Getting differing messages on what to protect (RCD) and what not...

What's the general view ?

Lighting ... NO
Ring Mains... YES
Install a (unprotected) separate socket for Fridge Freezer Yes or No ?
Cooker Outlet ..Yes or No ?
Gas Boiler ... Yes or No ?
Outside supply (unprotected) use individual plug-in RCD's for portable
tools. Yes or No

One guy I spoke to said: Install a CU with a 100mA main RCD and then
use 30mA RCBO's but all the CU's I've seen have 30mA main RCD's ... Is
this a real option ?

and finally: If you were doing a re-wire now would you connect the
bathroom lighting cct seperatly via a RCBO or is there danger that
this requirement in the 17th edition will not be ratified.

In article m,
ac1951 writes:
Getting differing messages on what to protect (RCD) and what not...

What's the general view ?

Lighting ... NO
Ring Mains... YES
Install a (unprotected) separate socket for Fridge Freezer Yes or No ?

Unprotected. Can also feed boiler, alarm, any life support systems (e.g.
tropical fish tank with a dedicated plug-in RCD).

Cooker Outlet ..Yes or No ?

Unprotected.

Gas Boiler ... Yes or No ?

Unprotected.

Outside supply (unprotected) use individual plug-in RCD's for portable
tools. Yes or No

Use an RCBO or separate hard-wired RCD from the unprotected side.
(Individual plug-in RCD's wouldn't conform to regs.)
I would also recommend an isolating switch for the outdoor circuit
inside the house (which could be part of the RCD protection).

One guy I spoke to said: Install a CU with a 100mA main RCD and then
use 30mA RCBO's but all the CU's I've seen have 30mA main RCD's ... Is
this a real option ?

That option is only required if your earthing is via your own
earth rod (TT system), rather than by an earthing terminal
provided by the supply company (TN system).

and finally: If you were doing a re-wire now would you connect the
bathroom lighting cct seperatly via a RCBO or is there danger that
this requirement in the 17th edition will not be ratified.

There's no chance that what you describe will become the norm; RCBO's
are too expensive and not available for many of the budget CU's often
used in initial installs. I suspect it's most likely to be done with
an FCU taking power from an RCD-protected ring circuit, which in
effect replaces the fan isolator which becomes no longer necessary,
so there's no cost increase.

Personally, I would not RCD protect the bathroom light at this time,
but I do fit them out of reach. I might consider RCD protection if
the lighting was in reach, such as makeup lights around a mirror.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

In article ,
(Andrew Gabriel) writes:
Cooker Outlet ..Yes or No ?

Unprotected.

Just to add -- don't use a cooker switch with integral socket.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Andrew Gabriel wrote:
In article m,
ac1951 writes:
Getting differing messages on what to protect (RCD) and what not...

What's the general view ?

Lighting ... NO
Ring Mains... YES
Install a (unprotected) separate socket for Fridge Freezer Yes or No ?

Unprotected. Can also feed boiler, alarm, any life support systems (e.g.
tropical fish tank with a dedicated plug-in RCD).

Cooker Outlet ..Yes or No ?

Unprotected.

Gas Boiler ... Yes or No ?

Unprotected.

I did a rewire recently, following the above scheme, and it was all
checked over and approved by a sparks... however he mentioned that
although he considered it barmy, he couldn't have approved it once the
forthcoming 17th edn came in to force - I think the issue would have
been over provision of the dedicated unprotected fridge/freezer socket?

Is that so? - presumably would be resolvable by hardwiring the freezer
with an FCU?

David

There's no chance that what you describe will become the norm; RCBO's
are too expensive and not available for many of the budget CU's often
used in initial installs.

I'm not so sure. Part of the reason for RCBO's expense will be the
level of use. Once demand increases, price will drop.

I suspect it's most likely to be done with
an FCU taking power from an RCD-protected ring circuit, which in
effect replaces the fan isolator which becomes no longer necessary,
so there's no cost increase.

Yup, agreed. Certainly to start with.

I suspect it's most likely to be done with an FCU taking power from an
RCD-protected ring circuit, which ineffect replaces the fan isolator
which becomes no longer necessary, so there's no cost increase.

