Hi all,
I have to install an extractor fan into our upstairs bathroom and
have a couple of questions to anyone who might have done this:

Firstly, should I drill from the inside going out or the outside
going in? And secondly are there any unforeseen complications that the
novice DIY person like me might miss and should I call a professional?

Many thanks
Sam

"Caher" wrote in message
m...
Hi all,
I have to install an extractor fan into our upstairs bathroom and
have a couple of questions to anyone who might have done this:

Firstly, should I drill from the inside going out or the outside
going in? And secondly are there any unforeseen complications that the
novice DIY person like me might miss and should I call a professional?

Many thanks
Sam

Just done this for the first time in my kitchen...

I would start on the outside. Spend some time working out
whether both sides of the bit of wall you intend to drill through
are actually clear. A drainpipe across the front of your fan
will not help! Assuming you have cavity walls, I would make
the appropriate size whole in the outer skin from the outside,
then drill pilot holes through the inner skin so that you can see
where the fan will be. Then, I would drill out the rest from the
inside.

A handy hint: get a big cardboard box and duct tape it to the
wall below where you'll be drilling. Stone dust is a pig to get
out of tile grout etc. The box should catch most of it.

HTH,
Al

"Caher" wrote in message
m...
Hi all,
I have to install an extractor fan into our upstairs bathroom and
have a couple of questions to anyone who might have done this:

Firstly, should I drill from the inside going out or the outside
going in? And secondly are there any unforeseen complications that the
novice DIY person like me might miss and should I call a professional?

Many thanks
Sam

The minimum effort/maximum cost way is to hire a core drill and just bore
straight through.

Minimum cost/maximum effort is to bore a number of holes then knock the wall
out with a hammer and chisel.

As to 'inside out' or 'outside in' you may have to drill from both sides
unless you have a very long drill.

Don't worry too much about damage around the hole, as you normally have a
plastic surround on both the inside and outside to cover damage around the
hole.

Complications - as stated in another reply, make very sure that there are no
obstructions inside or out where you plan to drill.
Also check that there are no services running down the inside of the wall.
Do you have cavity wall insulation?
I don't know if this is an issue - just had a vision of loose insulation
pouting out of the hole :-(

Be careful working outside - an SDS drill can wallop a big hole in the wall
but can also hurl you off the ladder with the recoil :-)

You should be fine DIYing it - just go cautiously.

HTH
Dave R

On 27 Oct 2003 02:56:34 -0800, (Caher) wrote:

Firstly, should I drill from the inside going out or the outside
going in? And secondly are there any unforeseen complications that the
novice DIY person like me might miss and should I call a professional?

If it is a cavity wall then drill a long thin hole thru first, then
you can push the big drill thru from both sides to meet in the middle.

PoP

"PoP" wrote in message
...
On 27 Oct 2003 02:56:34 -0800, (Caher) wrote:

Firstly, should I drill from the inside going out or the outside
going in? And secondly are there any unforeseen complications that the
novice DIY person like me might miss and should I call a professional?

If it is a cavity wall then drill a long thin hole thru first, then
you can push the big drill thru from both sides to meet in the middle.

I assume you mean big drill means a core drill?

Normally you would put a pilot hole from the inside to the outside. You can
then put the fan where you want, but before you drill this hole you have to
check where the external grill is going to be. A tape measure and a few
windows and doors give a good reference point for the external grille. Also
watch out for concrete lintels. There is nothing worse than attempting to
put a fan just to the side and above a window. It will never work (been
there).
Another common mistake is to mount the fan higher than a window (in an
upstairs room) and you may find you have put the fan higher than the
soffiits (I have also been there).

HTH

--
Adam

On Mon, 27 Oct 2003 18:29:26 GMT, "ARWadsworth"
wrote:

I assume you mean big drill means a core drill?

Right. 110mm or 117mm usually.

PoP

One more question:
Where should the power wire go - between the cavity and up into the loft?
Thanks again.

On 12 Nov 2003 02:35:53 -0800, (Caher) wrote:

Where should the power wire go - between the cavity and up into the loft?

