Can someone tell me whether it's recommended or mandatory to install a
double pole isolator switch on a bathroom extractor fan? If mandatory I
presume anywhere other than z1 or z2 is OK?

--
Dave S
(The return email address is a dummy)

Dave wrote:
Can someone tell me whether it's recommended or mandatory to install a
double pole isolator switch on a bathroom extractor fan? If mandatory I
presume anywhere other than z1 or z2 is OK?


Certainly mandatory if it has any form of overrun (timer, humidistat
etc) but AFAIK there's some disagreement as to whether it's needed if
the fan is controlled only from a normal switch, on it's own (ie with no
source of power from anywhere else). I fitted one like this during a
recent rewire and asked the sparks who was going to be testing my
wiring, and he said the DP isolator wasn't needed then.

Others will be along shortly to disagree with this!

David

Dave wrote:
Can someone tell me whether it's recommended or mandatory to install a
double pole isolator switch on a bathroom extractor fan? If mandatory I
presume anywhere other than z1 or z2 is OK?

I'd say, "a good enough idea that you should do it".

Pinhead-dancing angels would go into the subtelties of isolation vs
functional switching vs switching-for-maintenance and so on.

"Dave" wrote in message
...
Can someone tell me whether it's recommended or mandatory to install a
double pole isolator switch on a bathroom extractor fan? If mandatory I
presume anywhere other than z1 or z2 is OK?

--
Dave S
(The return email address is a dummy)

It is recommended but not mandatory, most rented accommodation I visit don't
have and they have passed an electrical inspection.

If you do put one in why not leave it in the loft if you have access.

Dave Jones

It is recommended but not mandatory, most rented accommodation I visit
don't have and they have passed an electrical inspection.

If you do put one in why not leave it in the loft if you have access.

I wish I had read this prior to cutting out a space for a recessed box to
fit an isolation switch to

Dave Jones

John Borman wrote:

I wish I had read this prior to cutting out a space for a recessed box to
fit an isolation switch to

Instead, you should be glad that you had not read the very bad advice
just given and have done the job properly.

Above all a fan isolator (3-pole, BTW, if the fan takes a switched live
control feed from the bathroom light) is required to comply with Reg.
131-14-02: "Every fixed electric motor shall be provided with an
efficient means of switching off, readily accessible, easily operated
and so placed as to prevent danger."

Putting the switch in the loft is not an acceptable option, any more
than than is hiding appliance control switches in kitchen cupboards.
These things are meant to be accessible.

--
Andy

On Wed, 29 Dec 2004 16:21:13 GMT, Lobster
strung together this:

Dave wrote:
Can someone tell me whether it's recommended or mandatory to install a
double pole isolator switch on a bathroom extractor fan? If mandatory I
presume anywhere other than z1 or z2 is OK?


Certainly mandatory if it has any form of overrun (timer, humidistat
etc) but AFAIK there's some disagreement as to whether it's needed if
the fan is controlled only from a normal switch, on it's own (ie with no
source of power from anywhere else).


You mean battery powered? If you have no external source of power then
it needs an isolator. If the fan requires an isolator when it is a
timer model that's because it is a fixed appliance. If it is a
non-timer model it's still a fan, so needs an isolator.

When is a fan not a fan?
Never.

I fitted one like this during a
recent rewire and asked the sparks who was going to be testing my
wiring, and he said the DP isolator wasn't needed then.

He wants sacking.

Others will be along shortly to disagree with this!

Yep, I'm sure they will. ;-)
--

SJW
Please reply to group or use 'usenet' in email subject

On Wed, 29 Dec 2004 19:25:02 -0000, "John Borman"
strung together this:

It is recommended but not mandatory,

It's mandatory, if you're going to do it do it properly.

most rented accommodation I visit
don't have and they have passed an electrical inspection.

No they haven't, they've been tested by someone who doesn't know what
they're doing.

If you do put one in why not leave it in the loft if you have access.

I wish I had read this prior to cutting out a space for a recessed box to
fit an isolation switch to

Well, that would be wrong. Don't believe everything you read on
usenet. If the fan is in the bathroom then it is no good putting the
isolator in the loft. It should be reasonaly local to the appliance
it's controlling unless it's lockable in the off position.
--

SJW
Please reply to group or use 'usenet' in email subject

On Thu, 30 Dec 2004 00:54:12 +0000, Andy Wade
wrote:

Putting the switch in the loft is not an acceptable option,

It may acceptable, and indeed appropriate. To reduce noise, many such
fans are loft mounted rather than being part of their inlet plate. So
long as the switch is accessible from the sensible access route to the
motor, then there's no problem with loft mounting it.