Yup, agreed. Certainly to start with.

Would you install the FCU inside or outside the Bathroom ?

In article . com,
ac1951 writes:
I suspect it's most likely to be done with an FCU taking power from an
RCD-protected ring circuit, which ineffect replaces the fan isolator
which becomes no longer necessary, so there's no cost increase.

Yup, agreed. Certainly to start with.

Would you install the FCU inside or outside the Bathroom ?

Inside, in Zone 3 or further (and out of reach for normal use).
If it's not inside the bathroom, it would need to be able to
be locked in the off position, which not all FCU's are (check
for a padlock hole in the opened fuse carrier).

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

"Andrew Gabriel" wrote in message
...
In article m,
ac1951 writes:
Getting differing messages on what to protect (RCD) and what not...



and finally: If you were doing a re-wire now would you connect the
bathroom lighting cct seperatly via a RCBO or is there danger that
this requirement in the 17th edition will not be ratified.

There's no chance that what you describe will become the norm; RCBO's
are too expensive and not available for many of the budget CU's often
used in initial installs. I suspect it's most likely to be done with
an FCU taking power from an RCD-protected ring circuit, which in
effect replaces the fan isolator which becomes no longer necessary,
so there's no cost increase.

Personally, I would not RCD protect the bathroom light at this time,
but I do fit them out of reach. I might consider RCD protection if
the lighting was in reach, such as makeup lights around a mirror.


It is my intention when the new rules come in to use an RCD fused spur off
the lighting ciruit for the bathroom lights. This is for a cost reasons.
Most houses do not have the CU near the bathroom and the labour for
installing one radial off an RCBO for one room would have to be passed on to
the customer.

Adam

ac1951 wrote:

and finally: If you were doing a re-wire now would you connect the
bathroom lighting cct seperatly via a RCBO or is there danger that
this requirement in the 17th edition will not be ratified.

I'd say there is no doubt at all that the 17th ed. will require 30 mA
RCD protection for all bath/shower room circuits.

Apparently the published 17th ed. (BS 7671:2008, due in January,
effective from 1st July) will contain many changes from this year's
draft edition, and these point in the direction of increased RCD
protection (some may choose to call it paranoia).

The REALLY BIG potential change (final decision said to be mid-November)
concerns cables buried in walls at less than 50 mm depth. Here the
requirement of the draft edition [522.6.6] is very similar to the 16th
ed. in that such cables must comply with one of three options - i.e.:

- use of a cable type with an earthed metal covering (SWA, FP200,
Earthshield (BS 8436), etc.) or;

- must be in earthed metal conduit or trunking (metal capping doesn't
count), or;

- must be in the "safe zones".

For ordinary house wiring in T&E the safe zones option is of course the
one used.

Now the draft 17th added proposed reg. 522.6.7 which allowed a get-out,
i.e. if none of the three above options could be applied then 30 mA RCD
protection could be used instead, which seemed quite sensible.

It now appears that all this will change, such that all power cables
buried at less than 50 mm depth will require 30 mA RCD protection,
_even_if_in_the_safe_zones_ unless one of the above special cable types,
or metal conduit/trunking is used.

Should this turn out to be true then _all_circuits_ wired in T&E will
need to be 30 mA RCD'd, unless buried to what is normally an
impracticable depth. Non-RCD protected circuits will need special cable
types. Perhaps individual circuit RCBOs will become the norm...

--
Andy

Andrew Gabriel wrote:

Just to add -- don't use a cooker switch with integral socket.

Why not?

Ta
Andy

In article ,
Andy Champ writes:
Andrew Gabriel wrote:

Just to add -- don't use a cooker switch with integral socket.

Why not?

Don't really want the cooker RCD protected, but you do want
all worktop sockets RCD protected, where things like kettles
are plugged in.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

In article ,
Andy Wade writes:

It now appears that all this will change, such that all power cables
buried at less than 50 mm depth will require 30 mA RCD protection,
_even_if_in_the_safe_zones_ unless one of the above special cable types,
or metal conduit/trunking is used.

