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Confusing bathroom lights and fan wiring

Discuss Confusing bathroom lights and fan wiring in the DIY Electrical Advice area at ElectriciansForums.net

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
 
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?
 
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.
Extract fan with two lights DP switching and shaver.jpg
 
@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 - 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 .
 
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?
 
Richard has interpreted exactly on what I was saying in my post as said without on-site verification cannot be 100%.
 
As long as all are on the same circuit and you haven't got the neutrals interconnected between two lighting circuits.
 
If you get somebody to just swap that double pole switch for a 2 gang switch, putting one pole on each switch, you should end up with a switch for the lights (which can be left on) and a switch for the fan. (This is assuming 1 pole is the lights and the other is the fan, but would be a good place to start)
 
Some more information here.
  • This wiring is original. The flat was built by Taylor Wimpy in 2013.
  • The fan appears to be a CMEV.4E. Apparently, it's three speed, house-wide extractor designed to be always on, on a near silent low setting, with the medium and high speeds designed to be manually switched. Product information, including wiring diagrams, are here.
  • I can't confirm if it is always on - either it's too quiet for me to tell, or it's not. As it only extracts from the bathroom and kitchen, I'm not sure it needs to be.
Kitchen Switch (there's a grey wire not connected to anything tucked in the box:
https://i.Upload the image directly to the thread.com/ay0nUhI.jpg

https://i.Upload the image directly to the thread.com/jw9EG0e.jpg

Isolator:

https://i.Upload the image directly to the thread.com/6W2HTOz.jpg

https://i.Upload the image directly to the thread.com/aiiG61C.jpg

https://i.Upload the image directly to the thread.com/2M1sM83.jpg


Wanted to add this to the first post to keep all the info in one place, but seems I can't edit the post, so sorry it's a bit everywhere now.

So this seems even more complicated than I thought. Am I not better off just removing live cables from the Bathroom Switch until the lights won't turn on, then putting them in a separate switch, and leaving the fan wiring as is?
 
To answer your last question... no. Random removal of conductors is never a good plan.

Can you not isolate it fully, and work out the wiring by appropriate dead testing? Draw a diagram and then work out what needs to change at the bathroom end to achieve the desired result.
 
The gray needs to be made safe at both ends as not needed.
Fan isolator needs to be changed to a switched fused spur fused to 3A.
Is the bathroom and kitchen lights on the same circuit as the fan?
 
The gray needs to be made safe at both ends as not needed.
Fan isolator needs to be changed to a switched fused spur fused to 3A.
Is the bathroom and kitchen lights on the same circuit as the fan?
Needs to be that big to get all the wires in
The knock out at the top of Appleby fast fix boxes is big enough to get more cables than is there.
 
So the supply is looped at the fan isolator and the bathroom switch, perhaps. Each switch that operates the fan is paralleled with three core cable (but the grey is used for neutral at the bathroom switch but only seems to go (possibly) to a connector block at the isolator).
I think the three core must have been the original plan but things changed (not for the better). I hope there is not a brown wire in the middle top terminal of the fan isolator. The fan isolator does not isolate the switched line but does isolate the permanent line and neutral, probably.
The fan is only switched from trickle to max boost.
9dB would be very hard to hear on trickle.
The fan switch could be separated out assuming my guesses are correct.
A somewhat confusing arrangement of wiring for a simple system, but perhaps logical when you are on site. Certainly not ideal; no need for a 3A fuse if fed from 6A lighting.
Bit of a guess at the wiring even though I cannot see all the connections in the TP isolator.
Extract fan with two lights DP switching and shaver 2.jpg
 
I did this to the bathroom light switch:

https://i.Upload the image directly to the thread.com/raVHZik.jpg

This stopped the fan boost turning on with the bathroom light.

Is there any reason why I shouldn't simply separate the poles with a 2-gang light switch like this?
 
I did this to the bathroom light switch:

https://i.Upload the image directly to the thread.com/raVHZik.jpg

This stopped the fan boost turning on with the bathroom light.

Is there any reason why I shouldn't simply separate the poles with a 2-gang light switch like this?
Is there a reason why there is 2 cpc's in the same piece of sleeving and why there is so much copper on show? That wiring needs shortening also.
 
I tink u mint bud speeling! :D
You've been on the spelling patrol so thought I'd get some payback :p
Not a problem Mate, no spelling mistake though was there just the wrong word used, I'll be watching you from now on, so be ware and be careful, OK:tongue::smilingimp::rage: And above all live long and prosper.
 
I did this to the bathroom light switch:
This stopped the fan boost turning on with the bathroom light.
Is there any reason why I shouldn't simply separate the poles with a 2-gang light switch like this?
Replacing the DP switch with a 2 gang 2 way switch is likely to be OK, but from afar we cannot tell if there may be other problems this may cause in the wiring. It does seem as if the live supply for the fan is not fed from either of the switches, but possibly from the fan isolator.
However to be able to categorically state it would be OK would not be possible at forum level.
 

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