I notice that the NICEIC have recently updated their note about the
major changes between the 16th and 17th editions:
http://www.niceic.org.uk/17thedition...orChanges2.pdf
(file created 1st November).

Rumours regarding changes to regulation 522.6.6 of the public draft
edition appear to be confirmed - to quote:

"The requirements relating to cables concealed in a wall or partition
have been altered so that protection by a 30mA RCD is an additional
requirement for €˜unprotected cables (e.g. twin and earth cables
installed in a chase less than 50mm deep); it must be emphasised that
such cables must still be installed in €˜safe zones."

--
Andy

On 2007-12-02 10:27:24 +0000, Andy Wade said:

I notice that the NICEIC have recently updated their note about the
major changes between the 16th and 17th editions:
http://www.niceic.org.uk/17thedition...orChanges2.pdf
(file created 1st November).

Rumours regarding changes to regulation 522.6.6 of the public draft
edition appear to be confirmed - to quote:

"The requirements relating to cables concealed in a wall or partition
have been altered so that protection by a 30mA RCD is an additional
requirement for €˜unprotected cables (e.g. twin and earth cables
installed in a chase less than 50mm deep); it must be emphasised that
such cables must still be installed in €˜safe zones."



So do you read the implication of this as being 30mA RCD protection for
all circuits regardless of where the cables are run? i.e. even in
the 150mm safe zones? This implies whole house RCDs or RCBOs.

Andy Hall wrote:

So do you read the implication of this as being 30mA RCD protection for
all circuits regardless of where the cables are run? i.e. even in the
150mm safe zones?

In effect, yes. What it appears to mean is that if you want to run a
non-RCD-protected circuit then the cables must either

- be one of the prescribed types which incorporate an earthed armour,
screen or covering, or

- be run in earthed metal conduit, or

- be buried deeper than 50 mm in a wall, or

- be wholly surface-wired.

This implies whole house RCDs or RCBOs.

Or multiple RCDs, or some combination of RCDs and RCBOs.

--
Andy

On 2007-12-02 12:17:00 +0000, Andy Wade said:

Andy Hall wrote:

So do you read the implication of this as being 30mA RCD protection for
all circuits regardless of where the cables are run? i.e. even in
the 150mm safe zones?

In effect, yes. What it appears to mean is that if you want to run a
non-RCD-protected circuit then the cables must either

- be one of the prescribed types which incorporate an earthed armour,
screen or covering,

I haven't seen anything for interior use that fits this bill. Surely not SWA?




or

- be run in earthed metal conduit,

implies a lot of labour


or

- be buried deeper than 50 mm in a wall,


which can't be done in a modern domestic property.



or

- be wholly surface-wired.

which won't be aesthetically acceptable



This implies whole house RCDs or RCBOs.

Or multiple RCDs, or some combination of RCDs and RCBOs.

I think that I might go and buy some Honeywell shares (as in MK) .......

Or multiple RCDs, or some combination of RCDs and RCBOs.

I think that I might go and buy some Honeywell shares (as in MK) .......

I think we're about to see a big ramp-down in the price of RCBO's (as
there's nothing particularly expensive materials wise or rocket
science about the technology in them) and for the manufacturers to
launch CU's pre-populated with RCBO's at a much reduced bundle price.

On 2007-12-02 13:04:33 +0000, " said:


Or multiple RCDs, or some combination of RCDs and RCBOs.

I think that I might go and buy some Honeywell shares (as in MK) .......

I think we're about to see a big ramp-down in the price of RCBO's (as
there's nothing particularly expensive materials wise or rocket
science about the technology in them) and for the manufacturers to
launch CU's pre-populated with RCBO's at a much reduced bundle price.

Consumer units will need to be redesigned though - e,g, the busbar
arrangements, I would have thought ,because of the extra connections.

Andy Hall wrote:

I haven't seen anything for interior use that fits this bill. Surely
not SWA?

That's one option. The full list is:

- BS 5467 - SWA (XLPE/PVC)
- BS 6346 - SWA (PVC/PVC)
- BS 6724 - SWA (XLPE/LSF)
- BS 7846 - SWA (XLPE/OHLS)
- BS 8346 - e.g. 'Earthshield' [1]
- BS EN 60702-1 - MICC

[1] See
http://www.voltimum.co.uk/news/4178/...ng-cables.html

I think that I might go and buy some Honeywell shares (as in MK) .......