What's the justification for this?
Or is it just knee jerk without any risk analysis to back it up?

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Andrew Gabriel wrote:

What's the justification for this?

I guess it's that it will give supplementary direct contact protection
for people, ignorant of the safe zones concept, drilling, nailing or
screwing through live cables.

Or is it just knee jerk without any risk analysis to back it up?

No idea. The makers of RCDs and the more expensive cable types will
doubtless be pleased though...

--
Andy

ac1951 wrote:
Getting differing messages on what to protect (RCD) and what not...

What's the general view ?

Assuming you don't have a TT supply:

Lighting ... NO

No RCD

Ring Mains... YES

RCD

Install a (unprotected) separate socket for Fridge Freezer Yes or No ?

No RCD

Cooker Outlet ..Yes or No ?

No RCD

Gas Boiler ... Yes or No ?

No RCD

Outside supply (unprotected) use individual plug-in RCD's for portable
tools. Yes or No

If you are just talking about sockets for feeding appliances outside
then RCD. If you are talking abut submain feeds to outbuildiongs then see:

http://wiki.diyfaq.org.uk/index.php?...ricity_outside

One guy I spoke to said: Install a CU with a 100mA main RCD and then
use 30mA RCBO's but all the CU's I've seen have 30mA main RCD's ... Is
this a real option ?

Hmm, I suspect he did not quite know what he was on about. This sort of
setup is only really required on TT systems, and then the main RCD would
need to be a time delayed type so as to discriminate with the downstream
RCBOs on current imbalance faults.

You can change the RCD in a CU if required for a different trip
threshold one.

and finally: If you were doing a re-wire now would you connect the
bathroom lighting cct seperatly via a RCBO or is there danger that
this requirement in the 17th edition will not be ratified.

Can't see it changing in a big way now since the time for comments have
passed and it will be issued soon.



--
Cheers,

John.

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

Lobster wrote:

I did a rewire recently, following the above scheme, and it was all
checked over and approved by a sparks... however he mentioned that
although he considered it barmy, he couldn't have approved it once the
forthcoming 17th edn came in to force - I think the issue would have
been over provision of the dedicated unprotected fridge/freezer socket?

Is that so? - presumably would be resolvable by hardwiring the freezer
with an FCU?

As long as it was clearly labelled that the socket was for Freezer use
only then IIUC it ought to be fine.

--
Cheers,

John.

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

Andrew Gabriel wrote:

Would you install the FCU inside or outside the Bathroom ?

Inside, in Zone 3 or further (and out of reach for normal use).
If it's not inside the bathroom, it would need to be able to
be locked in the off position, which not all FCU's are (check
for a padlock hole in the opened fuse carrier).

pedant_mode
What used to be Zone 3, but is now outside the zones ;-)
/pedant_mode

--
Cheers,

John.

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

ARWadsworth wrote:

It is my intention when the new rules come in to use an RCD fused spur
off the lighting ciruit for the bathroom lights. This is for a cost
reasons. Most houses do not have the CU near the bathroom and the labour
for installing one radial off an RCBO for one room would have to be
passed on to the customer.

There is also a certain logical elegance there in that turning off the
lighting circuit for that floor will also turn off the bathroom lights.

--
Cheers,

John.

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

Andy Wade wrote:

Should this turn out to be true then _all_circuits_ wired in T&E will
need to be 30 mA RCD'd, unless buried to what is normally an
impracticable depth. Non-RCD protected circuits will need special cable
types. Perhaps individual circuit RCBOs will become the norm...

Which by virtue of the switch drops would include lighting circuits as
well. This would seem to have the same negative safety implications of
the 15th edition "whole house RCD" all over again.

--
Cheers,

John.

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

"Andrew Gabriel" wrote in message
...
What's the justification for this?
Or is it just knee jerk without any risk analysis to back it up?

RCBO Lobbyists, er oops, Manufacturers :-)
Quite seriously, the major manufacturers do directly drive
IEE BS EU committee standards. They target the committee
members quite relentlessly with a very blatant sales agenda.
Challenge and you get a new corner office: window seat.
It is endemic within the EU "health & safety" crowd.

