Connecting a fan to shower power

[tirfor]

Hi all, a newbie requiring advice.
I have been asked to fit a fan within a bathroom with the following constraints:
1. fan needs to work in daylight when light is off.
2. ideally on a timer so steam can be removed after showering.
3. humidistat not to be used as past units did not work to well.
4. be able to use 3a fans.
5. cheap as poss so no expensive fans or expensive pir's

So i have thought it would be best to connect the fan to the showers power.

My question is:
1. Is this ok to do or is there a better idea?
2. A timed fan requires a live and switched live, so is a fused spur available with twin fuses?
3. My idea is to tap into the supply side of the shower switch to provide the live feed and then tap into the load side of the shower switch to provide the switched live. Both lives will go to separate fused spurs (located in assessable attic) then both spurs will be connected to an isolation switch (in wall be bathroom door) then of to the fan. Is this ok or am i missing something?

Cheers for your help.

 

[ga8ry]

I've got it!!! Take it off the lighting circuit, but put in a pull cord instead of a pir. Place the pull cord beside the shower one. Tie them both together so when the shower is on so is the fan!!!!

IAM A GOD!!!

thread closed lol

 

[tirfor]

Wow! I never knew dummy spiting kids worked in the electric trade :rolleyes2:


Please do not comment on this thread unless you can be helpful and explain why certain ideas cannot be used with backed up evidence. Rather than just ranting on.


Thanks to all who have suggested why my original idea may not work due to the neutral. I’m still looking into that.


But I still haven’t had answers on why the shower circuit can’t be used as a power supply for another circuit and the use of junction boxes, even if the total current load is within the cables tolerance as per regs book?


Just too clarify, yes I can take the easy option of a humidity sensor or pir but as stated it does not solves the job brief. Ie past humidity fans fitted can be temperamental and a pir will cause the fan to run pretty much all day. If someone gives me a problem I like to try to solve it so they are happy, don’t you guys?


Thanks for the idea of a fan with a built in pir and timer, but the original fan hole is already at the far end of the bathroom where someone will not be able to walk past it in order to set it off. Making a new hole is not an option.


Thanks for the 3A idea, ie the lights circuit into the bathroom. Although this does solve the problem of using 3A fan it does not solve the problem of having the fan only work if the shower is in use.


What about the idea of a switching relay, anyone done it before?

 

[shanky887614]

Wow! I never knew dummy spiting kids worked in the electric trade :rolleyes2:


Please do not comment on this thread unless you can be helpful and explain why certain ideas cannot be used with backed up evidence. Rather than just ranting on.


Thanks to all who have suggested why my original idea may not work due to the neutral. I’m still looking into that.


But I still haven’t had answers on why the shower circuit can’t be used as a power supply for another circuit and the use of junction boxes, even if the total current load is within the cables tolerance as per regs book?


Just too clarify, yes I can take the easy option of a humidity sensor or pir but as stated it does not solves the job brief. Ie past humidity fans fitted can be temperamental and a pir will cause the fan to run pretty much all day. If someone gives me a problem I like to try to solve it so they are happy, don’t you guys?


Thanks for the idea of a fan with a built in pir and timer, but the original fan hole is already at the far end of the bathroom where someone will not be able to walk past it in order to set it off. Making a new hole is not an option.


Thanks for the 3A idea, ie the lights circuit into the bathroom. Where best to place the 3A fused spur?
Also if the bathroom light ring is not the last light point in the wire run do you suggest spurring of the light ring just to supply the bathroom and the rest of the light circuit continues at 6A?


What about the idea of a switching relay, anyone done it before?

Flow sensor in the pipework.

For example

www.automatedhome.co.uk/vbulletin/showthread.php?3503-Extractor-Fan-Control

 

[ipf]

Wow! I never knew dummy spiting kids worked in the electric trade :rolleyes2:


Please do not comment on this thread unless you can be helpful and explain why certain ideas cannot be used with backed up evidence. Rather than just ranting on.


Thanks to all who have suggested why my original idea may not work due to the neutral. I’m still looking into that.


