Can I use this switch?

[Bryan Williams]

Hi,recently moved house,the shower is fed from the combi boiler but it looks like the previous owner had an electric shower before and has left the string pull switch.
It's still live,lights up I've, I've turned it off at the fuse .
The room already getting a bit mouldy ,house was empty for months and I think the ceiling may have been painted to hide previous mould.
I'm wondering if I can use this switch for power to an extractor fan?

I have not had a look in the loft yet at the other side of where the switch is

It's a bungalow so I thought through the ceiling and vented back end of the bungalow.
Is it an option?
Cheers.

 

[123hotchef]

yes it is a option, its probably ratted at high amps on the breaker might be a idea to fit a fused spur or similar in the loft before the extractor fan.
I am no sparkie but I am one will be along shortly to tell you the correct way.

 

[AVI_8]

Mine powers the extractor fan as well as the lights.

 

[skotl]

yes it is a option, its probably ratted at high amps on the breaker might be a idea to fit a fused spur or similar in the loft before the extractor fan.
I am no sparkie but I am one will be along shortly to tell you the correct way.

I'd just switch the "shower" breaker for a B6

 

[tigdlo]

If it's fused appropriately for the extractor it will work if you don't mind turning it on and off yourself.

If you control an extractor from the light circuit you will need a 3 pole isolator and maybe a fused supply depending on the fan and it's installation requirements, which may be less than the 6A supply circuit.

 

[123hotchef]

I'd just switch the "shower" breaker for a B6

I was thinking that also

 

[dobbslc]

Just take a feed off the light in the bathroom. If the light has a permanent feed (ie 2 or 3 twin and earth cables up there) you'll need a bit of 3 core & earth cable, feed that down to a 3 pole fan switch then to the fan. You can then have it on a timer with an adjustable overrun.
You can put the old shower cable into a Wago box and leave it in the roof for future use.

 

[Hotstuff]

As others have already said, it is more commonplace for a bathroom extract fan to be supplied from the local lighting circuit via either a switched fuse spur to isolate both the light and the extract fan or a three pole switch to isolate just the fan L+N+Switched live.

You need to consider the dimensions of your bathroom so it might be wise to install your local isolation outside of the bathroom.

From your photo I can only guess that you plan to mount your extract fan on the ceiling and duct away to a gable end or soffit. If that is the case you will probably need a centrifugal fan or an in-line fan can be a little quieter.

With a ceiling mounted fan you will need to consider how you route the exhaust duct to help prevent condensation running back down to the fan which usually leaves a stain on the ceiling surrounding the fan.

Using insulated ducting helps stop the damp exhaust air compensating.

Please be aware that as this lighting circuits serves points located within the bathroom, it should be protected by a 30mA RCD.
If you do not have 30 mA RCD protection at your consumer unit then you could use a 30mA RCD switched fuse spur to supply the bathroom light and extract fan.

Please also ensure that your equipotential bonding is in place.

Just for your information; these works are considered as notifiable under part P of the building regs.

Good luck

 

[keithski122]

Only problem when connected to a light switch is if you want a shower without the need to put the lights on.
When we had an electric shower I took the fan feed from the isolation swith and the switched timer feed from the switch on the back of the shower unit.Everything was fused and met correct ampage but the electrician that had to sign of our electrics wasn't too happy about it.Told him he could change it all to meet standards so he signed it off to save him the hassle of having to change it all.

 

[brightspark]

Only problem when connected to a light switch is if you want a shower without the need to put the lights on.
When we had an electric shower I took the fan feed from the isolation swith and the switched timer feed from the switch on the back of the shower unit.Everything was fused and met correct ampage but the electrician that had to sign of our electrics wasn't too happy about it.Told him he could change it all to meet standards so he signed it off to save him the hassle of having to change it all.

bigger fool him i wouldnt have. its 100 percent by the book or not at at all

 

[keithski122]

Not by the book but it wroked well and when it was needed and was completely safe. A far better option than the cr**py humidistat fan he fitted to our ensuite.I wanted him to fit water flow switches to operate the fan but he wasn't up for that idea.

