I need some help please, fitting extractor fan.

[Hardley26]

I am about to replace an old extractor fan in my utility room, old fan supply came from 3 amp fused box, with Live. Neutral, Earth all 3 cables went to the fan, which operated by a pull cord on the fan.
The new fan has a timer fitted and is earthed, it has 3 connection points, Live, Switched Live and Neutral.
I was thinking of putting a 3 pole isolator pull cord switch, between the 3 amp fused box and the fan.
But I need to know where can I get the extra Live cable from, could I put 2 cables into the Live connection in the 3 amp fused box, and then make them Live and Switched Live in the 3 pole isolator switch.
Thank you
Hardley

 

[1john]

Why a 3 pole switch, if you leave the DP 3A switch spur there and install a SP pull switch you can lave the switched spur on all the time and use the SP pullsord to over ride.

 

[Hardley26]

Have not bought the 3 pole switch yet, so could fit an SP as you suggest, yes the 3 amp fuse box would be switched on all the time.
My main concern is where do I get the extra Live cable from, would it be Ok to put 2 cables into the Live connection in the fused box?

 

[riveralt]

Your single pole pull switch will have common and L1 terminals.
From your switched Fused Connection Unit run the line to the common terminal and your neutral to a terminal block and put the earth into a separate terminal block.

Use three core & earth from the single pole pull switch to the fan. Put the brown core into the common (this is your permanent live) put your grey core (with brown sleeving) into the L1 terminal. Connect your black core into the neutral terminal block and put your earth into the earth.

At your fan put the brown core into the PL, your grey core(with sleeving) to the SL and the black core to the neutral. Technically it would be correct to put blue sleeving around the black core to indicate it is being used as a neutral. Put your earth into the earth terminal.

Couple of things.

FIRSTLY... Your Fused Connection unit must be double pole - this means that it isolates both Line and Neutral. Not all FCU's are double pole - so check that it is written on it somewhere.
SECONDLY... when you work on the fan you MUST turn the FCU off and remove the fuse. Otherwise you will still have a permanent live at the fan.

Finally, not very many extractor fans have an earth connection most are double insulated - check that you are following the manufacturers instructions.

 

[ban-all-sheds]

And do not, under any circumstances, be tempted to use the existing twin & earth cable to the fan to carry L/SL/N - you must replace the cable from the pull-switch onwards with 3-core & earth.

 

[Hardley26]

The fan does not require an earth, but I was going to take earth as far as sp. and I will be fitting new cable through out.

 

[riveralt]

The fan does not require an earth, but I was going to take earth as far as sp. and I will be fitting new cable through out.

You will need to run the cpc (earth) as far as the fan and terminate it there. This will allow you to conduct the continuity tests using the full length of the cable to get your R1+R2 figures. Once tested isolate the cpc so that it cannot come into contact with the other cables or anything metal.