch in the bathroom and kitchen to allow the fan to be switched on in either location without also operating the light that was not local to the switch.
However the actual wiring plan would need to be assessed with testing and inspection of all switches.
I can use the photographed cables to get a timed fan to work using twin and earth and 3 core but cannot work out how to avoid the timer function. Ah yes use a double pole switch for the fan and wago the permanent line and loop switched line/line in the fan.
A possible layout? obviously subject to verification.

 

[SparkyChick]

@Richard Burns - What software do you use to produce your diagrams? You always seem to be able to knock them up in double quick time and they are usually pretty darn good.

 

[Richard Burns]

@Richard Burns - What software do you use to produce your diagrams? You always seem to be able to knock them up in double quick time and they are usually pretty darn good.

Very kind of you, thank you. I do not usually do diagrams for work (because I am lazy) so I just use powerpoint for the forum diagrams.
I already have various accessories drawn out from previous diagrams and use connectors for the cables. Probably slower than a dedicated program but just one with which I am familiar .

 

[SparkyChick]

Very kind of you, thank you. I do not usually do diagrams for work (because I am lazy) so I just use powerpoint for the forum diagrams.
I already have various accessories drawn out from previous diagrams and use connectors for the cables. Probably slower than a dedicated program but just one with which I am familiar .

Sometimes the dedicated stuff does things that just get in the way and actually make it harder to draw a nice diagram. I used to use SmartDraw alot, then they added all sorts of features that 'made it easier'... yeah right... easier if you want a diagram laid out on this perfect grid.. anything else became a night mare.

I'm going to be cheeky and ask... any thoughts on possibly sharing say a PowerPoint with the common symbols in?

 

[Toneyz]

Richard has interpreted exactly on what I was saying in my post as said without on-site verification cannot be 100%.