Wiring conventions
 

Hello

Following on from my recent installation of an extractor fan.

The fan I fitted requires 4 connections: neutral, permanent live, and two
switched lives. I bought myself a length of 4 core cable of the required
rating but I'm confused about which colours to use and whether there might
be a different coloured cable that I should have used.

The cable that I bought has inners coloured brown, blue, black and
green/yellow. I wired the blue to the neutral and the brown to the permanent
live - leaving the black and green/yellow for the two switched lives. I have
a 3 pole isolator on all of the live cables, but even so, I'm not
comfortable with having a green/yellow for a potentially live cable and I'd
like to find a solution to this asap.

What is the normal convention in these situations - is there a 4 core cable
with different colours made specifically for this type of installation?

Thanks
Thomas

Wiring conventions
 

Thomas wrote:

The cable that I bought has inners coloured brown, blue, black and
green/yellow. I wired the blue to the neutral and the brown to the permanent
live - leaving the black and green/yellow for the two switched lives. I have
a 3 pole isolator on all of the live cables, but even so, I'm not
comfortable with having a green/yellow for a potentially live cable and I'd
like to find a solution to this asap.

You're right to be uncomfortable, you're NOT allowed to use green/yellow
as a live, even if you sleeve it in brown. It can only be used as "earth".

What is the normal convention in these situations - is there a 4 core cable
with different colours made specifically for this type of installation?

You can get a 5 core flex suitable for your purpose

http://www.tlc-direct.co.uk/Main_Ind...e_3/index.html

Higher number of cores may be numbered instead of coloured.

Wiring conventions
 

On 11/09/2012 16:29, Thomas wrote:
Hello

Following on from my recent installation of an extractor fan.

The fan I fitted requires 4 connections: neutral, permanent live, and two
switched lives. I bought myself a length of 4 core cable of the required

Sounds like your bought one wire too few...

rating but I'm confused about which colours to use and whether there might
be a different coloured cable that I should have used.

Blue is neutral, while brown, and black are "live" colours (in the
harmonised colour scheme). Green/yellow is earth.

The cable that I bought has inners coloured brown, blue, black and
green/yellow. I wired the blue to the neutral and the brown to the permanent
live - leaving the black and green/yellow for the two switched lives. I have
a 3 pole isolator on all of the live cables, but even so, I'm not
comfortable with having a green/yellow for a potentially live cable and I'd
like to find a solution to this asap.

What is the normal convention in these situations - is there a 4 core cable
with different colours made specifically for this type of installation?

Its very bad practice to re-purpose a green/yellow CPC in a cable/flex.

The typical 5 core flex used by central heating installers may be more
appropriate. Or I would probably run a length of T&E and one of 3&E to
give five cores plus earth.



--
Cheers,

John.

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

Wiring conventions
 

John Rumm wrote:
On 11/09/2012 16:29, Thomas wrote:
Hello

Following on from my recent installation of an extractor fan.

The fan I fitted requires 4 connections: neutral, permanent live,
and two switched lives. I bought myself a length of 4 core cable of
the required

Sounds like your bought one wire too few...

rating but I'm confused about which colours to use and whether
there might be a different coloured cable that I should have used.

Blue is neutral, while brown, and black are "live" colours (in the
harmonised colour scheme). Green/yellow is earth.

The cable that I bought has inners coloured brown, blue, black and
green/yellow. I wired the blue to the neutral and the brown to the
permanent live - leaving the black and green/yellow for the two
switched lives. I have a 3 pole isolator on all of the live cables,
but even so, I'm not comfortable with having a green/yellow for a
potentially live cable and I'd like to find a solution to this asap.

What is the normal convention in these situations - is there a 4
core cable with different colours made specifically for this type
of installation?

Its very bad practice to re-purpose a green/yellow CPC in a
cable/flex.
The typical 5 core flex used by central heating installers may be more
appropriate. Or I would probably run a length of T&E and one of 3&E to
give five cores plus earth.

As both John and Andy have pointed out you should not use the green/yellow
for anything other than "earth". It's also bad practice not to run an earth
out with all the other cores even for something that will not be earthed.
You "park" the earth core in a piece of strip connector inside the fan.

As they both said, 5 core flex is one suitable answer.

--
Adam

Wiring conventions
 

In article , John Rumm wrote:
On 11/09/2012 16:29, Thomas wrote:

The fan I fitted requires 4 connections: neutral, permanent live, and two
switched lives. I bought myself a length of 4 core cable of the required

Sounds like your bought one wire too few...