I am not surprised. I had expected "RCBO for every single
final circuit" re IEE & Part P wording H&S-extremous. IEE
will cite a) drilling-in-bathroom fatality re cable angle, or b)
electrified spice rack, or c) other trades ignorant of zones.


Q - Does FP200 qualify as concentric, earthed metal covering?

I ask because whilst FP200 has a bare CPC in direct contact
with a metal shield, the shield is merely electromagnetic shielding
foil. Foil has substantially less fault current capability vs MICCs.

I am thinking of cable penetration by ubiquitous picture nail,
small dia, contacting only an small area of foil & phase. A small
partial circumference of wafer thin foil carries fault current. For
RCD protection that is 30ma, for 30A Type-C MCB it is 300A.
Adiabatic calculation for that bit of foil would be interesting.
MICCS, SWA & FP400 are all be ok, but is FP200??

FP200 has a 6r bend radius, 57mm for 2.5mm 2-core-&-earth.
Keeping within 6r bend radius is not easy re plaster depth or
conduit box rear exit (I suspect most strip the sheath off).
--
DB.

The makers of RCDs and the more expensive
cable types will doubtless be pleased though...

Is it Belgium or Portugal that requires basically a
semi-armoured domestic cable? There are no zones,
either cables are at some silly-depth or are armoured.

France insulates the CPC, altho I wonder if in doing
so they reduce the insulation thickness on Phase/N.


Each country seems to use historic "freak case" to drive
standards, the IEE/UK/Part-P picking every worst case
to drive each one of its standards in the end. Plus they
can not even quote the facts correctly in doing so. A
brilliant way of creating committee employment. The result
is a camel - and people use cowboys vs electricians, even
more so when electricians/corgi milk people by fake regs.

An important step in a formal risk management process is
a cost benefit analysis. Now considering Part P, Brown,
Govt in general, I suspect we should not expect any better.
--
DB.

Dorothy Bradbury wrote:

IEE will cite a) drilling-in-bathroom fatality re cable angle, or b)
electrified spice rack, or c) other trades ignorant of zones.

And IEC, CENELEC and the H-word...

Q - Does FP200 qualify as concentric, earthed metal covering?

FP200 Gold, as it's now called, is to BS 7629-1, which is not one of the
standards listed in 522-06-06 (522.6.6 in draft 17th ed.) - so no.
Apologies for misleading you in an earlier post.

I ask because whilst FP200 has a bare CPC in direct contact
with a metal shield, the shield is merely electromagnetic shielding
foil. Foil has substantially less fault current capability vs MICCs.

I am thinking of cable penetration by ubiquitous picture nail,
small dia, contacting only an small area of foil & phase. A small
partial circumference of wafer thin foil carries fault current. For
RCD protection that is 30ma, for 30A Type-C MCB it is 300A.
Adiabatic calculation for that bit of foil would be interesting.
MICCS, SWA & FP400 are all be ok, but is FP200??

The same issue arises with the BS 8436 cables: you're confined to Type B
MCBs or RCBOs of energy limiting class 3. This MS Word document from
the ECA has chapter and verse:
http://www.voltimum.co.uk//popup.php...rd,%252029.5kB

--
Andy

The same issue arises with the BS 8436 cables: you're confined
to Type B MCBs or RCBOs of energy limiting class 3. This MS
Word document from the ECA has chapter and verse:
http://www.voltimum.co.uk//popup.php...rd,%252029.5kB

Great - thanks for the clarification.

Had no plans to knock nails into cables :-)))
--
DB.

On Sat, 10 Nov 2007 14:44:31 GMT someone who may be "ARWadsworth"
wrote this:-

It is my intention when the new rules come in to use an RCD fused spur off
the lighting ciruit for the bathroom lights. This is for a cost reasons.
Most houses do not have the CU near the bathroom and the labour for
installing one radial off an RCBO for one room would have to be passed on to
the customer.