But I still haven’t had answers on why the shower circuit can’t be used as a power supply for another circuit and the use of junction boxes, even if the total current load is within the cables tolerance as per regs book?


Just too clarify, yes I can take the easy option of a humidity sensor or pir but as stated it does not solves the job brief. Ie past humidity fans fitted can be temperamental and a pir will cause the fan to run pretty much all day. If someone gives me a problem I like to try to solve it so they are happy, don’t you guys?


Thanks for the idea of a fan with a built in pir and timer, but the original fan hole is already at the far end of the bathroom where someone will not be able to walk past it in order to set it off. Making a new hole is not an option.


Thanks for the 3A idea, ie the lights circuit into the bathroom. Where best to place the 3A fused spur?
Also if the bathroom light ring is not the last light point in the wire run do you suggest spurring of the light ring just to supply the bathroom and the rest of the light circuit continues at 6A?


What about the idea of a switching relay, anyone done it before?

OK............................No Comment!!!!!!!!

 

[ga8ry]

What my tying two cords together idea not good enuf for u??

 

[tirfor]

A flow sensor could work, thanks I'll look into that too.

No sorry, although a good idea I don't think the client will be happy to see that design in the bathroom. LOL

 

[telectrix]

and what if the guy does a stinky dump. will he need to run the shower to get rid of it, or strip off and dump in the shower??

 

[GLENNSPARK]

and what if the guy does a stinky dump. will he need to run the shower to get rid of it, or strip off and dump in the shower??

i once saw where someone had curled one off in the bath....it was a student let...

 

[tirfor]

Smells not a problem its the steam build up which is ruining the bathroom which is more of a problem

 

[ChrisElectrical88]

Wow! I never knew dummy spiting kids worked in the electric trade :rolleyes2:


Please do not comment on this thread unless you can be helpful and explain why certain ideas cannot be used with backed up evidence. Rather than just ranting on.


Thanks to all who have suggested why my original idea may not work due to the neutral. I’m still looking into that.


But I still haven’t had answers on why the shower circuit can’t be used as a power supply for another circuit and the use of junction boxes, even if the total current load is within the cables tolerance as per regs book?


Just too clarify, yes I can take the easy option of a humidity sensor or pir but as stated it does not solves the job brief. Ie past humidity fans fitted can be temperamental and a pir will cause the fan to run pretty much all day. If someone gives me a problem I like to try to solve it so they are happy, don’t you guys?


Thanks for the idea of a fan with a built in pir and timer, but the original fan hole is already at the far end of the bathroom where someone will not be able to walk past it in order to set it off. Making a new hole is not an option.


Thanks for the 3A idea, ie the lights circuit into the bathroom. Although this does solve the problem of using 3A fan it does not solve the problem of having the fan only work if the shower is in use.


What about the idea of a switching relay, anyone done it before?

Buy a decent one instead of going for the cheap option then? Never had a problem with a Vent-Axia.

 

[Knobhead]

This thread is set to run and run.

















Unlike the fan!

 

[Guest111]

ok if you are determined to go down the route of connecting into the shower here goes,put a current transformer around the live on the load side of switch,connect this to a current sensing relay,then take a permanent live and neutral from the lighting circuit through this to the fan.should only cost about 60 quid but hey ho if that's the route you insist on going down and connecting to the shower.

 

[guest119]

ok if you are determined to go down the route of connecting into the shower here goes,put a current transformer around the live on the load side of switch,connect this to a current sensing relay,then take a permanent live and neutral from the lighting circuit through this to the fan.should only cost about 60 quid but hey ho if that's the route you insist on going down and connecting to the shower.

As post no. 9 Phil.

Boydy

 

[Guest111]

As post no. 9 Phil.

Boydy

yes but my way will take that bit longer,buying the individual bits and assembling it all,being as how he seems determined to turn it into a 3 day event lol.

 

[derek]

Manufacturers requirements take precedence over BS 7671, and the Vent axia ones I've seen specifically show on the wiring diagram spurring from a lighting circuit. That might be a clue.