Might not be a bad idea...

--
Andy

On 2007-12-02 13:23:04 +0000, Andy Wade said:

Andy Hall wrote:

I haven't seen anything for interior use that fits this bill. Surely not SWA?

That's one option. The full list is:

- BS 5467 - SWA (XLPE/PVC)
- BS 6346 - SWA (PVC/PVC)
- BS 6724 - SWA (XLPE/LSF)
- BS 7846 - SWA (XLPE/OHLS)
- BS 8346 - e.g. 'Earthshield' [1]
- BS EN 60702-1 - MICC

[1] See
http://www.voltimum.co.uk/news/4178/...ng-cables.html

Ah, so add Pirelli to the portfolio. It seems that Earthshield is
not mechanical protection but rather that it is assumed that someone
driving in a nail will reach the CPC outer screen first and will then
hit a phase conductor, thus tripping the MCB?



I think that I might go and buy some Honeywell shares (as in MK) .......

Might not be a bad idea...

On Sun, 02 Dec 2007 12:17:00 +0000, Andy Wade
wrote:

Andy Hall wrote:

So do you read the implication of this as being 30mA RCD protection for
all circuits regardless of where the cables are run? i.e. even in the
150mm safe zones?

In effect, yes. What it appears to mean is that if you want to run a
non-RCD-protected circuit then the cables must either

- be one of the prescribed types which incorporate an earthed armour,
screen or covering, or

- be run in earthed metal conduit, or

- be buried deeper than 50 mm in a wall, or

- be wholly surface-wired.

This implies whole house RCDs or RCBOs.

Or multiple RCDs, or some combination of RCDs and RCBOs.

Sod that. Good job I used my old 4mm cooker radial circuit as a
non-RCD-protected circuit for the fridge-freezer. It shouldn't need
rewiring for a decade or two...

--
Frank Erskine

Andy Hall wrote:

Ah, so add Pirelli to the portfolio.

Or Prysmian, as the cable operation seems to itself these days.

It seems that Earthshield is not mechanical protection but rather
that it is assumed that someone driving in a nail will reach the CPC
outer screen first and will then hit a phase conductor, thus tripping
the MCB?

That principle in all cases, ultimately. The level of mechanical
protection obviously varies, steel conduit probably being the best.

Another point with BS 8436 cable is that the shield is very thin, so
there are constraints on what protective device can be used to keep
within the I^2*t capability of the cable. 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

Andy Wade wrote:
I notice that the NICEIC have recently updated their note about the
major changes between the 16th and 17th editions:
http://www.niceic.org.uk/17thedition...orChanges2.pdf
(file created 1st November).

Rumours regarding changes to regulation 522.6.6 of the public draft
edition appear to be confirmed - to quote:

"The requirements relating to cables concealed in a wall or partition
have been altered so that protection by a 30mA RCD is an additional
requirement for €˜unprotected cables (e.g. twin and earth cables
installed in a chase less than 50mm deep); it must be emphasised that
such cables must still be installed in €˜safe zones."

Once solution here would seem to be to treat all installs as we
currently would a TT one. That way one can still have "non protected"
(i.e. 100mA or higher trips thresholds and time delays) on circuits
where appropriate.


--
Cheers,

John.

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

John Rumm wrote:

Once solution here would seem to be to treat all installs as we
currently would a TT one. That way one can still have "non protected"
(i.e. 100mA or higher trips thresholds and time delays) on circuits
where appropriate.

How would that help? 100 mA and/or time-delayed RCDs will not meet the
30 mA / 40 ms requirement [in 415.1] for additional protection.

--
Andy

Andy Wade wrote:
I notice that the NICEIC have recently updated their note [...]

And here's the ECA's contribution:
http://www.eca.co.uk/17thEdition/17E...tation.pdf.pdf

--
Andy

Andy Wade wrote:
John Rumm wrote:

Once solution here would seem to be to treat all installs as we
currently would a TT one. That way one can still have "non protected"
(i.e. 100mA or higher trips thresholds and time delays) on circuits
where appropriate.

