Shower extractor, again.

[BMcN]

I am wanting to run my shower fan extractor without having to put in a separate pull cord. So presuming it requires a live and sw live for the timer and I want it to come on with the shower and off when the shower goes off, what is the best way to do this?

I have saw the solutions where the fan comes on with the lights or via a separate pull cord but neither of these are exactly what I am looking for.

Thanks.

 

[holmslaw]

..

 

[BMcN]

Switching the fan off when the shower stops will not adequately clear the moist air.

You can get fans with built in humidistats that will run as long as there is moist air.

How about if I take the live feed from the live side of the shower isolator, take the switched live from the switch side of the isolator, both with 10mm or 6mm cable into a fused isolator (say 3 or 6A fuse) and then on from there with 1.5mm to the extractor.

This would give everything on the 40A side 10mm cable and then fused to 3A, allow everything to be isolated and allow the fan to run after the shower has been turned off.

 

[holmslaw]

..

 

[BMcN]

Any other opinions on what I suggested?

 

[Steve]

Any other opinions on what I suggested?

You'll struggle to get all those 10mm² cores into a standard shower isolator. IMO they are already a terrible design, without you adding to the madness.

You aren't supposed to power any other appliances from a shower circuit (or other dedicated circuit).

 

[plugwash]

How about if I take the live feed from the live side of the shower isolator, take the switched live from the switch side of the isolator, both with 10mm or 6mm cable into a fused isolator (say 3 or 6A fuse) and then on from there with 1.5mm to the extractor.

Bad idea, this would make the fan bridge over the isolator which could create a dangerous situation when the isolator is off. You would also have to fuse both the permanant live and switched live feeed.

If you can live without a timer (shouldn't be too big a deal just leave the shower isolator on for 10 minuites or so after your shower) then you could take a spur from the cable on the load side of the isolator with appropriate protection (I would probablly use a double pole MCB in a two module din rail box, the terminals of a MCB will easilly take 2x10mm).

If you really want to have a timer then you will need to use a contactor and protect the feed side of the contactor BAS wrote a post giving details of how he did this some time ago but either admin are deleting old posts or the search facility sucks because I can't find it now.

 

[mbbalone]

I did exactly what you wanted to do. I took a feed off the shower and put it through a fused outlet to protect the low voltage fan and it was brilliant, the shower came on and off when the shower power cord was pulled. Well it was brilliant until the building inspector saw it and then made me rip it all out. There is PIR systems you can use but the problem is linked with moisture ingress to electrical bits and the only thing he would let me do was take a feed off the lights to a fused outlet and it had to be on the ouside of the bathroom. Dont forget you also need to earth bond all this work.

 

[ban-all-sheds]

Your idea does'nt sound very good, normally a bathroom fan is taken off of the lighting circuit.

Yes, but functionally that's not a good design.

How about if I take the live feed from the live side of the shower isolator, take the switched live from the switch side of the isolator, both with 10mm or 6mm cable into a fused isolator (say 3 or 6A fuse) and then on from there with 1.5mm to the extractor.

I don't think he did...

BAS wrote a post giving details of how he did this some time ago but either admin are deleting old posts or the search facility sucks because I can't find it now.

//www.diynot.com/forums/viewtopic.php?t=20386



Plan B: use a timer fan, and trigger it with a flowswitch in the water supply to the shower.

Well it was brilliant until the building inspector saw it and then made me rip it all out.

Did he really?

What reason did he give? What did you do wrong?

There is PIR systems you can use but the problem is linked with moisture ingress to electrical bits

I'm sure it must be possible to get PIRs with a suitable IP rating. I've heard that some are even OK to use outside in the wind amd the rain...

and the only thing he would let me do was take a feed off the lights to a fused outlet and it had to be on the ouside of the bathroom.

Did you ask him why he thought that was the only way to do it?

Dont forget you also need to earth bond all this work.

Not necessarily....

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[mbbalone]

mbbalone wrote:
Well it was brilliant until the building inspector saw it and then made me rip it all out.

Did he really?

What reason did he give? What did you do wrong?


Quote:
There is PIR systems you can use but the problem is linked with moisture ingress to electrical bits

I'm sure it must be possible to get PIRs with a suitable IP rating. I've heard that some are even OK to use outside in the wind amd the rain...


Quote:
and the only thing he would let me do was take a feed off the lights to a fused outlet and it had to be on the ouside of the bathroom.

Did you ask him why he thought that was the only way to do it?

So in answer to all the above. Knowing it was notifiable and enjoying electrics I did notify but not before I'd put the new bathroom in. I am still working under 16th edition.

Inspector made me take it out because I put a fused spur up high in the bathroom fed from the live of the pull switch for the shower with 2.5mm cable. Three faults, miss matched cables 10mm feeding 2.5mm, no IP rating on the fused spur cover (there is no such thing I tried) and lack of earth bonding.

As for PIR there are PIRs you can get but by this point I was a bit fed up and went for the "easy option"

 

[ban-all-sheds]

So in answer to all the above. Knowing it was notifiable

It's a shame you went ahead without knowing what you were doing.

I am still working under 16th edition.

No you aren't...

Inspector made me take it out because I put a fused spur up high in the bathroom fed from the live of the pull switch for the shower with 2.5mm cable. Three faults, miss matched cables 10mm feeding 2.5mm, no IP rating on the fused spur cover (there is no such thing I tried) and lack of earth bonding.

And three contraventions of the 16th...