another bathroom extractor question

[paul b b]

hello chaps,

i have not done a extractor for a while and cant think how i wired it in, is it twin between switch and light? or 3c&e?

awwww please help, the little gray matter is rapidly dissolving

 

[Apache]

3 core if you have an over-run so a sw live and a perm live

 

[NozSpark]

Depends on the type of fan you are fitting..

timed over run require perm live, switched live & neutral through isolator switch to fan

std only require switched live and neutral through isolator switch to fan

 

[paul b b]

ok thanks chaps,

now they are really fizzing.

right lets get this correct....first off, customer is yet to ge fans, though the only place it can go is next to a window (or can it go above the bath?) so if i want to run a cable in i should put 3c in as i could tidy away the other core if nessasry.

but as the wiring goes, twin in switch to light, ummmmm where does the fan get wired into? the light fitting?

 

[D Brennan]

ok thanks chaps,now they are really fizzing.

right lets get this correct....first off, customer is yet to ge fans, though the only place it can go is next to a window (or can it go above the bath?) so if i want to run a cable in i should put 3c in as i could tidy away the other core if nessasry.

but as the wiring goes, twin in switch to light, ummmmm where does the fan get wired into? the light fitting?

i wire 3 core from light fitting, then into triple pole fan iso then into transformer if 12v then into fan or straight from iso if 240v

 

[Apache]

ok thanks chaps,now they are really fizzing.

right lets get this correct....first off, customer is yet to ge fans, though the only place it can go is next to a window (or can it go above the bath?) so if i want to run a cable in i should put 3c in as i could tidy away the other core if nessasry.

but as the wiring goes, twin in switch to light, ummmmm where does the fan get wired into? the light fitting?

I put a wiring diagram in downloads for this

 

[NozSpark]

The regs do allow 230v fans in zone 1 IIRC, so long as they are IP44(??) and RCD protected... but TBH personally I would only fit SELV in zone 1

 

[paul b b]

thanks patch, just a thought though, if i am using down lighters i take it im better using the 4 way jb....

thanks again

 

[wozz]

you should be fusing the fan down aswel as per manufactures instructions if it requires.

 

[Evans Electric]

If the lighting is 3 plate take a 3 core from the JB that feeds your downlights ,L,SWL &N .

Fit 3 pole isol switch or fit spur in the incoming feed, RCD if there is'nt one, low-volt fan if over bath.

 

[paul b b]

thanks chaps.

is there a place where the fan is recomended? ie wall opposit door?

also is a fan still needed if the room has a window?

 

[batty]

If the lighting is 3 plate take a 3 core from the JB that feeds your downlights ,L,SWL &N .Fit 3 pole isol switch or fit spur in the incoming feed, RCD if there is'nt one, low-volt fan if over bath.

Don't forget cpc.

 

[Lee321]

Don't forget cpc.

normally class 2

 

[batty]

normally class 2

But cable still needs cpc especially if you have metal box.

 

[sellers]

To lay it out simpler paul. Where-ever your lighting loop is, be it Switch, JB or Light. Take 3core from there to 3pole isolator then to fan.

With your 3 cores connect 2 into Live and Neutral of the loop, and the final one in with the switch wire.

 

[NozSpark]

thanks chaps.is there a place where the fan is recomended? ie wall opposit door?

also is a fan still needed if the room has a window?

The best place for an extractor is as far away from the door as possible! (without looking stupid)

 

[Lee321]

But cable still needs cpc especially if you have metal box.

the CABLE does not.

a metal box for a fan? i think not

 

[batty]

the CABLE does not.a metal box for a fan? i think not

If you have a fan isolation switch with metal back box this will need earthing. Unless you are going to wire your fan in flex totally cable will need earthing. If you are going to wire your fan in flex you will need at least three cores. Three core flex is brown, blue and green and yellow so you will be using cpc of flex for a switch live which is very bad practice. I understand what you are saying that fans are double insulated although you will find airflow 01 and other fans do require a cpc. The reason I am pointing out cables should have cpc is because we have a lot of training electricians on this forum and I would not want them picking up your bad habits.

 

[Lee321]

If you have a fan isolation switch with metal back box this will need earthing. Unless you are going to wire your fan in flex totally cable will need earthing. If you are going to wire your fan in flex you will need at least three cores. Three core flex is brown, blue and green and yellow so you will be using cpc of flex for a switch live which is very bad practice. I understand what you are saying that fans are double insulated although you will find airflow 01 and other fans do require a cpc. The reason I am pointing out cables should have cpc is because we have a lot of training electricians on this forum and I would not want them picking up your bad habits.

i was specifically speaking of the fan where did i mention the metal back box? :innocent if you want to educate you need to explain so they don't pick up on your bad habits.

you've just virtually told them they can use the earth as a line conductor but its bad practice:coat

obviously you would earth the metal back box from there you would take only live and neutral to the fan. the only cables that require an earth as you put it are metallic covered cables such as swa.

 

[AAAMUSEMENTS]

i was specifically speaking of the fan where did i mention the metal back box? :innocent if you want to educate you need to explain so they don't pick up on your bad habits.you've just virtually told them they can use the earth as a line conductor but its bad practice:coat

obviously you would earth the metal back box from there you would take only live and neutral to the fan. the only cables that require an earth as you put it are metallic covered cables such as swa.

But if you need a switched and permanent live then you will need 3 conducting cores... meaning that you will need to use 3+E specifically to avoid using the CPC as a conductor?

And anyway surely it's good practice to include a CPC in all wiring anyway, in case for instance the fan is changed for another one that needs to be earthed sometime in the future...

:|

Edit: Just reread my post and realised that I have basically repeated what Batty has already said... which compounds my confusion as to why you are disagreeing with him!

?:|