Running power cabling within the cavity is not recommended. Some of
the reasons include if the cavity is filled with insulation at some
future point in time there could be a chemical reaction between the
insulation and cable. There is also a consideration with regard to
power rating and heat transfer. Hardly likely to be a major issue with
a fan which is almost always low power (I'm assuming this fan doesn't
have a heater built in), but could be later.

The fan should be a spur from the upstairs ring main, not the lighting
circuit. And upstairs ring mains tend to come up from the floor rather
than down from the loft. Note the word "tend", you can't count on it.

So you might want to think about coming down rather than going up.

Furthermore you should have the fan fed via a fused spur which has a
3A fuse. Don't connect it directly to the ring main because it's
likely that the fan would burn out before it took the fuse (or MCB)
down. It's a low power device.

PoP

PoP wrote in message . ..

The fan should be a spur from the upstairs ring main, not the lighting
circuit. And upstairs ring mains tend to come up from the floor rather
than down from the loft. Note the word "tend", you can't count on it.

Why not from the lighting circuit? Isn't that the way to wire them if
you want them to switch on automatically with the light switch (eg as
in the case of an internal bathroom/toilet)?

David

On 12 Nov 2003 16:11:38 -0800,
(Lobster) wrote:

The fan should be a spur from the upstairs ring main, not the lighting
circuit. And upstairs ring mains tend to come up from the floor rather
than down from the loft. Note the word "tend", you can't count on it.

Why not from the lighting circuit? Isn't that the way to wire them if
you want them to switch on automatically with the light switch (eg as
in the case of an internal bathroom/toilet)?

Actually....you may be okay with this. I was coming from the direction
that "appliances" should be fed from ring circuits (or spur...), and
lights from lighting circuits. But I haven't seen anything written on
tablets of stone to advise that it has to be that way.

Not that a fan is an "appliance", but if it is generating light then I
would assume it might have a problem

PoP

Lobster wrote:
PoP wrote in message . ..

The fan should be a spur from the upstairs ring main, not the lighting
circuit. And upstairs ring mains tend to come up from the floor rather
than down from the loft. Note the word "tend", you can't count on it.

Why not from the lighting circuit? Isn't that the way to wire them if

Because Murphy's says that if it is going to fail it will do so at
night

you want them to switch on automatically with the light switch (eg as
in the case of an internal bathroom/toilet)?

In this case the fan has two live connectors. One to power the fan
and electronics and one connected to the switched live feeding the
lamp(s).

Why not from the lighting circuit? Isn't that the way to wire them if
you want them to switch on automatically with the light switch (eg as
in the case of an internal bathroom/toilet)?

Thats the way we wire them.
From the bathroom fitting we take a 3core and earth (6243Y) to a 3 pole fan
isolator (outside of the bathroom) then another 3core and earth to the fan
itself. The 3 core carries a permanent live, a switched live and a neutral.

--
Gary
Please remove #NOSPAM# if replying via email

In message ,
Mark Evans wrote:

Lobster wrote:
PoP wrote in message . ..

The fan should be a spur from the upstairs ring main, not the lighting
circuit. And upstairs ring mains tend to come up from the floor rather
than down from the loft. Note the word "tend", you can't count on it.

Why not from the lighting circuit? Isn't that the way to wire them if

Because Murphy's says that if it is going to fail it will do so at
night

you want them to switch on automatically with the light switch (eg as
in the case of an internal bathroom/toilet)?

In this case the fan has two live connectors. One to power the fan
and electronics and one connected to the switched live feeding the
lamp(s).

I would have thought that your idea is bloomin' dangerous - by
connecting the "permanent live" to the sockets and the "switched
live" to the lights the fan is in effect connected across two separately
fused circuits and a fault at the fan may not cause enough current to
flow to blow both fuses. Also consider the case where the fan actually
connects "SL" to "PL" internally, perhaps in a fault condition (who
knows what the electronics do?). In this case you have created a huge
circuit, partly wired in (usually) 2.5mm cable, partly in (usually) 1mm
cable and protected by what amounts to probably a 38A MCB (32A+6A). Not
only that, but you have bridged the two neutrals too and this could
cause big problems if, as is often the case these days even upstairs,
your sockets are wired via an RCD but your lights are not.

