Bathroom Extractor Fan Wiring

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Currently, in my loft, I have a junction box with 4 twin and earth cables connected in it.

Cable 1 brings the power from the fuse box.
Cable 2 passes the power onto the next light in the circuit.
Cable 3 goes to the pull switch in my bathroom.
Cable 4 goes to the light fitting in my bathroom.

The Live(s) from 1, 2 and 3 are all connected.
The Neutral(s) from 1, 2 and 4 are all connected.
The Live from 4 and the Neutral from 3 are connected to give me my switched live.
All 4 earths are connected.

I think/pressume this is a fairly standard way to wire up a light?

All 4 terminals in the junction box are being used as are the 4 entry points to the box.

I want to install a fan on a timer.

I've already positioned/installed the fan and isolation switch and wired the fan to the switch with 3 core (+ earth) cable.

Now I need to connect the other side of the isolation switch to the lighting circuit.

I thought it was going to be as simple as:
Connecting the permanent live to the live(s) from 1, 2 and 3 in the junction box above.
Connecting the neutral to the neutral(s) from 1, 2 and 4 in the junction box above.
Connecting the switched live to the switched live/loop terminal in the junction box above.

Question:
Is it that simple?
What do I do about the fact the junction box only has 4 entry points into it?
Can you buy a junction box with 5 entry points?


Help and advice would be really appreciated.

Many thanks,

C.
 
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You are correct about which connections to use. (Assuming you will be connecting the earths too!) You may be able to knock out a bit more of the cable entry hole to get two cables one above the other. If the box is still too small, replace it completely. A 4 terminal 20A box will do the trick.
 
... unless you are fitting an in-line fan with all connections made in the loft? :?:
 
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ban-all-sheds...

I know it's not a neutral - sorry for the confusion.
I was trying to explain it based on the colour of the cable.
It would normally be used for a neutral but in this case it is the switched live and I've wrapped some red tape around it so people know.

Also, yes the isolator switch is outside the bathroom.

Sparkyspike...

I'm not sure what you mean?
The pullcord for the bathroom light is ceiling mounted so I guess that qualifies as connection in the loft?
The fan is low profile ceiling mounted, again I think that qualifies.
The isolator switch is above the bathroom door (switch on the outside) in a stud partition wall.

Does that qualify as "an in-line fan with all connections made in the loft"?
 
Sparkspike...

Forgot to say, the fan doesn't need an earth (or have anywhere to connect one). Neither does the switch have anywhere to connect one and obviously the plastic patress I'm fitting the switch to doesn't have an earth point either.

So no, none of this is going to be earthed.
 
I guess my original question was is it ok to have 5 cables coming out of a 4 terminal 20A junction box, and according to sparkyspike it is!

Unless I hear differently by tonight I'm going for it! Wish me luck or listen for the bang! :)

Thanks for the replies, much appreciated.
 
The answer to your original question is yes, you can add the fan wiring to your 20A JB. But as you are fitting a mains voltage ceiling fan, it still qualifies as notifiable work. It is inside the bathroom. Make sure you connect the earths at the jb, and make a proper termination inside the fan, even though it's not being connected to anything.
 

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