How would that help? 100 mA and/or time-delayed RCDs will not meet the
30 mA / 40 ms requirement [in 415.1] for additional protection.

Missed that bit... obviously it wouldn't

30mA trip seems excessive if the only intention is to protect the wiring
itself and against indirect contact risks (or whatever the new phrase
is) - especially on lighting circuits.

--
Cheers,

John.

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

And here's the ECA's contribution:
http://www.eca.co.uk/17thEdition/17E...tation.pdf.pdf

And the cost-benefit analysis and/or regulatory impact assessment is
where please?

--
Robin

In article 4752bc68@qaanaaq, Andy Hall writes
On 2007-12-02 13:23:04 +0000, Andy Wade
said:

Andy Hall wrote:

I haven't seen anything for interior use that fits this bill. Surely not SWA?

That's one option. The full list is:

- BS 5467 - SWA (XLPE/PVC)
- BS 6346 - SWA (PVC/PVC)
- BS 6724 - SWA (XLPE/LSF)
- BS 7846 - SWA (XLPE/OHLS)
- BS 8346 - e.g. 'Earthshield' [1]
- BS EN 60702-1 - MICC

[1] See
http://www.voltimum.co.uk/news/4178/...ng-cables.html

Ah, so add Pirelli to the portfolio. It seems that Earthshield is
not mechanical protection but rather that it is assumed that someone
driving in a nail will reach the CPC outer screen first and will then
hit a phase conductor, thus tripping the MCB?

I'm sure Pirelli has carried out tests but I wonder what the chances are
of the foil vaporising in an annulus around such a nail before a 32A
breaker trips?

When Mr W first raised this issue I assumed that everyone would just
move over to non-split CUs with everything on the trip or add an RCD to
the previously non-RCD side in retrofit, this would be far less than the
cost of specialist cabling and IMO it is cost that will drive this
market.
--
fred
Plusnet - I hope you like vanilla

On 02/12/2007 19:27, fred wrote:

I'm sure Pirelli has carried out tests but I wonder what the chances are
of the foil vaporising in an annulus around such a nail before a 32A
breaker trips?

Dunno, but surely the intention of the 17th Ed. is that there is no
worry about an MCB having to trip because an RCD (or RCBO) will do instead?

On 02/12/2007 18:42, Andy Wade wrote:

http://www.eca.co.uk/17thEdition/17E...tation.pdf.pdf

So rather than have no definition of a competent person it now has the
definition of ...

"A person who possesses sufficient technical knowledge and
experience for the nature of the electrical work undertaken
and is able at all times to prevent danger, and where
appropriate, injury to themselves and others."

At _ALL_ times?

In article , Andy Burns
writes
On 02/12/2007 19:27, fred wrote:

I'm sure Pirelli has carried out tests but I wonder what the chances are
of the foil vaporising in an annulus around such a nail before a 32A
breaker trips?

Dunno, but surely the intention of the 17th Ed. is that there is no
worry about an MCB having to trip because an RCD (or RCBO) will do instead?

IIUC the Pirelli is designated as a protected cable and so does not
require to be on an RCD protected circuit.
--
fred
Plusnet - I hope you like vanilla

Andy Burns wrote:
On 02/12/2007 18:42, Andy Wade wrote:

http://www.eca.co.uk/17thEdition/17E...tation.pdf.pdf

So rather than have no definition of a competent person it now has the
definition of ...

"A person who possesses sufficient technical knowledge and
experience for the nature of the electrical work undertaken
and is able at all times to prevent danger, and where
appropriate, injury to themselves and others."

Which looking at the bright side, is actually a definition of competence
that most would recognise, an does not (yet) include requirements to
belong to any particular trade organisation.

--
Cheers,

John.

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

On 2007-12-02 19:17:03 +0000, "Robin"
said:


And here's the ECA's contribution:
http://www.eca.co.uk/17thEdition/17E...tation.pdf.pdf

And the cost-benefit analysis and/or regulatory impact assessment is
where please?

Oh don't worry about that.

This is like Alice in Wonderland - the Queen of Hearts. Sentence
first, trial afterwards.

