This is as much a "how to do it neatly with minimum junction boxes" as
it is about how the rules apply, but here goes anyway...

We are installing a new toilet cubicle downstairs for my M-I-L who is
finding stairs increasingly difficult. It's in the corner of what is
to become her downstairs bedroom. So far so good! :-)

To avoid chasing new channels in the (very hard) walls I'm using two
Quinetic switches, one for the main bedroom light and the other for
the toilet light which will also run the extract fan.

I have (reasonable but not *easy*, it's in the eaves) access to the
existing 6A MCB protected mains feed for the downstairs lighting above
the bedroom and toilet cubicle.

I'm using a Quinetic 'double' lighting receiver to handle the two
Quinetic switches. The toilet light and fan are a combined unit but
have the usual live/switched live/neutral connections which specifies
that it should be run from a 3A FCU.

So, how do I fulfil the isolation requirement for the fan (among other
things)? The Quinetic receiver has just live, neutral and two
switched live connections.

Opinion genrally seems to be that the 3A protection is rather
pointless when a toilet light/fan is run from a 6A MCB protected
circuit. So, should I just put a 3-pole fan isolator to isolate the
toilet fan/light and leave it at that? I don't really want to put a
3A FCU *before* the Quinetic receiver because it will then switch off
the main bedroom light as well as the toilet.

Where should the isolator be, putting it anywhere in/around the toilet
cubicle or bedroom gets us back into chasing hard walls. I guess a
lockable one in the eaves reachable by opening a small door would be
the 'right' way to do it.

Comments and ideas very welcome.

--
Chris Green
·

Most fan isolator switches for bathrooms and WC are positioned outside the room above the entrance doorway. As far as I can see you only need to provide isolation for the fan the rest I would suggest is wired directly into the lighting circuit you describe. I do not know how you intend to create the cubicle but presume it will be a studded structure with a wall and doorway at right angles to each other. If so you should be able to wire in the isolator switch during its construction.

Richard

Tricky Dicky wrote:
Most fan isolator switches for bathrooms and WC are positioned outside
the room above the entrance doorway. As far as I can see you only need
to provide isolation for the fan the rest I would suggest is wired directly
into the lighting circuit you describe. I do not know how you intend to
create the cubicle but presume it will be a studded structure with a wall
and doorway at right angles to each other. If so you should be able to
wire in the isolator switch during its construction.

That is a good point, the cubicle will be a standard dry-lined
construction so, as you say, I can put the isolator switch high up and
out of the way somewhere there. Is there any good reason for the
isolator switch being outside the cubicle?

The light is integrated into the fan, though in principle I can't see
any reason for not wiring it such that it can be turned on even when
the fan is isolated.

Another thought - would one 'service' the fan from the 'user' side or
would it be more reasonable to expect whoever services the fan to want
to access the back of it? That would affect where you'd want to put
the isolator switch. ... and anyway, who ever services a toilet
extract fan? :-)

--
Chris Green
·

On 06/05/2019 13:04, Tricky Dicky wrote:
Most fan isolator switches for bathrooms and WC are positioned outside the room above the entrance doorway. As far as I can see you only need to provide isolation for the fan the rest I would suggest is wired directly into the lighting circuit you describe. I do not know how you intend to create the cubicle but presume it will be a studded structure with a wall and doorway at right angles to each other. If so you should be able to wire in the isolator switch during its construction.

They were usually placed outside because of misread 16th edition regs.

The OP is probably going to need RCBOs to meet the 18th edition regs.



--
Adam

ARW wrote:
On 06/05/2019 13:04, Tricky Dicky wrote:
Most fan isolator switches for bathrooms and WC are positioned outside
the room above the entrance doorway. As far as I can see you only need
to provide isolation for the fan the rest I would suggest is wired directly
into the lighting circuit you describe. I do not know how you intend to
create the cubicle but presume it will be a studded structure with a wall
and doorway at right angles to each other. If so you should be able to
wire in the isolator switch during its construction.

They were usually placed outside because of misread 16th edition regs.

The OP is probably going to need RCBOs to meet the 18th edition regs.

Ah, a good point, this is I guess an addition rather than a
replacement so I need to conform to 18th edition. I should be able to
replace the existing 6A MCB with an RCBO I think, just need to check
the space in the CU.

--
Chris Green
·

Chris Green wrote:

Tricky Dicky wrote:
Most fan isolator switches for bathrooms and WC are positioned outside
the room above the entrance doorway. As far as I can see you only need
to provide isolation for the fan the rest I would suggest is wired directly
into the lighting circuit you describe. I do not know how you intend to
create the cubicle but presume it will be a studded structure with a wall
and doorway at right angles to each other. If so you should be able to
wire in the isolator switch during its construction.