 

[Hotstuff]

Not by the book but it wroked well and when it was needed and was completely safe. A far better option than the cr**py humidistat fan he fitted to our ensuite.I wanted him to fit water flow switches to operate the fan but he wasn't up for that idea.

Yeh, bloody electricians….I bet you showed him a thing or two.
Thanks for sharing.

 

[MetalMonkey]

Only problem when connected to a light switch is if you want a shower without the need to put the lights on.
When we had an electric shower I took the fan feed from the isolation swith and the switched timer feed from the switch on the back of the shower unit.Everything was fused and met correct ampage but the electrician that had to sign of our electrics wasn't too happy about it.Told him he could change it all to meet standards so he signed it off to save him the hassle of having to change it all.

I would suggest the better option would have been to take the feed from the supply side of your light switch to the permanent and switched lives of the fan (via an isolator) and interrupt the switched live with a pull cord.
That will give you the ability to control the fan independently of the light.

 

[Pete.]

Wasn't there a youtube vid posted here recently of an electrician who thought he'd isolated a boiler but found it was fed lives from 2 circuits?

 

[dobbslc]

Only problem when connected to a light switch is if you want a shower without the need to put the lights on.
When we had an electric shower I took the fan feed from the isolation swith and the switched timer feed from the switch on the back of the shower unit.Everything was fused and met correct ampage but the electrician that had to sign of our electrics wasn't too happy about it.Told him he could change it all to meet standards so he signed it off to save him the hassle of having to change it all.

Not by the book but it wroked well and when it was needed and was completely safe. A far better option than the cr**py humidistat fan he fitted to our ensuite.I wanted him to fit water flow switches to operate the fan but he wasn't up for that idea.

Wow! You really like making things hard work!
Flow switches to operate a bathroom fan!? That's why I run a mile from domestic work, you never know what's burid under a floor or in the roof space...

 

[Matrixx]

If it's fused appropriately for the extractor it will work if you don't mind turning it on and off yourself.

If you control an extractor from the light circuit you will need a 3 pole isolator and maybe a fused supply depending on the fan and it's installation requirements, which may be less than the 6A supply circuit.

Just to be clear the protection is only there for the cables not the device. the protection must be smaller than the current capacity of the cable.

 

[tigdlo]

Just to be clear the protection is only there for the cables not the device. the protection must be smaller than the current capacity of the cable.

Don't the regs specify equipment must be installed to manufacturers instructions? which often specify a 3A fuse for a bathroom fan.

Extractor fans are a cause of house fires, 182 for 2019/2020. Many are fitted to 10a or 6a circuits without fusing down the feed, it is plausible that a 3A fuse could have prevented a few of these.

https://electricalcontractingnews.c...se-43-fires-a-week-in-england-research-finds/

 

[dobbslc]

^ mmm worth a look. I know my fan is on the lighting circuit with a 6 amp MCB, the fan switch is unfused but what's the fan rated for???

 

[Hotstuff]

Don't the regs specify equipment must be installed to manufacturers instructions? which often specify a 3A fuse for a bathroom fan.

Extractor fans are a cause of house fires, 182 for 2019/2020. Many are fitted to 10a or 6a circuits without fusing down the feed, it is plausible that a 3A fuse could have prevented a few of these.

https://electricalcontractingnews.c...se-43-fires-a-week-in-england-research-finds/

Bang on mate. There is no requirement under BS 7671 for local isolation to extract fans.
It’s very much thrown back to the circuit designer & installer to install the extract fan in accordance with the manufacture’s instructions.

That being said though, most sparks will, at the very least provide a means of local isolation.

Do ensure that whatever you install it is suitably IP rated for its location (zone) and it is protected by a fully functional 30mA RCD.

Rooms containing a bath or shower do have their own “Special location” section within BS 7671 for good reason.

 

[MetalMonkey]

I've known a building inspector actually hold off on signing because of a lack of a fan isolator, and usually when it comes to anything building and planning, its just easier to go along with it.
They aren't a bad idea IMO, so worth sticking one in anyway.

IIRC a 3A BS1362 fuse is going to pass something like up to 5A without bother anyway.
I reckon a 1A fuse would still be overkill for the current most these fans are actually pulling.