Hi

My rewiring project has now reached the bathroom (qv post on halogen
lights yesterday!), into which I am now installing a ceiling-mounted
extractor fan. Bathroom is fully internal, so the fan needs an
overrun timer. I'm planning on wiring it to a 2G2W switch on the
landing, so that the light and fan come on simultaneously (the other
half of the switch being for the landing light).

Having just googled through the archives here, there seem to be
different schools of thought as to whether I can wire my fan directly
into the lighting circuit, ie in parallel with the bathroom light, or
whether it needs to go through an FCU or indeed a separate three-pole
switch (I'd rather not but want t to be legal). Can anybody enlighten
me with The Truth? (The lighting circuit will be wired to an MCB in
the consumer unit by the way.)

Cheers
David

"Lobster" wrote
| Bathroom is fully internal, so the fan needs an
| overrun timer.
| Having just googled through the archives here, there seem to be
| different schools of thought as to whether I can wire my fan directly
| into the lighting circuit, ie in parallel with the bathroom light, or
| whether it needs to go through an FCU or indeed a separate three-pole
| switch (I'd rather not but want t to be legal). Can anybody enlighten
| me with The Truth? (The lighting circuit will be wired to an MCB in
| the consumer unit by the way.)

1. As the bathroom is internal, the fan must be linked with the light and as
you say an over-run will be required.

2. Item 1 means the fan and the light must be on the same circuit.

3. If you wire it off the lighting circuit you don't need an FCU, as the
lighting circuit MCB at 6A will provide sufficient protection.

4. You do require 3-pole isolator for mechanical maintenance (so you can
clean the inside of the fan with the room light on and without mashing your
fingers). The isolator doesn't have to be in the bathroom or 'under the
control' of anybody working on the fan provided it can be locked off. The MK
one from TLC IIRC is supplied with the lock-off adapter enabling it to be
padlocked off preventing inadvertent reengergisation.
http://www.tlc-direct.co.uk/Products/MKK4857.html

Owain

In uk.d-i-y, Lobster wrote:

Having just googled through the archives here, there seem to be
different schools of thought as to whether I can wire my fan directly
into the lighting circuit,

You've said your fan needs to overrun: that means it'll need four conductors
in its supply cable[1] - a permanent live, so that the fan has its own source
of volts to run on, a "switched live" or "trigger", which is the one you
connect to the lamp's live terminal (or, equivalently, the switched-live
side of the lightswitch), and the usual neutral and earth. Because there
are two sources of Liveness (the perm-live and the trigger), in order to
isolate the fan for maintenance, you pass all three of the non-earth
conductors (that's both lives and the neutral) through their own pole
of the customary 3-pole Fan Isolating Switch. (No missing that one out,
please, as it's utterly instinctive - especially with an all-internal,
i.e. dark - bog for anyone coming in to turn on the light, even if you've
put a foldedup stepladder across the door, put a big cardboard notice
saying YOUR OLD FELLA AT WORK DO NOT COME IN on it, and are 'obviously'
doing 'Something With The Electrics'. Said instinct-follower will nevertheless
pull the lightswitch on as they stumble into the folded-up steps muttering
"who left those there, I could've tripped and hurt myself", passing two
hundred and forty gloriously alternating and energetic volts to the fan
assembly you're just adjusting the timer on with a screwdriver bit from
your hex set held directly in your fingers cos you can't be arsed stepping
down from the bog seat to get the driver handle. Worst of all, as you fall
(the shock won't be fatal, but enough to spasm you off balance) you'll
crack the porcelain cistern and make a luvverly wet mess on the bathroom
floor, and it'll seep through the kitchen ceiling below).

So, a 3-pole isolator - yes. But no need for an FCU of any sort - the
6A MCB in the lighting circuit provides overcurrent and short-circuit
protection for the fan and its cabling already.

HTH - Stefek

[1] Easiest place to pick up all 4 is in the ceiling rose for your bathroom
light, if it's a loop-in rose; if it only has the switched live, though,
you'll need a sheathed single-core, or a normal 1mm T&E with the black core
unused, to run from a suitable same-lighting-circuit perm-live to the
fan isolator switch.

In article , owain41276
@stirlingcity.co.uk says...

3. If you wire it off the lighting circuit you don't need an FCU, as the
lighting circuit MCB at 6A will provide sufficient protection.

The fan I've just fitted specifically requires a 3A fuse so an FCU is
required...

Peter

"Peter Watson" wrote
| Owain wrote
| 3. If you wire it off the lighting circuit you don't need an
| FCU, as the lighting circuit MCB at 6A will provide sufficient
| protection.
| The fan I've just fitted specifically requires a 3A fuse so an
| FCU is required...

Is that not in contradistinction to a 13A fuse /if/ an FCU is used?

Owain

"Owain" wrote in message ...
"Lobster" wrote
| Bathroom is fully internal, so the fan needs an
| overrun timer.
| Having just googled through the archives here, there seem to be
| different schools of thought as to whether I can wire my fan directly
| into the lighting circuit, ie in parallel with the bathroom light, or
| whether it needs to go through an FCU or indeed a separate three-pole
| switch (I'd rather not but want t to be legal). Can anybody enlighten
| me with The Truth? (The lighting circuit will be wired to an MCB in
| the consumer unit by the way.)

