wiring extractor without isolating switch?

[Edd1982]

Hey guys, first post so Hello to you all.

Our bathroom extractor has given up so i've just been out and bought a new one (Marley NDX100T). I thought it would be a quick "take old one off and bung the new one up" job

The fan comes on with the light, and goes off via a timer.

The old one (10 years old plus) has a feed from the light switch to it (2 core?) and another wire (3 core?) that gos to the light in the next room. Inside the extractor theres a block connector and the wires go to a small circuit board (timer etc).

The wiring diagram for the newie mentions a double pole isolating switch. Do i need to install one of these too, or is there a way around it? Not bothered if i have to do without a light when cleaning etc.

Bit clueless when it comes to electrics, but willing to learn and grateful for any help/advise. Willing to swap for hydraulic advise if need be

 

[riveralt]

You should follow the manufacturers instructions.

If it is a timer model then it will require three core and earth - one of the cores will be permanent live, the other switch live and the third neutral plus cpc.

If you want the fan to activate when the light is switched on then you run the switch live cable from the ceiling rose switch live to a three pole isolator located in a safe zone or outside the bathroom. The permanent live runs from the ceiling rose live loop and the neutral from the ceiling rose neutral loop - same for cpc again to the three pole isolator.

From there run three core to the fan and wire as instructions state.

 

[ricicle]

Do the instructions state where the isolator has to be ?

 

[Edd1982]

No it doesn't state where it has to be? Do i definately need one? Just don't want to have to fit this switch and wiring if i don't really need to.

 

[ricicle]

The main switch of your CU can be the isolator if you like, or the fuse/circuit breaker if you are on a TN system.

 

[riveralt]

Do the instructions state where the isolator has to be ?

The Manufacturers instructions state that there is a requirement for an isolator - no fcu if the power is coming from the lighting circuit.

Have a read for yourself.

http://www.google.co.uk/search?hl=en&q=Marley+NDX+100+instructions&meta=

 

[Chri5]

Do the instructions state where the isolator has to be ?

The Manufacturers instructions state that there is a requirement for an isolator - no fcu if the power is coming from the lighting circuit.

Have a read for yourself.

http://www.google.co.uk/search?hl=en&q=Marley+NDX+100+instructions&meta=[/QUOTE]

It's purely choice, provided:-

Room has natural light.

Isolation in the local area is required to service the fan. Obviously if the bathroom had no natural light then turning the main circuit off as a 'form' of isolation would mean working in the dark.
So in the above instance it's required.

If you have natural light and are ok with turning off the circuit at the board local isolation is not mandatory- no matter what the manufactures instructions say.

OP your choice....

 

[riveralt]

If you have natural light and are ok with turning off the circuit at the board local isolation is not mandatory- no matter what the manufactures instructions say.

OP your choice....

I must disagree with you statement!

17th edition 134.1.1............"Electricial equipment shall be installed in accordance with the instructions provided by the manufacturer of the equipment".

As you say be Part P and 17th edition compliant.

 

[Chri5]

Riveralt

I see why you disagree with my statement, but lets use some common sense.

Are you suggesting that any retro mtce replacement of a simple fan must have local isolation ?

Or are you saying that the manufactures instructions MUST BE adheared to ?

So a generic installation instruction for a product made in Asia is an absolute manditory requirement ?

So what shall we do with the couple of million fan installations that do not have 3p isolation ?

 

[holmslaw]

..