Work out the legislation that you want then make the RIA fit that
complete with promotions for the civil servants involved. Part P was
done in this way, so this one is a mere bagatelle

John Rumm wrote:

30mA trip seems excessive if the only intention is to protect the wiring
itself and against indirect contact risks (or whatever the new phrase
is) - especially on lighting circuits.

The thinking seems to be a belt & braces approach to avoiding incidents
like the electrified plate rack that killed Jenny Tonge's daughter -
safe zones routing plus either a 30 mA RCD or earthed protection of the
cable to operate the OPD. Where the RCD is used with unprotected cable
it's there to provide additional basic protection (supplementary direct
contact protection in oldspeak) so it does need to be 30 mA.

Apparently a solution NICEIC are proposing at their seminars, for
2-storey houses, is to have a split-load CU (main switch and two 30 mA
RCDs) with two groups of MCBs, one group feeding upstairs lighting and
downstairs power and the other group vice-versa. What fun.

--
Andy

On Sun, 02 Dec 2007 20:28:15 +0000, Andy Burns wrote:

At _ALL_ times?

Wot, even Monday Mornings?

Even Friday afternoons after a session down at The Olde Fuse & Circuit
Breaker?

What is the world coming to?!




--
John Stumbles

Time flies like an arrow
Fruit flies like a banana
Tits like coconuts

Apparently a solution NICEIC are proposing at their seminars, for
2-storey houses, is to have a split-load CU (main switch and two 30 mA
RCDs) with two groups of MCBs, one group feeding upstairs lighting and
downstairs power and the other group vice-versa. What fun.

Anyone have an opportunity to ask them "given the current performance of
RCDs and domestic equipment, what is the estimated increase in the
number/cost of accidents when use of a socket etc downstairs plunges
upstairs into darkness or vice-versa? And the future forecasts bearing
in mind the forecast increase in elderly, single occupancy households?"

--
Robin

On 02/12/2007 20:33, fred wrote:


IIUC the Pirelli is designated as a protected cable and so does not
require to be on an RCD protected circuit.

Ah yes.

In article , Robin
writes

Apparently a solution NICEIC are proposing at their seminars, for
2-storey houses, is to have a split-load CU (main switch and two 30 mA
RCDs) with two groups of MCBs, one group feeding upstairs lighting and
downstairs power and the other group vice-versa. What fun.

Anyone have an opportunity to ask them "given the current performance of
RCDs and domestic equipment, what is the estimated increase in the
number/cost of accidents when use of a socket etc downstairs plunges
upstairs into darkness or vice-versa? And the future forecasts bearing
in mind the forecast increase in elderly, single occupancy households?"

Cue requirements for emergency lighting in domestic installations in
future legislation.
--
fred
Plusnet - I hope you like vanilla

Andy Wade wrote:

Apparently a solution NICEIC are proposing at their seminars, for
2-storey houses, is to have a split-load CU (main switch and two 30 mA
RCDs) with two groups of MCBs, one group feeding upstairs lighting and
downstairs power and the other group vice-versa. What fun.

I think I prefer a dedicated CU for lighting and ancillary circuits with
its own RCD in this circumstance, supplemented with some emergency
lighting in appropriate places.

--
Cheers,

John.

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

On 2007-12-02 13:44:12 +0000, Owain said:

Andy Hall wrote:
Consumer units will need to be redesigned though - e,g, the busbar
arrangements, I would have thought ,because of the extra connections.

Don't the French use double-pole MCBs or RCBOs in their consumer units?

From what I can make out, they are typically groups of single pole MCBs
protected by RCDs. There usually seem to be twice the number as
there are here, probably due to radial circuits.


So handy for isolating le s*n*f*o ...


One would expect to see a lot of them, but they seem to be curiously
absent from the shelves of bricolage places. I think that they are a
secret weapon.

On Sun, 02 Dec 2007 21:33:26 +0000, Andy Wade wrote:

Apparently a solution NICEIC are proposing at their seminars, for
2-storey houses, is to have a split-load CU (main switch and two 30 mA
RCDs) with two groups of MCBs, one group feeding upstairs lighting and
downstairs power and the other group vice-versa. What fun.

Surely that violates the (informal?) principle of least surprise?

--
John Stumbles

Testiculate [v.t]
To wave one's arms around while talking ********.