Can i fit this extractor fan above my bath?

[ban-all-sheds]

Instruction for wiring say:

A double pole fused spur must be used, fitted with a 3 amp fuse, sited outside the bathroom.!

Just the one?

It has a timed overrun, so it needs a permanent live feed and a switched live feed, so I wonder how they expect you to do that with just one fused supply?

And as it does have those feeds you will also need a 3-pole isolation switch.

 

[securespark]

Ban

It can be done by taking the live feed(s) from the existing bathroom light fitting and feeding the spur with them, then the outgoing terms feed the light via the existing switch, and you tap off these feeds for the fan. Thus, when the dp switch is off, so is the fan. The drawback with this system is that the bathroom light(s) go out too.

 

[ban-all-sheds]

Of course - 3A would be plenty for the fan and the bathroom light. I do wonder why they specify that, though - the fan normally takes 89mA, I can't think of a fault condition in the fan where a 3A fuse would protect the fan against damage.

As for lights being off when you turn the fan off, this is often the way - controlling a timed-overrun fan with the lightswitch.

 

[securespark]

I meant that when the spur is off, so is the light, whereas if you fit a triple pole isolator (TPI), you can isolate the fan independently of the light.

BTW, Ashley make a pull-cord TPI.

 

[tonyrobbo]

Could you just run through one more time how to wire it to a double pole fused spur and to my existing light switch and still allow the timer to work?

Also do i need to buy 3 core cable and can i fit the spur in the loft?

Thanks for your help!

 

[securespark]

Ban

It can be done by taking the live feed(s) from the existing bathroom light fitting and feeding the spur with them, then the outgoing terms feed the light via the existing switch, and you tap off these feeds for the fan. Thus, when the dp switch is off, so is the fan. The drawback with this system is that the bathroom light(s) go out too.

OK. Start at the light fitting or junction box where the permanent live feed(s) come in.

Remove these cables (or cable if it is the last on the circuit) from the fitting, rose or jb and wire them into a switched fused spur on the "FEED" side. Then you take a fresh piece of cable wired from the "load" side of the FCU and that feeds the light fitting via the switch, just like it did before, only with this new system, the feed is via the FCU's 3A fuse.

OK, so now you have a bathroom light switched from the existing switch just as before, the only difference is that when you switch off the FCU, the bathroom lighting circuit is isolated.

Now all that remains is to connect a three core and earth cable taken from the permanent live (ie the wire from the live "load" terminal of the fcu), the switched live (from the switched live that feeds the light fitting) and the neutral. These connections can be sourced from any convenient point on the bathroom circuit, but it may be easiest to group these connections in a jb. The other end of the 3 core & earth cable feeds the fan.

You don't need a 3 pole isolator, because the live (and switched live and neutral) are all isolated the moment you switch off the DP FCU. As I said to Ban, the only drawback to this circuit is that the light as well as the fan goes off when you operate the FCU switch, whereas with a triple pole iso, you can just isolate the fan, and leave the rest of the circuit live.

Hope this is OK. Any more queries, just post.