Bathroom humidistat fan wiring

[bluejeans]

Hi there,

Probably an easy question for the majority of you out there. I am currently replacing the fan in my bathroom with a humidistat one which requires a permanent live and switched live from the pull cord.

Previously the fan just had a pull cord attached which switched it on and off.

I have installed a double pole FCU outside the bathroom in preparation for the wiring and just wanted confirmation on the arrangment of the wiring.

With the 3A FCU (recommended by manrose) I assume it is better to take the switched live through this too so that the FCU switches the fan off regardless of whether the lights are on or not.

Also is it viable to take just the live wire from the FCU to the pullcord and on to the fan, and just cut the neutral and earth down?

Please see the attached for my interpretation of what the instructions are telling me.

Any advice is much appreciated.

Thanks
James[/img]

 

[Softus]

I have installed a double pole FCU outside the bathroom in preparation for the wiring and just wanted confirmation on the arrangment of the wiring.

I would replace that with a triple-pole switched FCU...

With the 3A FCU (recommended by manrose) I assume it is better to take the switched live through this too so that the FCU switches the fan off regardless of whether the lights are on or not.

...which will allow you to do just that!

Also is it viable to take just the live wire from the FCU to the pullcord and on to the fan, and just cut the neutral and earth down?

No.

Please see the attached for my interpretation of what the instructions are telling me.

I would never do it in the way that the diagram says, because it's:

a) confusing to anyone using the switch (i.e. you have to switch off both the light AND the DP switch to make the fan safe);
b) inconvenient when working on the fan.

If you use a 3P switched FCU then you have a single point of isolation.

 

[bluejeans]

Softus, thanks very much for your reply. It was very helpful.

I understand what you are saying and have replaced the 2pole FCU with a 3Pole FCU fan switch which makes more sense as you say.

I have made up another diagram with your comments in mind and would be grateful if you could cast your eye over it.

Note: I have used the old colour coding for the 3 core wire for clarity in the diagram.

Thanks again.
james

 

[Spark123]

I don't think you can get 3 pole fused connection units?
The last ones I did I used a double accessory box with a 3A fused connection unit powering the light and fan, and a 3 pole isolator just for isolating the fan.
I'm also thinking that altering the wiring in a bathroom is notifiable to your LABC under part P of the building regs.

 

[RF Lighting]

And you must use harmonised coloured wiring

 

[Softus]

I don't think you can get 3 pole fused connection units?

You can't. I wasn't concentrating. Apologies to all concerned.

 

[bluejeans]

I realise that the wiring has to be harmonised, just made it easier to describe in the diagram. But thanks for pointing that out

I also realise that I still need an FCU so at which point would I put this into the diagram?

Im guessing that it would need to only go on the supply to the fan so that if it did blow then the lights would still work.

Any advice on how this would fit into the equation would be greatfully received.

I am just preparing everything for the electrician so that he has to spend less time faffing around installing everything.

Thanks

 

[ban-all-sheds]

I am just preparing everything for the electrician so that he has to spend less time faffing around installing everything.

No - you're "preparing" things in a way that will cause him to spend more time faffing around discarding the dangerous and incompetent stuff you have done before he starts from scratch.

Twice now you have sat down and drawn diagrams which show you think it'll be OK to connect Live & Neutral together, and that somehow fans and lights can work with no Live at all.

You don't have a clue - please leave it all to the electrician.

 

[johnfred1]

I think you should just leave it to the electrician.

 

[ColJack]

is that supposed to be the switch in the center of the diagrams?

if so then "com" is NOT the neutral connction.. it's the terminal that the L1 and L2 connect to when switched on..

so the perm live goes to the "com", switched live from L1, NOTHING in L2.