1. As the bathroom is internal, the fan must be linked with the light and as
you say an over-run will be required.

2. Item 1 means the fan and the light must be on the same circuit.

3. If you wire it off the lighting circuit you don't need an FCU, as the
lighting circuit MCB at 6A will provide sufficient protection.

4. You do require 3-pole isolator for mechanical maintenance (so you can
clean the inside of the fan with the room light on and without mashing your
fingers). The isolator doesn't have to be in the bathroom or 'under the
control' of anybody working on the fan provided it can be locked off. The MK
one from TLC IIRC is supplied with the lock-off adapter enabling it to be
padlocked off preventing inadvertent reengergisation.
http://www.tlc-direct.co.uk/Products/MKK4857.html

Thanks for both the highly enlightening - and Stefek, entertaining! -
replies! All clear now.

One point - where is it usual to position the isolator switch?
Presumably not within the bathroom? Just inside the loft access hatch
maybe? Or perhaps at ceiling height out on the landing?

Thanks
David

On Tue, 16 Mar 2004 20:38:16 -0000, in uk.d-i-y "Owain"
strung together this:

"Peter Watson" wrote
| Owain wrote
| 3. If you wire it off the lighting circuit you don't need an
| FCU, as the lighting circuit MCB at 6A will provide sufficient
| protection.
| The fan I've just fitted specifically requires a 3A fuse so an
| FCU is required...

Is that not in contradistinction to a 13A fuse /if/ an FCU is used?

What? WTF's contradistinction. What's the rest of the sentence mean?
--

SJW
A.C.S. Ltd.

Lobster wrote:

"Owain" wrote in message ...

"Lobster" wrote
| Bathroom is fully internal, so the fan needs an
| overrun timer.
| Having just googled through the archives here, there seem to be
| different schools of thought as to whether I can wire my fan directly
| into the lighting circuit, ie in parallel with the bathroom light, or
| whether it needs to go through an FCU or indeed a separate three-pole
| switch (I'd rather not but want t to be legal). Can anybody enlighten
| me with The Truth? (The lighting circuit will be wired to an MCB in
| the consumer unit by the way.)

1. As the bathroom is internal, the fan must be linked with the light and as
you say an over-run will be required.

2. Item 1 means the fan and the light must be on the same circuit.

3. If you wire it off the lighting circuit you don't need an FCU, as the
lighting circuit MCB at 6A will provide sufficient protection.

4. You do require 3-pole isolator for mechanical maintenance (so you can
clean the inside of the fan with the room light on and without mashing your
fingers). The isolator doesn't have to be in the bathroom or 'under the
control' of anybody working on the fan provided it can be locked off. The MK
one from TLC IIRC is supplied with the lock-off adapter enabling it to be
padlocked off preventing inadvertent reengergisation.
http://www.tlc-direct.co.uk/Products/MKK4857.html


Thanks for both the highly enlightening - and Stefek, entertaining! -
replies! All clear now.

One point - where is it usual to position the isolator switch?
Presumably not within the bathroom? Just inside the loft access hatch
maybe? Or perhaps at ceiling height out on the landing?


The latter, conventionally. For some reason its th only switch in the
house not statutorally placed withing wheelchair access height.



Thanks
David

On Tue, 16 Mar 2004 23:17:50 +0000, in uk.d-i-y The Natural
Philosopher strung together this:

The latter, conventionally. For some reason its th only switch in the
house not statutorally placed withing wheelchair access height.

I think that's because the likelihood of someone in a wheelchair
attempting to repair a ceiling mounted fan is slim at best. If you can
reach the ceiling you can reach the isolator.
--

SJW
A.C.S. Ltd.

The Natural Philosopher wrote in message ...
Lobster wrote:
One point - where is it usual to position the isolator switch?
Presumably not within the bathroom? Just inside the loft access hatch
maybe? Or perhaps at ceiling height out on the landing?


The latter, conventionally. For some reason its th only switch in the
house not statutorally placed withing wheelchair access height.

Thanks.

Regarding this wheelchair height stuff... if you're rewiring an old
house, which belongs to you, are you compelled to follow this rule?
Is this something that building control will kick off about when they
check other aspects of the property (I'm not informing them about the
rewiring). Or when I get the wiring signed off by a Qualified
Competent Electrician, is he likely to turn up his nose? Or when I
come to sell the property (which would in no way suit anybody in a
wheelchair anyway), what then?

David

On 17 Mar 2004 06:31:50 -0800, in uk.d-i-y
(Lobster) strung together this:

The Natural Philosopher wrote in message ...
Lobster wrote:
One point - where is it usual to position the isolator switch?
Presumably not within the bathroom? Just inside the loft access hatch
maybe? Or perhaps at ceiling height out on the landing?


The latter, conventionally. For some reason its th only switch in the
house not statutorally placed withing wheelchair access height.

Thanks.