The only instance where I would consider spuring a typical run-on fan
from a sockets circuit would be where the fan is controlled in some way
*other* than via the light switch. It may have its own pullcord, or a
door switch, or it may be controlled by a humidity sensor or even a PIR.

Hwyl!

M.

--
Martin Angove: http://www.tridwr.demon.co.uk/
Don't fight technology, live with it: http://www.livtech.co.uk/
.... Modem, said the gardener when he'd finished the lawn..

Hi


I think these extractor fans are not a good solution anyway. Theyre
not particularly effective, theyre noisy and annoying, and the
bearings are guaranteed to deteriorate making them very noisy. And
they simply throw your heat away.

Alternatives a

HRV, which costs very little more, works like a fan but recovers most
of the heat.

A window lock enabling it to be locked 1/4" open - good, effective and
free for most of the year, but not so good for the coldest few months.

Dehumidifier - a bit more to install, much more efficient, doesnt
ventilate or lose any heat.

Finally the simplest option of all, an adjustable vent. Easy, cheap,
simple, no run cost, and effective year round.

Anything but a fan, they are just the worst option.


Regards, NT

"Martin Angove" wrote
| In this case the fan has two live connectors. One to power the fan
| and electronics and one connected to the switched live feeding the
| lamp(s).
| I would have thought that your idea is bloomin' dangerous ...
| consider the case where the fan actually connects "SL" to "PL"
| internally, perhaps in a fault condition (who knows what the
| electronics do?). In this case you have created a huge circuit,
| partly wired in (usually) 2.5mm cable, partly in (usually) 1mm
| cable and protected by what amounts to probably a 38A MCB (32A+6A).

And if the lighting circuit in the bathroom and the socket circuit borrowed
from (because there shouldn't be a socket circuit in the bathroom ...)
happen to be on different phases ....

Owain

In message ,
"Owain" wrote:

"Martin Angove" wrote
| In this case the fan has two live connectors. One to power the fan
| and electronics and one connected to the switched live feeding the
| lamp(s).
| I would have thought that your idea is bloomin' dangerous ...
| consider the case where the fan actually connects "SL" to "PL"
| internally, perhaps in a fault condition (who knows what the
| electronics do?). In this case you have created a huge circuit,
| partly wired in (usually) 2.5mm cable, partly in (usually) 1mm
| cable and protected by what amounts to probably a 38A MCB (32A+6A).

And if the lighting circuit in the bathroom and the socket circuit borrowed
from (because there shouldn't be a socket circuit in the bathroom ...)
happen to be on different phases ....



Well, yes, though this isn't often the case domestically :-) I thought
of another reason for not doing it - anyone who doesn't know the system
won't know how to isolate it, other than perhaps through the 3-pole
isolator which is supposed to be fitted these days.

I "Googled" back on the thread a bit, as the earliest post I have on my
system here is Mark Evans's on the 30th November. I notice that PoP's
original suggestion was to wire the permanent live through a 3A fused
spur... still not a good idea for all the reasons already mentioned, but
very slightly less bad than straight from the sockets circuit.

Got very confused with some "early" postings under the heading
"Extractor Fan"... it seems that this is at least the second thread on
the subject, and the previous one was in 2002 :-)

Hwyl!

M.

--
Martin Angove: http://www.tridwr.demon.co.uk/
Don't fight technology, live with it: http://www.livtech.co.uk/
.... Sometimes you just have to say 'What the heck'

"Martin Angove" wrote in message
...

I thought of another reason for not doing it - anyone who doesn't
know the system won't know how to isolate it, other than perhaps
through the 3-pole isolator which is supposed to be fitted these
days.

Another reason will become clear if you consider that the ring circuit might
be fed via an RCD and the lighting circuit not...

More fundamentally though it violates regulation 314-01-04 which says that
the wiring of final circuits must be kept electrically separate.

I can't find the beginning of this thread, but whomever it was that said:

The fan should be a spur from the upstairs ring main, not the
lighting circuit

wants locking up.

--
Andy

On Wed, 3 Dec 2003 07:53:54 -0000, "Andy Wade"
wrote:

The fan should be a spur from the upstairs ring main, not the
lighting circuit

wants locking up.