That is a good point, the cubicle will be a standard dry-lined
construction so, as you say, I can put the isolator switch high up and
out of the way somewhere there. Is there any good reason for the
isolator switch being outside the cubicle?

Not unless you have a bath or shower in your cubicle, which sounds
unlikely. But I would put it where no-one is likely to touch it with
wet hands. High up should do.



The light is integrated into the fan, though in principle I can't see
any reason for not wiring it such that it can be turned on even when
the fan is isolated.

I have a similar appliance. That is I suppose ok if the fan *can*
actually be serviced without risk of shock from the light circuit. Mine
couldn't be, as the light needs dismantling to get at the fan.



Another thought - would one 'service' the fan from the 'user' side or
would it be more reasonable to expect whoever services the fan to want
to access the back of it? That would affect where you'd want to put
the isolator switch. ... and anyway, who ever services a toilet
extract fan? :-)


--

Roger Hayter

Roger Hayter wrote:
Chris Green wrote:

Tricky Dicky wrote:
Most fan isolator switches for bathrooms and WC are positioned outside
the room above the entrance doorway. As far as I can see you only need
to provide isolation for the fan the rest I would suggest is wired directly
into the lighting circuit you describe. I do not know how you intend to
create the cubicle but presume it will be a studded structure with a wall
and doorway at right angles to each other. If so you should be able to
wire in the isolator switch during its construction.

That is a good point, the cubicle will be a standard dry-lined
construction so, as you say, I can put the isolator switch high up and
out of the way somewhere there. Is there any good reason for the
isolator switch being outside the cubicle?

Not unless you have a bath or shower in your cubicle, which sounds
unlikely. But I would put it where no-one is likely to touch it with
wet hands. High up should do.

No, no bath or shower, high up makes sense. I just thought it would
be more out of sight inside rather than outside.


The light is integrated into the fan, though in principle I can't
see any reason for not wiring it such that it can be turned on
even when the fan is isolated.

I have a similar appliance. That is I suppose ok if the fan *can*
actually be serviced without risk of shock from the light circuit.
Mine couldn't be, as the light needs dismantling to get at the fan.

It's a 12v lamp with a transformer, I guess as long as the mains side
of the transformer is inaccessible when servicing the fan then it
would be OK. However I can't see how the lamp being on would help
much so I think I'll drop the idea and isolate the whole thing! :-)

--
Chris Green
·

On Mon, 6 May 2019 15:43:49 +0100, Chris Green wrote:

ARW wrote:
On 06/05/2019 13:04, Tricky Dicky wrote:
Most fan isolator switches for bathrooms and WC are positioned outside
the room above the entrance doorway. As far as I can see you only need
to provide isolation for the fan the rest I would suggest is wired directly
into the lighting circuit you describe. I do not know how you intend to
create the cubicle but presume it will be a studded structure with a wall
and doorway at right angles to each other. If so you should be able to
wire in the isolator switch during its construction.

They were usually placed outside because of misread 16th edition regs.

The OP is probably going to need RCBOs to meet the 18th edition regs.

Ah, a good point, this is I guess an addition rather than a
replacement so I need to conform to 18th edition. I should be able to
replace the existing 6A MCB with an RCBO I think, just need to check
the space in the CU.

From not-very-accurate measuring, it looks as if a miniature RCBO will
replace an MCB. My board is a Wylex from about 1990 and a Wylex mini-RCBO
seems to be OK.
--
Peter.
The gods will stay away
whilst religions hold sway

On Monday, 6 May 2019 14:51:25 UTC+1, ARW wrote:
The OP is probably going to need RCBOs to meet the 18th edition regs.

Or, if the CU can't take an RCBO, an RCD FCU fixed somewhere convenient.

Owain

On Monday, 6 May 2019 11:48:05 UTC+1, Chris Green wrote:
I don't really want to put a 3A FCU *before* the Quinetic
receiver because it will then switch off the main bedroom
light as well as the toilet.

Especially if the toilet doesn't have a window, a £15 LED emergency light may be useful, both for fan maintenance and for emergency use.

Owain

On 06/05/2019 22:19, wrote:
On Monday, 6 May 2019 14:51:25 UTC+1, ARW wrote:
The OP is probably going to need RCBOs to meet the 18th edition regs.

Or, if the CU can't take an RCBO, an RCD FCU fixed somewhere convenient.


Yes.


--
Adam