Bathroom Extractor fan wiring issue

[Doran]

Hi there,

I've moved into my flat and the extractor fan is dead.
I'm about to get a new one but I am also thinking the wiring is a bit wonky anyway.

There is an isolator switch outside with current. And then the terminal in the bathroom itself (this is is of the bathroom terminal)
the white cable is going to the extractor fan.

Untitled

• Doran
• 8 Jan 2013
• 1

When the bathroom light is on AND isolator is on, all wires are live.
but
When the bathroom light is on AND isolator is off, Brown/brown & blue/Blue are dead BUT the red/brown & black/blue are live.

BUT
When the bathroom light is off, all wires are dead.

Is this correct as this configuration wouldn't allow for any fan to run once the light is off.

How should it be wired?

Thanks in advance.

 

[Taylortwocities]

You only have two wires going to the fan. For a timer fan to over-run you need permanent live, switched live and neutral.

The old fan probabl;y only worked when the light was on.

My guess is that the two wires you have are the switched live and neutral. Youll need to find the permanent live - probably it is where the red and brown come together in that terminal block.

You'll need a test meter to confirm these. NOT a neon screwdriver.

 

[PrenticeBoyofDerry]

How have you checked for voltage?
As the earth/CPC should never be live!
and you should also have neutrals that should not be reading voltage.
What type of isolator do you have and how is that wired up, as it seems that not all these conductors are power via the isolator.
May have also been used as an enclosure to make a joint connection.
How was the old fan connected and did it have an overrun connection?

 

[Doran]

hi folks,
all wires were tested with a voltmeter, so when i say live, i mean there is volatge.
so yep, i feel that when the fan did work, it only worked when the light + isolator were on.
I dont think there is a permanent live, as when the light is off, all wires carry no voltage according to my voltmeter. Ive not used a neon light. would that make a difference?

FYI, when the light is turned off their is no power to the isolator.
ive attached a pic to the isolator below.

Ive only been in this flat a sort while and it has never worked since ive been here, so i have no idea how it functioned before.

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• Doran
• 9 Jan 2013
• 1

 

[Taylortwocities]

You only have switched live and neutral in that isolator.

It is not wired for a timer fan. You also need a permanent live from that lighting circuit through the isolator.
You would need to run new cables to have a timer fan. Sorry

 

[PrenticeBoyofDerry]

As above the wiring has not been made for a timer/overrun, As you will require three cores & earth at the fan isolator. I have my doubts by the information you have given that it has been wired correctly anyway.
As seem not to do what I would expect.
and if you test between earth and neutral there should be no voltage, don't bother with neon testers they are unreliable.
There is link here to Ex-Fan circuit
//www.diynot.com/wiki/electrics:lighting:fan