changing a bathroom extract easy???? NOT

[DirtyDog368]

HELLO ALL,

i attended a customer with a reported faulty bathroom fan. It was the timer variety with a three pin connection.
I checked the pins and found there to be 240v present so i determined that the fan must be shot. 30mins later i get back with the new fan and connect up but it did not work.

the fan i baught was a ASX100T from greenwood air managment, (a good fan)
there is a three pole isolator switch on the wall outside
and of course the bathroom light switch

at the isolator there are three cables grey, black and brown
now here's the funny thing
when the light switch is closed and the lights are on, the black wire from isolator to the fan is the ony live cable
when the light swtich is open and the lights are off, the brown wire from the isolator to the fan is the only live cable.

from my understanding of the wiring diagram, in order for the ASX100T to work i need a switched live and a constant live.

So am i missing something?
Anyhoo i did try to access cables to rewire accordingly but they are hidden behind a suspended ceiling and access can only be gained by removing this ceiling which is not a real option as of yet.

!- any idea why the circuit is wired up two switch over live from one core to another - could it be a fault or was it supposed to be like that?
2- what options do i have to get the new fan SAFELY working.....

i have included the wiring instructons for the newASX100T fan (1st column 2nd row).....

thanks guys for all your help

DD368

 

[GLENNSPARK]

no Richard...i dont like it either.....i mean how the hell could anyone confuse the black as L2...surely anyone working on an install would know wether it was 3 phase or not?..lol....and as for the grey....L2 on 2 way switching....or perminant line....as here and sleaved brown of course....

 

[GLENNSPARK]

same with smokes n heats (interlinked)........

 

[vernam616]

Doesnt really matter what colour you use as long as its sleeved?, its not like the copper in the core is of a different grade or size

 

[needasparks]

seem to remember when the colours changed we had to de-neutralise the black which is why the colour conversion charts were printed with yellow becoming black.

 

[telectrix]

what a bloody good argument for going back to proper colours.. REWD, YELLOW, BLUE. we all knew what was what. BUGGER BRUSSELS ( except for their sprouts ). let's start a campaign for UK electrics, UK rules.

 

[Adam W]

I use grey (sleeved) as neutral as recommended by NICEIC and black (sleeved) as common (live) in a switch, permanent live or L2, although that is a different argument.

In this situation I would have a look at how the 3 core is connected, ie in the light fitting or in the switch, and see if there is anything untoward.

Another reason I do it is because flex either comes in 'brown, blue and g/y', 'brown, black, grey, g/y', or 'brown, black, blue, g/y', so you can always use the black as auxiliary live, and if there isn't a blue you can use grey instead.

 

[TPES]

you can't win! either you are an electrician asking for advice and get slated or you're a DIYer asking for advice and get slated, so what is this forum for, chit chat and the price of cheese

Ha ha.... Like it, good reply

 

[GLENNSPARK]

Another reason I do it is because flex either comes in 'brown, blue and g/y', 'brown, black, grey, g/y', or 'brown, black, blue, g/y', so you can always use the black as auxiliary live, and if there isn't a blue you can use grey instead.

a fair point Adam.....interesting to see how several different people use variations....there is identification of conductors (sleaving) going on here by all...but definately 2 camps emerging.....

 

[Doomed]

Grey sleeved blue and the sleeved brown black as the switched live for me.

Also the on site guide says the old wiring colours for 3 core flat and earth of red, yellow, blue have been changed for brown, black, grey

 

[hermetic]

I know! lets standardise all the colours all over europe, we could use red for live and black for neutral, green for earth, and we could use red/yellow/blue for 3 core and three phase, that would be much simpler!

 

[Dave_]

I agree with Richard!

When you described the fault it sounds like the two live cores (brown/black) are connected to the strappers of a two switch. Check the bathroom light switch! One should be on the common..

 

[needasparks]

If there was no neutral turning the light on would alternate potential between lives if using it to test with.

 

[DirtyDog368]

Gentlemen, i just like to mention this.
this site is of great value and in this day and age with hardly any apprentiships and few engineers willing to take on a young spark under their wing it is even more valued. ALl your opionion and even the occasioanl rant is taken with my appreciation and thanks.

Now with regards to my competance : I feel that I am in my right mind and have the technical knowledge and know how with respect to domestic electrics and hold certificates coming out of my wazzu...BUT I also appreciated that the real world is far removed from the class room. So in order to avoid smart arse responses I try my best to word my questions correctly......hence my first question was like so

1- any idea why the circuit is wired up two switch over live from one core to another - could it be a fault or was it supposed to be like that?

this question is simplly asking weather or not there is a manufacturer out there that makes a fan which operates on two live and a neutral. L1 and L2 and N and if when the lights are on L1 is the ONLY live and when the lights are off L2 is the only live..which is what is happening.

From what i have gathered here, thanks to the invaluable responses, there is no such a fan and therefore I will embark upon fault finding and start ripping up wires confidently knowing that i am doing the right thing.....

NOW isnt that a smart approach?

As tothe comment regarding testing between live and neutral.......that was uneccesary, but i suppose you have to let off steam somewhere.:elvis:

again many thanks to all those lekkies that take the time and effort to respond constructively....

 

[GLENNSPARK]

If there was no neutral turning the light on would alternate potential between lives if using it to test with.

hence the momentary change in light levels when switching a incorrectly wired 2 way......

 

[vernam616]

Gentlemen, i just like to mention this.
this site is of great value and in this day and age with hardly any apprentiships and few engineers willing to take on a young spark under their wing it is even more valued. ALl your opionion and even the occasioanl rant is taken with my appreciation and thanks.

Now with regards to my competance : I feel that I am in my right mind and have the technical knowledge and know how with respect to domestic electrics and hold certificates coming out of my wazzu...BUT I also appreciated that the real world is far removed from the class room. So in order to avoid smart arse responses I try my best to word my questions correctly......hence my first question was like so

1- any idea why the circuit is wired up two switch over live from one core to another - could it be a fault or was it supposed to be like that?

this question is simplly asking weather or not there is a manufacturer out there that makes a fan which operates on two live and a neutral. L1 and L2 and N and if when the lights are on L1 is the ONLY live and when the lights are off L2 is the only live..which is what is happening.

From what i have gathered here, thanks to the invaluable responses, there is no such a fan and therefore I will embark upon fault finding and start ripping up wires confidently knowing that i am doing the right thing.....

NOW isnt that a smart approach?

As tothe comment regarding testing between live and neutral.......that was uneccesary, but i suppose you have to let off steam somewhere.:elvis:

again many thanks to all those lekkies that take the time and effort to respond constructively....

Any competant electrician would look for the fault without the need of asking others, like i said if you were an apprentice/diyer , id have had more of a positive input

Heres an easier approach, DISCONNECT THE FAN AND TEST AT ALL POINTS, TAKE HEED OF THE 2 WAY SWITCH RESPONSE AS IT SOUNDS LIKE A GOOD ONE