Also in a "typical" two floor house with the bathroom upstairs the
upstairs lighting circuit is likely to be easily accessible, unlike
the upstairs power circuits which are likely to be under the
upstairs floor.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

"David Hansen" wrote in message
...
On Sat, 10 Nov 2007 14:44:31 GMT someone who may be "ARWadsworth"
wrote this:-

It is my intention when the new rules come in to use an RCD fused spur off
the lighting ciruit for the bathroom lights. This is for a cost reasons.
Most houses do not have the CU near the bathroom and the labour for
installing one radial off an RCBO for one room would have to be passed on
to
the customer.

Also in a "typical" two floor house with the bathroom upstairs the
upstairs lighting circuit is likely to be easily accessible, unlike
the upstairs power circuits which are likely to be under the
upstairs floor.

I suspect the cost of the RCD fused spur will be offset by not having to
supply earth clamps and the time saved laying the 4mm earth cable for the
supplemetary bonding.

The other reason is that if the RCD fused spur trips due to moisure ingress
any call outs are not urgent as the customers TV is still working.

Adam

It is my intention when the new rules come in to use an RCD fused spur off
the lighting ciruit for the bathroom lights. This is for a cost reasons.
Most houses do not have the CU near the bathroom and the labour for
installing one radial off an RCBO for one room would have to be passed on
to the customer.

In my case the CH combi boiler is in a cupboard (old airing cupboard)
in the bathroom.
Does that mean the supply to this would need to be RCD protected.

Andrew Gabriel wrote:
In article ,
Andy Wade writes:

It now appears that all this will change, such that all power cables
buried at less than 50 mm depth will require 30 mA RCD protection,
_even_if_in_the_safe_zones_ unless one of the above special cable types,
or metal conduit/trunking is used.

What's the justification for this?
Or is it just knee jerk without any risk analysis to back it up?

What will it cost over the next 20 years? With a 40 year mean
installation life, 30 million houses and 1 extra rcbo (dropped to a
mean £15 price) thats
0.5x 30 mill x £15 = £225 million.

And how many lives will it save: judging by the last 20 years about
2. £112 milion per life saved.

Compare this to the numerous other ways to save lives in quantity
at a fraction of the cost... hard to see how it can be a sensibly
analysed policy, though I'm open to education.


NT

In article . com,
writes:
Andrew Gabriel wrote:
In article ,
Andy Wade writes:

It now appears that all this will change, such that all power cables
buried at less than 50 mm depth will require 30 mA RCD protection,
_even_if_in_the_safe_zones_ unless one of the above special cable types,
or metal conduit/trunking is used.

What's the justification for this?
Or is it just knee jerk without any risk analysis to back it up?

What will it cost over the next 20 years? With a 40 year mean
installation life, 30 million houses and 1 extra rcbo (dropped to a
mean £5 price) thats
0.5x 30 mill x £5 = £225 million.

And how many lives will it save: judging by the last 20 years about
2. £12 milion per life saved.

Compare this to the numerous other ways to save lives in quantity
at a fraction of the cost... hard to see how it can be a sensibly
analysed policy, though I'm open to education.

I was doing that mental calculation yesterday.

It's sad that something that has been very well respected worldwide
(as in the UK Wiring Regs) looks like it's selling out to commercial
interests rather than remaining objective based on risk analysis.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

"ARWadsworth" wrote in message
.uk...

"Andrew Gabriel" wrote in message
...
In article m,
ac1951 writes:
Getting differing messages on what to protect (RCD) and what not...



and finally: If you were doing a re-wire now would you connect the
bathroom lighting cct seperatly via a RCBO or is there danger that
this requirement in the 17th edition will not be ratified.

There's no chance that what you describe will become the norm; RCBO's
are too expensive and not available for many of the budget CU's often
used in initial installs. I suspect it's most likely to be done with
an FCU taking power from an RCD-protected ring circuit, which in
effect replaces the fan isolator which becomes no longer necessary,
so there's no cost increase.

Personally, I would not RCD protect the bathroom light at this time,
but I do fit them out of reach. I might consider RCD protection if
the lighting was in reach, such as makeup lights around a mirror.


It is my intention when the new rules come in to use an RCD fused spur off
the lighting ciruit for the bathroom lights. This is for a cost reasons.
Most houses do not have the CU near the bathroom and the labour for
installing one radial off an RCBO for one room would have to be passed on
to the customer.

