Wiring for extractor fan

Hi, When I went to replace the extractor fan in the downstairs toilet, I found it was wired to three identical looking grey wires. I know little about electrics but had expected to find the old live/neutral/earth colour coding....any ideas as to what I have found and how I should connect it to the new fan? The house is about seven years old. Cheers, Peter
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themirrorballman wrote:

Ignoring the colours of the wires, are the terminals they are connected to not marked in some way? If so put appropriately coloured tapes round the wires before disconnecting them so you know which is which.
Note also that fans that are switched (or triggered) from the light switch will have one Neutral, and TWO lives (switched and permenant) this is how they do the timer run on.
Many will be double insulated and hence not have an earth connection.
Hence oyur three wires could be L, N and E, or they could also be L, SL, and N.
If there are no markings at all then you will need to work out which is which with a multimeter first.
--
Cheers,

John.

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themirrorballman wrote:

More info please:
Where do the grey wires come from - are the connected to the rest of the house wiring by a junction box or something similar that you can see?
Does your fan have a timer, ie does it stay on for a while after being switched off?
Are there markings on the three terminals on the fan where the wires connect?
How does the fan turn on and off: does it have a dedicated switch, or does it come on only when you turn the lights on?
David
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Thanks for the replies John and David. The answer to your questions are below:

They go into the ceiling - I can't see where they go to after that.

Yes
Yes L,N,S/L.....plonker that I am, I disconnected the grey wires without labelling them.

Comes on with the lights
I have an idea how the grey wires were connected to L,N,S/L but am not 100%.....will I blow the place up if I have a go and get it wrong.....? Sounds like John's multimeter suggestion might be the way to go.
Thanks again, Peter (feeling a bit of a prat)

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It is possible that these grey wires actually heatproof covers for the normal colours underneath.
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together this:

Sounds like single core double sheathed cables, (6181Y).
--

SJW
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Bullseye I cut them back a bit and have two brown and one blue underneath....does this mean no swiched live? Can I hook the fan up and have it work without the timer - or is wiring it like this the reason the original fan wasn't working when I moved in........?
strung

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themirrorballman wrote:

Ah - so as far as you're concerned, the fan has never actually worked? If so, you didn't mention that crucial little piece of info before, and yes, that could mean the original wiring could be completely wrong ansd the old fan was not faulty. But you said before that the fan stayed on after the light went off, implying the timer was indeed working... bit confused here!
There has to be a switched live and a permanent live (which will probably be the two brown wires you can see) for a fan to work on overrun after the light has been switched off.
David
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themirrorballman wrote:

I'm reluctant to spell it out, as you seem to be dangerously the wrong side of the clue boundary... but... let's see how close we can lead the neighing quadruped to the aquifer...
'Brown' (as flex only, until recently) suggests A[ ] live B[ ] neutral C[ ] earth D[ ] dunno-don't-care
'Blue' suggests A[ ] live B[ ] neutral C[ ] earth D[ ] dunno-don't-care
Now, what was your score? If one or more C or D answers: step away from the fan, step away from the ladder. Learn to open a window in the bathroom, save up for an electrician to visit. If your answers to both parts are identical - same business: step away etc., save up etc.
Otherwise: arrange the following words into a relevant order: live switched permanent live neutral
To work out which of the wires that are not, in the words of Sesame Street, 'one of these colours is not like the others, one of these colours is not quite the same' is which, you need something to detect mains voltage. If you have a meter and the ability to use it, do so; if all you have is a neon screwdriver, that'll do. Clue: one will be live all the time, more or less, well, not temporarily, the opposite, y'know, like the ground some way down near the poles which gets called the 'permafrost', maybe you can guess the word I'm thinking of; the other one will be affected by the two-position current-interruption-device whose normal name rhymes with 'witch' and 'ditch'.
And if it all goes phut, bang, spark, with you going twitch, twitch, smoke - maybe you should've been more honest in marking the first part of the quiz...
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Thanks for having the patience to help me on this guys. You'll be glad to hear (I hope) that no twitching or smoking was involved and having passed Stefek's test, I identified the permanent and switched using a neon screwdriver. The fan is now installed and working.
Sorry for the confusion earlier David - I answered yes to the "does the fan have a timer" part of the question and not the latter part. I should have made it clear that the fan had never worked.
Thanks again, Peter

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