Guilty as charged

However, I don't see what you are getting at with your comment.

PoP

In message ,
"Andy Wade" wrote:

"Martin Angove" wrote in message
...

I thought of another reason for not doing it - anyone who doesn't
know the system won't know how to isolate it, other than perhaps
through the 3-pole isolator which is supposed to be fitted these
days.

Another reason will become clear if you consider that the ring circuit might
be fed via an RCD and the lighting circuit not...


I already mentioned that one in a previous reply.

More fundamentally though it violates regulation 314-01-04 which says that
the wiring of final circuits must be kept electrically separate.

And although I din't quote the regulation, I said as much in the same
one :-)

I can't find the beginning of this thread, but whomever it was that said:

The fan should be a spur from the upstairs ring main, not the
lighting circuit

wants locking up.


No, he wants educating. Someone who learns a lesson like this is more
likely to put it into practice than someone who hasn't thought about it
and blindly follows rules... or something like that... sorry, not quite
thinking straight as have had 2 hours sleep in the last 36 due to
arrival of offspring #2.

Hwyl!

M.

--
Martin Angove: http://www.tridwr.demon.co.uk/
Don't fight technology, live with it: http://www.livtech.co.uk/
.... Never take a beer to a job interview.

In message ,
PoP wrote:

On Wed, 3 Dec 2003 07:53:54 -0000, "Andy Wade"
wrote:

The fan should be a spur from the upstairs ring main, not the
lighting circuit

wants locking up.

Guilty as charged

However, I don't see what you are getting at with your comment.

Which comment? Elucidate and we will expand.

Hwyl!

M.

--
Martin Angove: http://www.tridwr.demon.co.uk/
Don't fight technology, live with it: http://www.livtech.co.uk/
.... BASIC isn't; C stands for Confusing...

On Wed, 03 Dec 2003 15:59:08 GMT, Martin Angove
wrote:

However, I don't see what you are getting at with your comment.

Which comment? Elucidate and we will expand.

Locking up.....

I was under the impression that fan circuits would be run as a spur
from the upstairs ring. I guess I'm basing that assumption on a
previous house I owned where I know that was the arrangement (and I
didn't wire that property, it must have been before the 16th ed came
out).

Could you please explain what is wrong with running a fan circuit as a
spur from the upstairs ring? I would assume from a technical
standpoint that providing it is properly fused (that is, minimum fuse
rating - 3A?) and appropriate cabling is employed then it would meet
the requirements of the 16th edition regs. Having got my 16th edition
regs certificate earlier this year I'm wondering what I've missed!

Always willing to learn....

PoP

On Wed, 03 Dec 2003 16:40:31 +0000, PoP wrote:

On Wed, 03 Dec 2003 15:59:08 GMT, Martin Angove
wrote:

However, I don't see what you are getting at with your comment.

Which comment? Elucidate and we will expand.

Locking up.....

I was under the impression that fan circuits would be run as a spur
from the upstairs ring. I guess I'm basing that assumption on a
previous house I owned where I know that was the arrangement (and I
didn't wire that property, it must have been before the 16th ed came
out).

Could you please explain what is wrong with running a fan circuit as a
spur from the upstairs ring? I would assume from a technical
standpoint that providing it is properly fused (that is, minimum fuse
rating - 3A?) and appropriate cabling is employed then it would meet
the requirements of the 16th edition regs. Having got my 16th edition
regs certificate earlier this year I'm wondering what I've missed!

Always willing to learn....

Here are two resons:
1) It mmight not be obvious to someone that supply is from the upstairs
ring rather than the downstairs lighting. Not withstanding that there
ought to be a service isolator for the fan.

2) If the fan is the sort that requires both permenent and switched live
supplies (such as timed overrun models) then you will have also to
supply switched live from two seperate circuits. Which not only is contrary
to the regs but poses hazards for maintainers and might even make two
circuts have common live connections through the fan timer circuits.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

On Wed, 03 Dec 2003 18:56:16 +0000, "Ed Sirett"
wrote:

Here are two resons:

Thanks for that Ed. I guess I've learnt from this thread

PoP

In message ,
PoP wrote:

On Wed, 03 Dec 2003 15:59:08 GMT, Martin Angove
wrote:

However, I don't see what you are getting at with your comment.