Fitting an RCD fused spur off the lighting circuit and supplying the b/room
lights and fans, etc, would this preclude equipotential bonding in a
bathroom?

"John Rumm" wrote in message
...
ARWadsworth wrote:

It is my intention when the new rules come in to use an RCD fused spur
off the lighting ciruit for the bathroom lights. This is for a cost
reasons. Most houses do not have the CU near the bathroom and the labour
for installing one radial off an RCBO for one room would have to be
passed on to the customer.

There is also a certain logical elegance there in that turning off the
lighting circuit for that floor will also turn off the bathroom lights.

It would if there was an RCD or not.

"ac1951" wrote in message
oups.com...

It is my intention when the new rules come in to use an RCD fused spur
off
the lighting ciruit for the bathroom lights. This is for a cost
reasons.
Most houses do not have the CU near the bathroom and the labour for
installing one radial off an RCBO for one room would have to be passed
on
to the customer.

In my case the CH combi boiler is in a cupboard (old airing cupboard)
in the bathroom.
Does that mean the supply to this would need to be RCD protected.

If it is in a cupboard, no, as far as I believe.

"Doctor Drivel" wrote in message
reenews.net...

"ARWadsworth" wrote in message
.uk...

"Andrew Gabriel" wrote in message
...
In article m,
ac1951 writes:
Getting differing messages on what to protect (RCD) and what not...



and finally: If you were doing a re-wire now would you connect the
bathroom lighting cct seperatly via a RCBO or is there danger that
this requirement in the 17th edition will not be ratified.

There's no chance that what you describe will become the norm; RCBO's
are too expensive and not available for many of the budget CU's often
used in initial installs. I suspect it's most likely to be done with
an FCU taking power from an RCD-protected ring circuit, which in
effect replaces the fan isolator which becomes no longer necessary,
so there's no cost increase.

Personally, I would not RCD protect the bathroom light at this time,
but I do fit them out of reach. I might consider RCD protection if
the lighting was in reach, such as makeup lights around a mirror.


It is my intention when the new rules come in to use an RCD fused spur
off the lighting ciruit for the bathroom lights. This is for a cost
reasons. Most houses do not have the CU near the bathroom and the labour
for installing one radial off an RCBO for one room would have to be
passed on to the customer.

Fitting an RCD fused spur off the lighting circuit and supplying the
b/room lights and fans, etc, would this preclude equipotential bonding in
a bathroom?


AFAIK the 17th edition not require supplemetary bonding in bathrooms but all
electrical circuits in the bathroom will need to be 30mA RCD protected.

Adam

"ARWadsworth" wrote in message
.uk...

"Doctor Drivel" wrote in message
reenews.net...

"ARWadsworth" wrote in message
.uk...

"Andrew Gabriel" wrote in message
...
In article m,
ac1951 writes:
Getting differing messages on what to protect (RCD) and what not...



and finally: If you were doing a re-wire now would you connect the
bathroom lighting cct seperatly via a RCBO or is there danger that
this requirement in the 17th edition will not be ratified.

There's no chance that what you describe will become the norm; RCBO's
are too expensive and not available for many of the budget CU's often
used in initial installs. I suspect it's most likely to be done with
an FCU taking power from an RCD-protected ring circuit, which in
effect replaces the fan isolator which becomes no longer necessary,
so there's no cost increase.

Personally, I would not RCD protect the bathroom light at this time,
but I do fit them out of reach. I might consider RCD protection if
the lighting was in reach, such as makeup lights around a mirror.


It is my intention when the new rules come in to use an RCD fused spur
off the lighting ciruit for the bathroom lights. This is for a cost
reasons. Most houses do not have the CU near the bathroom and the labour
for installing one radial off an RCBO for one room would have to be
passed on to the customer.

Fitting an RCD fused spur off the lighting circuit and supplying the
b/room lights and fans, etc, would this preclude equipotential bonding in
a bathroom?


AFAIK the 17th edition not require supplemetary bonding in bathrooms but
all electrical circuits in the bathroom will need to be 30mA RCD
protected.

