Wiring timer fan to FCU

[NeedToSmile]

I'm putting a timer fan in the bathroom and it needs a FCU (3amp fuse). The fan will operate on its own seperate pull switch, independant of the light.

Can you please help me understand how to wire it.

I'll be connecting from the lighting junction box, but:

Do I take the 2c & e cable from the JB to the pull switch or the FCU first?

How do I proceed witht he rest of the wiring thereafter?

A FCU has only 4 terminals and a pull switch only 2(plus earth ofcos), so no matter which way I look at it I can't figure out the arrangement.

Please help.

 

[BigJon]

Are you not wanting the fan to run on when the lights go off as its a timer fan you have?
If you just want it to switch on with a pull cord you may not be able to use your timer fan.
Some fans if you loop the live and timer connections out it will work as an on/off but not all.

 

[NeedToSmile]

BigJon no want the fan to operate independant of the lights (long story mate).

The instructions do mention that you can do this, but the wiring diagram leaves much to be desired.

Running it of the lights via a 3P isolator is a doddle, but have never wired one via a seperate switch and FCU and the whole thing has me a bit baffled .

Would welcome your help guys.

 

[securespark]

You can have an independent switch for the fan AND still use a timer fan.

If it needs to be fused down, then take your L/N/E feed from the ceiling rose/junction box into the FCU, then come out with T & E into the pull cord for the fan. Fit a 1/2/3A fuse.

Leave the pull cord with 3 core & earth which goes to the fan. You would normally need a 3 pole switch for maintenance, but in this case, use a switched FCU and switching that off will isolate the fan entirely.

"Ah, what about connections?" I hear you ask....


Think about it for a while, then get back with your ideas. If you need help, we're happy to give it. Just that I'm keen to know how you think it should be wired.

 

[NeedToSmile]

Thanks securespark.

Connecting at the pull switch, lets see:

1=Join the 2 N outside of the switch, in say a Chocbox.

2=Connect the L from the T&E to the L (permanent) of the 3C&E.

3=Connect the L (switched) from the 3C&E to the other terminal.

Which part did I get right (if any ) ?

 

[securespark]

Not bad!

Take the feed into the switched FCU into the feed terminals. Take the outgoing (load) cable to the pullcord & connect the N to the neutral core of the 3 core (sleeve it blue).

Take the live of the twin & earth to the switch common, along with the permanent live core of the three core. Connect the third core of the three core cable to L1 on the switch (or L2, it does not matter as it is a pullcord)

Wire the fan to the other end of the three core.

Hey presto! A timer fan operated independently of the light on its own pullcord switch and isolated via the switched FCU.

 

[NeedToSmile]

Thank you so much securespark

There's not much space inside a pull switch fitting, so was thinking instead of connecting the N and sleeving them together inside the fitting, that instead house them in a chockbox http://www.screwfix.com/search.do?_dyncharset=UTF-8&fh_search=chocbox&pn=1&pd=1&pi=1&cn=1&cd=1# in the ceiling void to one side of the pull switch.

What you think?

Once again many thanks

 

[empip]

You may find it handy for the pull switch to have 'on / off' indication.
Otherwise when the kids have used the thing and you are about to leave the house - you may wonder 'is it on or off ?'.. If you can reach the iso' switch then that'll kill it.

 

[NeedToSmile]

Thanks securespark & empip.


securespark, would the following arrangement also work?

Take T&E from JB to FCU (fused to 3A).
Take T&E from FCU to pull switch.
Take 3C&E from FCU to timer fan.

At the FCU:

1= Connect L (permanent) from 3C&E to the output L terminal.

2= Connect N from 3C&E to the output N terminal.

3= Connect L (switched) from 3C&E to N (switched live) of T&E from the pull switch, in a seperate terminal block. http://www.screwfix.com/app/sfd/cat/pro.jsp?cId=A331811&ts=49174&id=32116

4= Connect L from pull switch T&E to the output L terminal.

Am just thinking of the space available in the pull switch and making it neater/easier to work with in future.

What do you think?