Which comment? Elucidate and we will expand.

Locking up.....

I was under the impression that fan circuits would be run as a spur
from the upstairs ring. I guess I'm basing that assumption on a
previous house I owned where I know that was the arrangement (and I
didn't wire that property, it must have been before the 16th ed came
out).

Could you please explain what is wrong with running a fan circuit as a
spur from the upstairs ring?

It wasn't that which caused the problem, it was the suggestion that
for a run-on fan you should wire the "permanent live" from such a spur,
but take the "switched live" from the (e.g. bathroom) light switch. In
this instance you have connected the fan across two circuits which
*should* be separate for all the reasons already mentioned (refer to my
previous reply).

I would assume from a technical standpoint
that providing it is properly fused (that is, minimum fuse rating - 3A?)
and appropriate cabling is employed then it would meet the requirements
of the 16th edition regs.

If the fan was, say, a stand-alone fan controlled by its own switch or
humidistat for example, then there's no problem connecting it to the
sockets circuit. In fact, especially for large fans in large kitchens
for example, there are positive benefits.

Having got my 16th edition regs certificate
earlier this year I'm wondering what I've missed!


I'm not sure you missed anything actually in the exam, except the very
small but vital point of keeping circuits separate. I took mine earlier
this year too, and don't think that was mentioned, but then a lot of
other stuff wasn't mentioned either.

Always willing to learn....


This is the kind of point which to many people seems so blindingly
obvious as not to need labouring (oh boy, after last night, do I know
about labour!) but which to the person on autopilot can quite easily
lead to a major safety issue. Again, for clarification of the possible
safety issues I refer the reader to my previous reply on the current
version of this thread :-)

HTH

Hwyl!

M.

--
Martin Angove: http://www.tridwr.demon.co.uk/
Don't fight technology, live with it: http://www.livtech.co.uk/
.... Man who eats too many prunes, sits on toilet, many moons!

On Wed, 03 Dec 2003 22:29:15 GMT, Martin Angove
wrote:

It wasn't that which caused the problem, it was the suggestion that
for a run-on fan you should wire the "permanent live" from such a spur,
but take the "switched live" from the (e.g. bathroom) light switch. In
this instance you have connected the fan across two circuits which
*should* be separate for all the reasons already mentioned (refer to my
previous reply).

Ding! Sorry, my lights have just switched on!

I certainly didn't mean it to be wired that way, and you are
absolutely right about me being locked up if that's what I
suggested.....

What I was thinking was that the fan would be standalone and not
controlled by the light switch. In our current house for example our
bathrooms have a fan which is controlled explicitly by a switch
outside of the bathroom, and I assume that this would be wired to the
ring main (switching the lights on and off has no effect on the fan).

This is the kind of point which to many people seems so blindingly
obvious as not to need labouring (oh boy, after last night, do I know
about labour!) but which to the person on autopilot can quite easily
lead to a major safety issue. Again, for clarification of the possible
safety issues I refer the reader to my previous reply on the current
version of this thread :-)

I need to take more care about expressing myself.....

PoP

In message ,
PoP wrote:

On Wed, 03 Dec 2003 22:29:15 GMT, Martin Angove
wrote:

It wasn't that which caused the problem, it was the suggestion that
for a run-on fan you should wire the "permanent live" from such a spur,
but take the "switched live" from the (e.g. bathroom) light switch. In
this instance you have connected the fan across two circuits which
*should* be separate for all the reasons already mentioned (refer to my
previous reply).

Ding! Sorry, my lights have just switched on!

I certainly didn't mean it to be wired that way, and you are
absolutely right about me being locked up if that's what I
suggested.....

What I was thinking was that the fan would be standalone and not
controlled by the light switch. In our current house for example our
bathrooms have a fan which is controlled explicitly by a switch
outside of the bathroom, and I assume that this would be wired to the
ring main (switching the lights on and off has no effect on the fan).

