Wiring a bathroom extractor fan

[bhamoggy]

Ive not done one before and have to fit one this weekend.

Taking the switched live and permanent live from the bathroom light fixture, I'll terminate into an isolator then into the fan giving me a switched live, a permanent live, a neutral and the cpc.

The question I have, do the cables need to go to fused spur before the isolator? If they do, how would you wire that being there would be 3 poles going into the fcu.

Thanks

 

[SLIPSHOD & SLAPDASH]

Do a search and you will find many threads on this. The majority of people do not fuse down the fan, although the manufacturer says you should. Even the NICEIC inspector has never questioned me on it.

 

[bhamoggy]

Do a search and you will find many threads on this. The majority of people do not fuse down the fan, although the manufacturer says you should. Even the NICEIC inspector has never questioned me on it.

So straight from the light, into an isolator, that's it?

 

[batty]

Why not use a three pole isolator IE fan switch?

 

[SLIPSHOD & SLAPDASH]

Thats your desision. If you follow the instructions you have to fit a 3amp fuse before the light switch so the light and fan are both running through it. This also has to be connected through a rcd unless everything is bonded up. This is also notifiable work under Part P of the building regs.

 

[SLIPSHOD & SLAPDASH]

Why not use a three pole isolator IE fan switch?

He is

 

[Doc Hudson]

Thread moved. Manufacturers instructions will normally show wiring examples.Doc H

 

[Andy™]

If you follow the instructions you have to fit a 3amp fuse before the light switch so the light and fan are both running through it.

not always - you can use a DP switch, keeping only the fan on a FCU

also, if he fits an inline fan in the loft, then it may not need RCD'd, or notified

 

[Revved Up Sparky]

You don't have to activate it with the lighting switchwire, for example, you could control it with a separate switch or perhaps a PIR.

 

[SLIPSHOD & SLAPDASH]

[quote name='Andy

 

[Andy™]

You may be correct, but i have just done a quick sketch & cant work out how. I will look again now whilst you tell me :Salute

light wired as normal through one side

for fan, FCU, then to switch. perm live taken from supply side, sw. live taken from load side. neutral from FCU.

done similar a few weeks ago - common fan between 2 bathrooms

 

[SLIPSHOD & SLAPDASH]

[quote name='Andy

 

[Steve3948]

Most fan manufacturers (decent ones) have dropped the sole wording fused at 3A, and state from a Lighting Circuit or fused at 3A.

So if its a utility fan wired to FCU fuse at 3A, if bathroom fan off lighting circuit.

Greenwood and the latest Vent-Axia say the above.

 

[bhamoggy]

[quote name='Andy

 

[SLIPSHOD & SLAPDASH]

Here's a (very) rough schematic for you. A method uses a double pole switch & fuses fan only to 3A. B method uses a single pole switch but fuses both light & fan to 3A. If RCD protection is required you could swap the unswitched spur for a RCD spur.

Edit, forgot the diagram...

 

[steptoe]

but,

in slips diagram you have still not fused the fan to 3 amps,

merely the permanent liver,

Im sure he will correct this for you though,

---------- Post Auto-Merged at 00:49 ---------- Previous post was made at 00:47 ----------

ah, sorry, my correction, but, Im still puzzled as to why he has done it this way, :|

 

[SLIPSHOD & SLAPDASH]

A is wired so the 3A fuse protects the fan only and not the light.

 

[steptoe]

A is wired so the 3A fuse protects the fan only and not the light.

yep, I did get it on the second look,

sorry for the confusion, I did edit,

its just more overly done then my usual retro-fit if I have to actually fit a 3A protection device.

I like to keep things simple,

like me.

 

[Zeespark]

View attachment 4089

I hope that has worked.

AndyGuinness

 

[bhamoggy]

A is wired so the 3A fuse protects the fan only and not the light.

Thanks for the diagram, very helpful

---------- Post Auto-Merged at 08:46 ---------- Previous post was made at 08:45 ----------

View attachment 4089I hope that has worked.

AndyGuinness

Link doesn't appear to work?