...and the 17th has not been ratified yet!!!

wrote in message
s.com...
There's no chance that what you describe will become the norm; RCBO's
are too expensive and not available for many of the budget CU's often
used in initial installs.

I'm not so sure. Part of the reason for RCBO's expense will be the
level of use. Once demand increases, price will drop.

I have the impression they want RCBOs to be the norm as they are Germany in
new builds or re-wires.

Doctor Drivel wrote:

It is my intention when the new rules come in to use an RCD fused
spur off the lighting ciruit for the bathroom lights. This is for a
cost reasons. Most houses do not have the CU near the bathroom and
the labour for installing one radial off an RCBO for one room would
have to be passed on to the customer.

There is also a certain logical elegance there in that turning off the
lighting circuit for that floor will also turn off the bathroom lights.

It would if there was an RCD or not.

Not if the bathroom lighting is wired from a FCU fed by a socket
circuit, which would be the cheapest way of meeting the requirement
since the socket circuit will already have the pre-requisite RCD
protection.

--
Cheers,

John.

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

"John Rumm" wrote in message
...
Doctor Drivel wrote:

It is my intention when the new rules come in to use an RCD fused
spur off the lighting ciruit for the bathroom lights. This is for a
cost reasons. Most houses do not have the CU near the bathroom and the
labour for installing one radial off an RCBO for one room would have to
be passed on to the customer.

There is also a certain logical elegance there in that turning off the
lighting circuit for that floor will also turn off the bathroom lights.

It would if there was an RCD or not.

Not if the bathroom lighting is
wired from a FCU fed by a socket circuit,

He didn't say that. He mentioned the lighting circuit. Having an FCU/RCD off
the lighting circuit to supply all of the power in bathroom (light and fan),
which is normal, will only need one RCD off the lighting circuit.

which would be the cheapest way of meeting the requirement since the
socket circuit will already have the pre-requisite RCD protection.

What you are proposing is have all the bathroom power off an RCD socket
circuit via a fused spur to conform to the 17th and do away with
equipotential bonding. It will work, but you have a lighting circuit not on
the lighting circuit, which confuses.

"ARWadsworth" wrote in message
.uk...

"Doctor Drivel" wrote in message
reenews.net...

"ARWadsworth" wrote in message
.uk...

"Andrew Gabriel" wrote in message
...
In article m,
ac1951 writes:
Getting differing messages on what to protect (RCD) and what not...



and finally: If you were doing a re-wire now would you connect the
bathroom lighting cct seperatly via a RCBO or is there danger that
this requirement in the 17th edition will not be ratified.

There's no chance that what you describe will become the norm; RCBO's
are too expensive and not available for many of the budget CU's often
used in initial installs. I suspect it's most likely to be done with
an FCU taking power from an RCD-protected ring circuit, which in
effect replaces the fan isolator which becomes no longer necessary,
so there's no cost increase.

Personally, I would not RCD protect the bathroom light at this time,
but I do fit them out of reach. I might consider RCD protection if
the lighting was in reach, such as makeup lights around a mirror.


It is my intention when the new rules come in to use an RCD fused spur
off the lighting ciruit for the bathroom lights. This is for a cost
reasons. Most houses do not have the CU near the bathroom and the labour
for installing one radial off an RCBO for one room would have to be
passed on to the customer.

Fitting an RCD fused spur off the lighting circuit and supplying the
b/room lights and fans, etc, would this preclude equipotential bonding in
a bathroom?


AFAIK the 17th edition not require supplemetary bonding in bathrooms but
all electrical circuits in the bathroom will need to be 30mA RCD
protected.

When is the 17th coming in?

"ARWadsworth" wrote in message
.uk...

"Doctor Drivel" wrote in message
reenews.net...

"ARWadsworth" wrote in message
.uk...

"Andrew Gabriel" wrote in message
...
In article m,
ac1951 writes:
Getting differing messages on what to protect (RCD) and what not...



and finally: If you were doing a re-wire now would you connect the
bathroom lighting cct seperatly via a RCBO or is there danger that
this requirement in the 17th edition will not be ratified.