--
Smert' spamionam

"Lurch" wrote in message
...
On Wed, 29 Dec 2004 19:25:02 -0000, "John Borman"
strung together this:

It is recommended but not mandatory,

It's mandatory, if you're going to do it do it properly.

most rented accommodation I visit
don't have and they have passed an electrical inspection.

No they haven't, they've been tested by someone who doesn't know what
they're doing.

snip
110-04-01 The Regulations are non-statutory. .....

i.e. NOT mandatory

They have passed an electrical inspection, wether the person was competent
or not is another thing.

I did say if you have access, a loft with a loft ladder or other means,
would be more suitable than a switch located on a 9 ft ceiling, where by you
have to use a ladder/chair in order to use it.

"Every fixed electric motor shall be provided with an efficient means of
switching off, readily accessible, easily operated and so placed as to
prevent danger."

So with that in mind an isolating switch could be placed any where within a
reasonable distance of the fan, either inside or outside the bathroom,
providing you have access.

Dave Jones wrote:

I did say if you have access, a loft with a loft ladder or other means,
would be more suitable than a switch located on a 9 ft ceiling, where by you
have to use a ladder/chair in order to use it.

Try one of these:-

http://www.tlc-direct.co.uk/Products/ASCS3PIF.html

So with that in mind an isolating switch could be placed any where within a
reasonable distance of the fan, either inside or outside the bathroom,
providing you have access.

You can go for a switch outside the bathroom if you prefer.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

Lurch wrote:
On Wed, 29 Dec 2004 16:21:13 GMT, Lobster
strung together this:

Dave wrote:

Can someone tell me whether it's recommended or mandatory to install a
double pole isolator switch on a bathroom extractor fan? If mandatory I
presume anywhere other than z1 or z2 is OK?


Certainly mandatory if it has any form of overrun (timer, humidistat
etc) but AFAIK there's some disagreement as to whether it's needed if
the fan is controlled only from a normal switch, on it's own (ie with no
source of power from anywhere else).

You mean battery powered? If you have no external source of power then
it needs an isolator. If the fan requires an isolator when it is a
timer model that's because it is a fixed appliance. If it is a
non-timer model it's still a fan, so needs an isolator.

No, mains; I was making the distinction between a fan which receives its
power via a single source, ie, through a wall switch or pull-cord
switch, and one which has a second live feed as in the case of a fan
wired to come on and off with the bathroom light, but with provision for
overrun after the light has been switched off.

When is a fan not a fan?
Never.

I fitted one like this during a
recent rewire and asked the sparks who was going to be testing my
wiring, and he said the DP isolator wasn't needed then.

He wants sacking.

But you must admit there's a fundamental difference in the two different
types of fan described above, surely? The whole point of having an
isolator on a fan is so it can be properly switched off for maintainence
while the light is switched on, yes? Common sense says that's not
necessary if the fan is already wired through its own, dedicated switch.
If you're going to insist that such a fan needs an isolator too, then
why not insist that each and every light fitting has one, too?

David

On Thu, 30 Dec 2004 11:54:08 GMT, Lobster
strung together this:

No, mains; I was making the distinction between a fan which receives its
power via a single source, ie, through a wall switch or pull-cord
switch, and one which has a second live feed as in the case of a fan
wired to come on and off with the bathroom light, but with provision for
overrun after the light has been switched off.

But you must admit there's a fundamental difference in the two different
types of fan described above, surely?

No, a fan is a fan.

The whole point of having an
isolator on a fan is so it can be properly switched off for maintainence
while the light is switched on, yes?

No, the point in having the isolator is so that it can be isolated for
maintenance, irrespective of the lighting in the room or the
appliances method of connection.

Common sense says that's not
necessary if the fan is already wired through its own, dedicated switch.

You're getting two terms mixed up here.
An isolator isolates all live cables for maintenance purposes, i.e.
live and neutral supplies switched or not.
A switch switches in the live wire to the appliance, therefore it
isn't an isolator, it is a functional switch to turn the appliance on
and off.

If you're going to insist that such a fan needs an isolator too, then
why not insist that each and every light fitting has one, too?

I'm not insisting, BS7671 is insisting. As we're all meant to be
working to that standard what are you getting at me for?
A fan is a fixed appliance, a fixed appliance needs an isolator. How
clearer do you want it?
--

SJW
Please reply to group or use 'usenet' in email subject

On Thu, 30 Dec 2004 09:31:40 -0000, "Dave Jones"
strung together this:

I did say if you have access, a loft with a loft ladder or other means,
would be more suitable than a switch located on a 9 ft ceiling, where by you
have to use a ladder/chair in order to use it.