Regarding this wheelchair height stuff... if you're rewiring an old
house, which belongs to you, are you compelled to follow this rule?
Is this something that building control will kick off about when they
check other aspects of the property (I'm not informing them about the
rewiring). Or when I get the wiring signed off by a Qualified
Competent Electrician, is he likely to turn up his nose? Or when I
come to sell the property (which would in no way suit anybody in a
wheelchair anyway), what then?

I think my post covered it. The likelihood of someone in a wheelchair
needing to isolate the fan for maintenance is highly unlikely. Even at
ceiling height the isolator is lower than a ceiling mounted fan. A
person in a wheelchair also couldn't reach the bulb in a pendant, you
don't see anyone getting in a strop over that one.
You're looking into this political correctness lark a bit too much
here. Stop making life hard for yourself.
--

SJW
A.C.S. Ltd.

On Thu, 18 Mar 2004 18:41:52 -0000, in uk.d-i-y "Lobster"
strung together this:

Regarding this wheelchair height stuff... if you're rewiring an old
house, which belongs to you, are you compelled to follow this rule?
Is this something that building control will kick off about when they
check other aspects of the property (I'm not informing them about the
rewiring). Or when I get the wiring signed off by a Qualified
Competent Electrician, is he likely to turn up his nose? Or when I
come to sell the property (which would in no way suit anybody in a
wheelchair anyway), what then?

I think my post covered it. The likelihood of someone in a wheelchair
needing to isolate the fan for maintenance is highly unlikely. Even at
ceiling height the isolator is lower than a ceiling mounted fan. A
person in a wheelchair also couldn't reach the bulb in a pendant, you
don't see anyone getting in a strop over that one.
You're looking into this political correctness lark a bit too much
here. Stop making life hard for yourself.

Sorry, I wasn't clear - I'm certainly not agonising that much over the
position of the isolator switch! I was actually meaning the rest of the
switches in the house, ie the light switches, which is what NatPhil was
alluding to.
David

Ah, gotcha now. On all the recent sites I've been on the architect has
specified switch and socket heights of between 350mm and 1200mm,
assumingly numbers lifted from the building regs. Depending on how
knowledgable\awake\bothered your BCO is on the day of the inspection
depends whether he'll pull you up on it, but doubtful if it's a refurb
of your own house. The same goes for any electrician testing the
installation also.
--

SJW
A.C.S. Ltd.

(Lurch) wrote in message ...
On Tue, 16 Mar 2004 23:17:50 +0000, in uk.d-i-y The Natural
Philosopher strung together this:

The latter, conventionally. For some reason its th only switch in the
house not statutorally placed withing wheelchair access height.

I think that's because the likelihood of someone in a wheelchair
attempting to repair a ceiling mounted fan is slim at best. If you can
reach the ceiling you can reach the isolator.

But what if they're using one of those segway stand up wheelchairs
that I saw on telly recently?

MBQ

"Lurch" wrote in message
...
On 17 Mar 2004 06:31:50 -0800, in uk.d-i-y
(Lobster) strung together this:

The Natural Philosopher wrote in message
...
Lobster wrote:
One point - where is it usual to position the isolator switch?
Presumably not within the bathroom? Just inside the loft access
hatch
maybe? Or perhaps at ceiling height out on the landing?


The latter, conventionally. For some reason its th only switch in the
house not statutorally placed withing wheelchair access height.

Thanks.

Regarding this wheelchair height stuff... if you're rewiring an old
house, which belongs to you, are you compelled to follow this rule?
Is this something that building control will kick off about when they
check other aspects of the property (I'm not informing them about the
rewiring). Or when I get the wiring signed off by a Qualified
Competent Electrician, is he likely to turn up his nose? Or when I
come to sell the property (which would in no way suit anybody in a
wheelchair anyway), what then?

I think my post covered it. The likelihood of someone in a wheelchair
needing to isolate the fan for maintenance is highly unlikely. Even at
ceiling height the isolator is lower than a ceiling mounted fan. A
person in a wheelchair also couldn't reach the bulb in a pendant, you
don't see anyone getting in a strop over that one.
You're looking into this political correctness lark a bit too much
here. Stop making life hard for yourself.

Sorry, I wasn't clear - I'm certainly not agonising that much over the
position of the isolator switch! I was actually meaning the rest of the
switches in the house, ie the light switches, which is what NatPhil was
alluding to.
David

On 18 Mar 2004 05:32:14 -0800, in uk.d-i-y
(MBQ) strung together this:

(Lurch) wrote in message ...
On Tue, 16 Mar 2004 23:17:50 +0000, in uk.d-i-y The Natural
Philosopher strung together this:

The latter, conventionally. For some reason its th only switch in the
house not statutorally placed withing wheelchair access height.

I think that's because the likelihood of someone in a wheelchair
attempting to repair a ceiling mounted fan is slim at best. If you can
reach the ceiling you can reach the isolator.

But what if they're using one of those segway stand up wheelchairs
that I saw on telly recently?

I have absolutely no idea what one of those is. But if they can reach
one, they can reach the other, just about, probably...
--

SJW
A.C.S. Ltd.