There's no chance that what you describe will become the norm; RCBO's
are too expensive and not available for many of the budget CU's often
used in initial installs. I suspect it's most likely to be done with
an FCU taking power from an RCD-protected ring circuit, which in
effect replaces the fan isolator which becomes no longer necessary,
so there's no cost increase.

Personally, I would not RCD protect the bathroom light at this time,
but I do fit them out of reach. I might consider RCD protection if
the lighting was in reach, such as makeup lights around a mirror.


It is my intention when the new rules come in to use an RCD fused spur
off the lighting ciruit for the bathroom lights. This is for a cost
reasons. Most houses do not have the CU near the bathroom and the labour
for installing one radial off an RCBO for one room would have to be
passed on to the customer.

Fitting an RCD fused spur off the lighting circuit and supplying the
b/room lights and fans, etc, would this preclude equipotential bonding in
a bathroom?

AFAIK the 17th edition not require supplemetary bonding in bathrooms but
all electrical circuits in the bathroom will need to be 30mA RCD
protected.

If the lighting in a bathroom is all 12v, do you need equipotential bonding
in the 16th?
In the 17th having 12v lighting, does it need to be RCD protected?

Doctor Drivel wrote:

It would if there was an RCD or not.

Not if the bathroom lighting is
wired from a FCU fed by a socket circuit,

He didn't say that. He mentioned the lighting circuit. Having an FCU/RCD

Indeed, and I agreed that it was an elegant solution.

which would be the cheapest way of meeting the requirement since the
socket circuit will already have the pre-requisite RCD protection.

What you are proposing is have all the bathroom power off an RCD socket
circuit via a fused spur to conform to the 17th and do away with
equipotential bonding. It will work, but you have a lighting circuit
not on the lighting circuit, which confuses.

see above... do try and keep up.

--
Cheers,

John.

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

"ARWadsworth" wrote in message
.uk...

"Doctor Drivel" wrote in message
reenews.net...

"ARWadsworth" wrote in message
.uk...

"Andrew Gabriel" wrote in message
...
In article m,
ac1951 writes:
Getting differing messages on what to protect (RCD) and what not...



and finally: If you were doing a re-wire now would you connect the
bathroom lighting cct seperatly via a RCBO or is there danger that
this requirement in the 17th edition will not be ratified.

There's no chance that what you describe will become the norm; RCBO's
are too expensive and not available for many of the budget CU's often
used in initial installs. I suspect it's most likely to be done with
an FCU taking power from an RCD-protected ring circuit, which in
effect replaces the fan isolator which becomes no longer necessary,
so there's no cost increase.

Personally, I would not RCD protect the bathroom light at this time,
but I do fit them out of reach. I might consider RCD protection if
the lighting was in reach, such as makeup lights around a mirror.


It is my intention when the new rules come in to use an RCD fused spur
off the lighting ciruit for the bathroom lights. This is for a cost
reasons. Most houses do not have the CU near the bathroom and the labour
for installing one radial off an RCBO for one room would have to be
passed on to the customer.

Fitting an RCD fused spur off the lighting circuit and supplying the
b/room lights and fans, etc, would this preclude equipotential bonding in
a bathroom?

AFAIK the 17th edition not require supplemetary bonding in bathrooms but
all electrical circuits in the bathroom will need to be 30mA RCD
protected.

I have read that the 17th will allow 3-pin mains voltage sockets in
bathrooms, as long as it is RCD protected. Is that so? If so, then a
socket off the ring main can be just run in. Probably have to be away from
the sink with minimum distance, etc..

"John Rumm" wrote in message
...
Andy Wade wrote:

Should this turn out to be true then _all_circuits_ wired in T&E will
need to be 30 mA RCD'd, unless buried to what is normally an
impracticable depth. Non-RCD protected circuits will need special cable
types. Perhaps individual circuit RCBOs will become the norm...

Which by virtue of the switch drops would include lighting circuits as
well. This would seem to have the same negative safety implications of the
15th edition "whole house RCD" all over again.

It is pretty clear they are forcing everyone to use RCBOs. Rather than a
bank of circuits being switched out by an RCD, each individual circuit only
need switching out by its own RCBO.