That's why pull switches were invented, or put it lower down the wall.
--

SJW
Please reply to group or use 'usenet' in email subject

Andy Dingley wrote:
On Thu, 30 Dec 2004 00:54:12 +0000, Andy Wade
wrote:
Putting the switch in the loft is not an acceptable option,

It may acceptable, and indeed appropriate. To reduce noise, many such
fans are loft mounted rather than being part of their inlet plate. So
long as the switch is accessible from the sensible access route to the
motor, then there's no problem with loft mounting it.

OK & agreed. I was talking about the case where the fan motor is in the
bathroom.

--
Andy

I'm not insisting, BS7671 is insisting. As we're all meant to be
working to that standard what are you getting at me for?
A fan is a fixed appliance, a fixed appliance needs an isolator. How
clearer do you want it?
--


I agree been thro this before with built in kitchen appliances needing a
isolator how simple can it be ?

Peter

I'm not insisting, BS7671 is insisting. As we're all meant to be
working to that standard what are you getting at me for?
A fan is a fixed appliance, a fixed appliance needs an isolator. How
clearer do you want it?


One question though - how come a lightbulb isn't a fixed appliance ?

"Mike" wrote in message
...


I'm not insisting, BS7671 is insisting. As we're all meant to be
working to that standard what are you getting at me for?
A fan is a fixed appliance, a fixed appliance needs an isolator. How
clearer do you want it?


One question though - how come a lightbulb isn't a fixed appliance ?


Because it is simple to un-plug it from its holder. A fixed appliance is
one which is connected directly to a supply source with connections that
need a tool to be able to remove it. In this case, your hand is not classed
as a tool.

Mike wrote:

One question though - how come a lightbulb isn't a fixed appliance ?

It is - or rather a luminaire is fixed equipment. Isolation
requirements for the circuit are met at the consumer unit by way of an
MCB and/or main switch with provision for locking-off. The additional
specific requirements for a fan arise because of the presence of a
motor. [See pp. 34-35 in the OSG.]

BTW isolators don't, in general, have to be double-pole, except in
TT-earthed installations, and except for the main switch(es) of a
single-phase domestic installation. (In 3-phase installations it's very
common practice for isolators to be 3-pole with a solid removable
neutral link.)

--
Andy

"BigWallop" wrote in message
. ..

"Mike" wrote in message
...


I'm not insisting, BS7671 is insisting. As we're all meant to be
working to that standard what are you getting at me for?
A fan is a fixed appliance, a fixed appliance needs an isolator. How
clearer do you want it?


One question though - how come a lightbulb isn't a fixed appliance ?


Because it is simple to un-plug it from its holder.

Whereupon it's easy to touch neutral for an ES holder. So why aren't light
switches double pole ?

"Mike" wrote in message
...

"BigWallop" wrote in message
. ..

"Mike" wrote in message
...


I'm not insisting, BS7671 is insisting. As we're all meant to be
working to that standard what are you getting at me for?
A fan is a fixed appliance, a fixed appliance needs an isolator.
How
clearer do you want it?


One question though - how come a lightbulb isn't a fixed appliance ?


Because it is simple to un-plug it from its holder.

Whereupon it's easy to touch neutral for an ES holder. So why aren't
light
switches double pole ?



The neutral is more likely to be at, or very very close to, the same
potential as earth. So why should the switch need to be double pole?

Mike wrote:


Whereupon it's easy to touch neutral for an ES holder. So why aren't light
switches double pole ?

Letter-of-the-regs answer: because they're specifically exempted!

Why-we-don't-all-die answer: ES holders where the outer screw is
all-metal are dinosaur objects - nothing that's been on general retail
sale for domestic use has had the all-metal-outer-screw construction for
20+ years. The construction that's replaced it has a plastic or ceramic
thread, with a spring contact some way down which makes contact with the
ES blub's screw-in base. Arguably, the two contacts on such an ES holder
are a little less likely to be touched than the two pins of the British
Bayonet.

Yes, halide; yes, stage lighting fittings. I did say "domestic use".

And again in th'domestic case, most people who want to get on with life
switch off before changing a bulb, and avoid poking their fingers in
anyway; and are rarely in low-resistance contact with earth should they
make inadverdent contact anyway.

But hey, if you want to get double-pole switching for lighting circuits
written into 17th Edn Regs, campaign away...

Following up to last week's thread.


On Thu, 30 Dec 2004 09:31:40 -0000, "Dave Jones"
wrote:


"Lurch" wrote in message
.. .
On Wed, 29 Dec 2004 19:25:02 -0000, "John Borman"
strung together this:

It is recommended but not mandatory,

It's mandatory, if you're going to do it do it properly.

most rented accommodation I visit
don't have and they have passed an electrical inspection.

