Fuse in extractor fan circuit

[drood]

I want to install a timer fan in a bathroom. I have looked at previous posts but not found an answer to this directly. It is new, complete with instructions and diagrams, but it shows that even if it is incorporated into the lighting circuit a fuse should still be inserted before the light switch which will operate it.

I am proposing this:
Break into lighting circuit before relevant rose or junction box and install a 5A FCU. Then either at rose or JB, connect Live, Neutral and Switched Live to relevant terminals, then take this cable to a 3 pole isolator outside the bathroom, then direct to the fan.

Would this suffice?

Many thanks.

 

[another_sparky]

You will need to fit a fan isolater
( This enables you to remove or service the fan without having to turn off your lighting.)

Easiest way is to fit a Switched Fused Connection Unit ( FCU) between the lighting pull cord switch unit, and the fan itself.

If you have room on your bathroom ceiling you could mount the FCU alongside the pull cord - This tends to make the FCU less noticeable.

Alternatively, you could mount the FCU alongside the fan (but I think its more obtrusive and not very aesthetic)

Of course, dont forget to knock off the supply before you break into the circuit.

 

[securespark]

you could feed the bathroom lighting & fan via an fcu like this:

take the live loop out of the jb or rose: this goes to feed terms of fcu.

the load side goes to jb or 3 plate batten. Your switch cable is reinstated as before, then you take L, swL and N to fan via 3 pole iso as you described.

It does not have to be outside: if you want to use a pull-cord, Ashley make one.

I would use a 3A fuse, though.

If you want to control the fan from a different switch to the light switch, then just tap off the lighting to a 3A fcu and the load terms of the fcu feed the fan via a sep pullcord switch. Using this method you don't need a 3 pole iso, as when you switch off the fcu, all the fan wiring is isolated.

This is true of the method described above, but fitting a 3 pole iso in the first example gives you the ability to iosolate the fan without switching off the lighting.

 

[securespark]

Easiest way is to fit a Switched Fused Connection Unit ( FCU) between the lighting pull cord switch unit, and the fan itself.

AS, this is a bit ambiguous: do you mean to say fit an fcu in the live and switched live conductors?

 

[drood]

Securespark - when you wrote:

take the live loop out of the jb or rose: this goes to feed terms of fcu.

the load side goes to jb...

Is the jb in the second line the same one that you took the live loop out of?

 

[securespark]

Yes. Basically what you're doing is using the existing live feed(s) (loop) to supply the bathroom lighting etc via an fcu.

So the loop is removed from the existing termination point, redirected to an fcu, then the cable that comes from the load side of the fcu supplies power to the fitting or jb (where before the loop was connected).

This sounds a bit confusing, but I hope it now makes sense!

 

[ban-all-sheds]

You will need to fit a fan isolater
( This enables you to remove or service the fan without having to turn off your lighting.)

He said he was going to do that - re-read the 2nd para of hs post.

Easiest way is to fit a Switched Fused Connection Unit ( FCU) between the lighting pull cord switch unit, and the fan itself.

It's a timer-overrun fan, so he'd need 2 FCUs, one in the switched live, and one in the permanent live.

Drood - you should do basically what you said, but unless the bathroom light is the last one on the circuit, don't put the FCU into the circuit, because if you do that you'll lose all the downstream lights if the fuse goes.

Take the wires out of the ceiling rose, and connect the loop-in and loop-out cables to the supply terminals of the FCU. Connect the load side of the FCU to the Neutral and Loop terminals in the rose, and then run your 3C+E cable from there via the isolation switch to the fan as per normal.

BTW - the isolation switch does not have to be outside the bathroom, nor does it have to be a pullcord one - provided it's in Zone 3 or outside the zones it can be inside the bathroom if you want.

 

[securespark]

Take the wires out of the ceiling rose, and connect the loop-in and loop-out cables to the supply terminals of the FCU. Connect the load side of the FCU to the Neutral and Loop terminals in the rose, and then run your 3C+E cable from there via the isolation switch to the fan as per normal.

Isn't that what I was saying??

 

[drood]

That's very helpful - and clear in my mind now. Very useful info, as always!

Thanks.

 

[ban-all-sheds]

Isn't that what I was saying??

Yes, but you sneakily started saying it after I started my post, and sneakily finished it before I finished mine.

 

[securespark]

Sorry to be so sneaky!