Extractor Fan-too simple to be correct?

[Jolyonwag]

I need to put an extractor fan in a small downstairs toilet with no window. I know it has to be fused to 3amps and I know it has to have a run over facility, and that it must be linked to the light switch/switch to conform to building regs. It will be a staff toilet and I am aware that people will forget to turn off the light/fan as they leave the toilet, so it could be running all day. For this reason I will probably go for an airflow with a pir detector installed.
I have been reading on the forum about triple pole isolators, fused spurs, and all sorts of different opinions about how to install an extractor fan. My question is: is this correct:

Live feed from toilet light rose to switched 3A fused spur outside the toilet room (1.5 T&E). fuse spur to extractor (L + N only)

Many thanks in advance

 

[Des 56]

I need to put an extractor fan in a small downstairs toilet with no window. I know it has to be fused to 3amps and I know it has to have a run over facility, and that it must be linked to the light switch/switch to conform to building regs. It will be a staff toilet and I am aware that people will forget to turn off the light/fan as they leave the toilet, so it could be running all day. For this reason I will probably go for an airflow with a pir detector installed.
I have been reading on the forum about triple pole isolators, fused spurs, and all sorts of different opinions about how to install an extractor fan. My question is: is this correct:

Live feed from toilet light rose to switched 3A fused spur outside the toilet room (1.5 T&E). fuse spur to extractor (L + N only)

Many thanks in advance

You want to use the light to trigger this fan ?
You want timed over run ?
You want to wire only l+N ?
Do you want to think again

quote
outside the toilet room
Why ?

 

[telectrix]

fit an occupancy sensor to the light. then connect the fan to the light L,S/L and N through a 3 pole isolator. 3A FCU if manufacturers instructions call for it.

 

[Jolyonwag]

fit an occupancy sensor to the light. then connect the fan to the light L,S/L and N through a 3 pole isolator. 3A FCU if manufacturers instructions call for it.

Sorry, but I thought this product (AIRFLOW QUIET AIR QT100PIRT QUIET EXTRACTOR FAN)


had a built in motion sensor. Could you please explain the need to fit an occupancy sensor, and the extra wiring.

Airflow QT100PIRT Quiet Extractor Fan with Motion Sensor and Timer

Many thanks

 

[Jolyonwag]

You want to use the light to trigger this fan ?
You want timed over run ?
You want to wire only l+N ?
Do you want to think again

quote
outside the toilet room
Why ?

sorry, no i want to take the live and neutral from the toilet light fitting
yes i wan the fan to continue removing the air after the occupant has left the toilet and the fan sensor is not detecting movement in the room.

Yes Live and neutral, because the product is double insulated and does not require an earth [h=1]AIRFLOW QUIET AIR QT100PIRT QUIET EXTRACTOR FAN[/h]

Outside the room, because of the wash basin and zoning rules

 

[telectrix]

zoning only applies if a bath or shower is in the room. occupancy sensor so that lights and fan go off after client has left the room and is too lazy to turn the light off.

 

[Jolyonwag]

zoning only applies if a bath or shower is in the room. occupancy sensor so that lights and fan go off after client has left the room and is too lazy to turn the light off.

Thanks for this, makes sense, and I may well now go this route. Hopefully there are no issues with occupancy sensors and
energy saving 2D style CFL lamps!

However, if i were prepared to swallow the lighting bill, would my first scenario be correct? And I appreciate the switched spur can be in the toilet.

ie live and neutral straight to extractor via switched 3A fused spur

Many thanks

 

[telectrix]

yeah.keep it as simple as you can. the more you complicate it, the more there is to go ---- up.

 

[gutterball]

how are you going to achieve overrun with only 2 cores?

 

[Jolyonwag]

how are you going to achieve overrun with only 2 cores?

I thought that the module that can be purchased as an extra would handle this. In my case it would be the pir timer module

 

[telectrix]

yeah' you can use the pir as a timer for the light and/or the fan.