No they haven't, they've been tested by someone who doesn't know what
they're doing.

snip
110-04-01 The Regulations are non-statutory. .....

i.e. NOT mandatory

They have passed an electrical inspection, wether the person was competent
or not is another thing.

I did say if you have access, a loft with a loft ladder or other means,
would be more suitable than a switch located on a 9 ft ceiling, where by you
have to use a ladder/chair in order to use it.

"Every fixed electric motor shall be provided with an efficient means of
switching off, readily accessible, easily operated and so placed as to
prevent danger."


A "Bathroom Fan" is not a "Fixed Electric Motor".

It strikes me that I've never seen a bathroom fan with it's own isolator
in any of the (what seems like millions of) hotel/lodge bathrooms I've
used, which almost universally have a fan controlled via a run on timer
operating off the light switch. In fact I've never seen such a fan with
a dedicated isolator switch at all, an occasional fused spur, possibly.

Clearly this regulation was intended to apply to bigger, more powerful
electric motors which constitute a seperate installation in themselves,
with the intention of ensuring it is possible to reliably isolate it for
maintenance of the motor and the machinery it drives, or in an
emergency.

There is a difference between an 8 watt motor inside a "loovent" and a 5
horsepower "Fixed Electric Motor" driving a workshop full of machine
tools through shafting and belting.

Or am I wrong?

DG

"Derek *" wrote in message
...

Following up to last week's thread.


On Thu, 30 Dec 2004 09:31:40 -0000, "Dave Jones"
wrote:


"Lurch" wrote in message
.. .
On Wed, 29 Dec 2004 19:25:02 -0000, "John Borman"
strung together this:

It is recommended but not mandatory,

It's mandatory, if you're going to do it do it properly.

most rented accommodation I visit
don't have and they have passed an electrical inspection.

No they haven't, they've been tested by someone who doesn't know what
they're doing.

snip
110-04-01 The Regulations are non-statutory. .....

i.e. NOT mandatory

They have passed an electrical inspection, wether the person was
competent
or not is another thing.

I did say if you have access, a loft with a loft ladder or other means,
would be more suitable than a switch located on a 9 ft ceiling, where by
you
have to use a ladder/chair in order to use it.

"Every fixed electric motor shall be provided with an efficient means of
switching off, readily accessible, easily operated and so placed as to
prevent danger."


A "Bathroom Fan" is not a "Fixed Electric Motor".

It strikes me that I've never seen a bathroom fan with it's own isolator
in any of the (what seems like millions of) hotel/lodge bathrooms I've
used, which almost universally have a fan controlled via a run on timer
operating off the light switch. In fact I've never seen such a fan with
a dedicated isolator switch at all, an occasional fused spur, possibly.

Clearly this regulation was intended to apply to bigger, more powerful
electric motors which constitute a seperate installation in themselves,
with the intention of ensuring it is possible to reliably isolate it for
maintenance of the motor and the machinery it drives, or in an
emergency.

There is a difference between an 8 watt motor inside a "loovent" and a 5
horsepower "Fixed Electric Motor" driving a workshop full of machine
tools through shafting and belting.

Or am I wrong?

DG


You're wrong.

On Mon, 03 Jan 2005 15:13:04 +0000, Derek *
strung together this:

A "Bathroom Fan" is not a "Fixed Electric Motor".

What is it then?

It strikes me that I've never seen a bathroom fan with it's own isolator
in any of the (what seems like millions of) hotel/lodge bathrooms I've
used, which almost universally have a fan controlled via a run on timer
operating off the light switch. In fact I've never seen such a fan with
a dedicated isolator switch at all, an occasional fused spur, possibly.

Right then, several reasons why this could be.

The wiring could be wrong.
The isolator could be hidden from direct view to stop people turning
it off.
The isolator could be a lockable one in a remote location.
The fan could be fitted in a void somewhere, in which case it would
have an isolator local to it.

Clearly this regulation was intended to apply to bigger, more powerful
electric motors which constitute a seperate installation in themselves,
with the intention of ensuring it is possible to reliably isolate it for
maintenance of the motor and the machinery it drives, or in an
emergency.

No, when you say clearly you mean you have no idea so you're making it
up as you go along.

There is a difference between an 8 watt motor inside a "loovent" and a 5
horsepower "Fixed Electric Motor" driving a workshop full of machine
tools through shafting and belting.

There is in physicsl size, but not in the way the isolator rules apply
to them as they are bioth fixed electric motors.

Or am I wrong?

Yes, you're guessing and assuming. You haven't a clue so please please
please don't touch anything electrical in the future.
--

SJW
Please reply to group or use 'usenet' in email subject