This is the kind of point which to many people seems so blindingly
obvious as not to need labouring (oh boy, after last night, do I know
about labour!) but which to the person on autopilot can quite easily
lead to a major safety issue. Again, for clarification of the possible
safety issues I refer the reader to my previous reply on the current
version of this thread :-)

I need to take more care about expressing myself.....


Well, actually I don't think it was you who caused the problem, it was
the selective quoting of Mark Evans. Watch the quoting below:

Mark Evans wrote:
Lobster wrote:
PoP wrote:

[in relation to a question about whether to run power cable for a
bathroom fan down inside the cavity...]

The fan should be a spur from the upstairs ring main, not the lighting
circuit. And upstairs ring mains tend to come up from the floor rather
than down from the loft. Note the word "tend", you can't count on it.

Why not from the lighting circuit? Isn't that the way to wire them if

Because Murphy's says that if it is going to fail it will do so at
night

you want them to switch on automatically with the light switch (eg as
in the case of an internal bathroom/toilet)?

In this case the fan has two live connectors. One to power the fan
and electronics and one connected to the switched live feeding the
lamp(s).

See what I mean?

HTH

Hwyl!

M.

--
Martin Angove: http://www.tridwr.demon.co.uk/
Don't fight technology, live with it: http://www.livtech.co.uk/
.... Does history record any case where a majority was right?

On Thu, 04 Dec 2003 23:05:10 GMT, Martin Angove
wrote:

See what I mean?

Yup.

PoP

"Martin Angove" wrote in message
...

[cross-connecting ccts, RCDs]

I already mentioned that one in a previous reply.

Yes, sorry, I dived into a thread in which, for some reason, most of the
articles weren't visible. Mind you IME of fans with switched live
terminals, which is confined to one model (Vent Axia VA100H), the current
drawn via the SL is minuscule (a few hundred uA). SL just feeds some
electronics which drives the gate of a triac in the main fan motor cct, so
the motor current is always taken from the permanant live terminal. Other
designs may be quite different

wants locking up.
No, he wants educating.

Of course - which now seems to have happened.

thinking straight as have had 2 hours sleep in the last 36 due to
arrival of offspring #2.

Congratulations.

--
Andy

In message ,
"Andy Wade" wrote:

"Martin Angove" wrote in message
...

[cross-connecting ccts, RCDs]

I already mentioned that one in a previous reply.

Yes, sorry, I dived into a thread in which, for some reason, most of the
articles weren't visible.

I had the same problem which is why I went off to Google - they seemed
to have the lot. Clara and Demon don't share a newsfeed, do they?

Mind you IME of fans with switched live terminals, which is confined to one
model (Vent Axia VA100H), the current drawn via the SL is minuscule (a few
hundred uA). SL just feeds some electronics which drives the gate of a triac
in the main fan motor cct, so the motor current is always taken from the
permanant live terminal. Other designs may be quite different


That is the way I'd design it, and isn't really a problem. The problem
is that, whatever the actual current drawn, power from (as suggested)
two otherwise completely separate circuits is present on the same
circuit board, probably in adjacent tracks from the connecting block.
There is no guarantee that these tracks have 500V worth of insuation
between them. Likewise there is no guarantee that any switching device
(a triac is certainly a possibility) will not connect the "switch" and
"load" sides of itself in a failure mode, or for that matter under
normal conditions.

If such a connection absolutely must be made than the most obvious way
I can think of to do it would be some kind of relay with two operating
coils, one for "switch" and the other held on via a timer from "load".
I doubt any fan manufacturer would do this when they can get away with
a triac and an RC timer :-)

wants locking up.
No, he wants educating.

Of course - which now seems to have happened.


Well, we haven't actually heard from Mark Evans. ISTM that PoP knew what
he was talking about, didn't quite write it down clearly enough and was
then selectively quoted by Mark...

thinking straight as have had 2 hours sleep in the last 36 due to
arrival of offspring #2.

Congratulations.


Thanks! All home the same day and settling into routines again... not
much more sleep though :-/

Hwyl!

M.

--
Martin Angove: http://www.tridwr.demon.co.uk/
Don't fight technology, live with it: http://www.livtech.co.uk/
.... If at first you don't succeed, destroy all evidence that you tried.