If it really doesn't need an earth (double insulated), and he can find four
core in blue, brown, grey and black, that should be enough.


Its very bad practice to re-purpose a green/yellow CPC in a cable/flex.

While not disagreeing with you, I notice that Googling for "For green and
yellow conductors in multicore cables, overmarking in another colour at
terminations is permitted. This is prohibited for single core green-and-yellow
conductors." has a few hits.

http://www.simptech-solutions.com/eb...egulations.pdf

Wiring conventions
 

Alan Braggins wrote:
In article , John
Rumm wrote:
On 11/09/2012 16:29, Thomas wrote:

The fan I fitted requires 4 connections: neutral, permanent live,
and two switched lives. I bought myself a length of 4 core cable
of the required

Sounds like your bought one wire too few...

If it really doesn't need an earth (double insulated), and he can
find four core in blue, brown, grey and black, that should be enough.


Its very bad practice to re-purpose a green/yellow CPC in a
cable/flex.

While not disagreeing with you, I notice that Googling for "For green
and yellow conductors in multicore cables, overmarking in another
colour at terminations is permitted. This is prohibited for single
core green-and-yellow conductors." has a few hits.

http://www.simptech-solutions.com/eb...egulations.pdf


Reg 514.4.2

The bi-colour combination green-and-yellow shall be used exclusively for the
identification of a protective conductor and this combination shall not be
used for any other purpose"

--
Adam

Wiring conventions
 

On Tuesday, September 11, 2012 4:28:49 PM UTC+1, Thomas wrote:
Hello



Following on from my recent installation of an extractor fan.



The fan I fitted requires 4 connections: neutral, permanent live, and two

switched lives. I bought myself a length of 4 core cable of the required

rating but I'm confused about which colours to use and whether there might

be a different coloured cable that I should have used.



The cable that I bought has inners coloured brown, blue, black and

green/yellow. I wired the blue to the neutral and the brown to the permanent

live - leaving the black and green/yellow for the two switched lives. I have

a 3 pole isolator on all of the live cables, but even so, I'm not

comfortable with having a green/yellow for a potentially live cable and I'd

like to find a solution to this asap.



What is the normal convention in these situations - is there a 4 core cable

with different colours made specifically for this type of installation?



Thanks

Thomas


If you dont have enough conductors, just use 2 T&E cables - or 3&e + T&E or whatever you need.


NT

Wiring conventions
 

In article , ARW wrote:
Alan Braggins wrote:
In article , John
Rumm wrote:

Its very bad practice to re-purpose a green/yellow CPC in a
cable/flex.

While not disagreeing with you, I notice that Googling for "For green
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
and yellow conductors in multicore cables, overmarking in another
colour at terminations is permitted. This is prohibited for single
core green-and-yellow conductors." has a few hits.

http://www.simptech-solutions.com/eb...egulations.pdf


Reg 514.4.2

The bi-colour combination green-and-yellow shall be used exclusively for the
identification of a protective conductor and this combination shall not be
used for any other purpose"

I've not got the actual regs, only seen bits of guides to them.

http://books.google.co.uk/books?id=q...ctors.&f=false

for example says "prohibited for single core green-and-yellow conductors
(Regulation 514.4.2)"

Wiring conventions
 

wrote in message
...

If you dont have enough conductors, just use 2 T&E cables - or 3&e + T&E
or whatever you need.


The problem is that there is a silicon grommet at the entrnce to the unit
which is designed to seal around a single inlet cable. Using multiple cables
would provide a moisture ingress path :-(

Thanks
Thomas

Wiring conventions
 

In article ,
Thomas wrote:
The cable that I bought has inners coloured brown, blue, black and
green/yellow. I wired the blue to the neutral and the brown to the
permanent live - leaving the black and green/yellow for the two
switched lives. I have a 3 pole isolator on all of the live cables, but
even so, I'm not comfortable with having a green/yellow for a
potentially live cable and I'd like to find a solution to this asap.

You've bought the wrong cable. It is presumable a flex since it has
sleeved earth? It is flex designed for three phase stuff by the colours.
And yellow/green is for earth *only*.

Any decent wholesaler will have 4 core plus earth flex. Like this:-

http://www.tlc-direct.co.uk/Main_Ind...e_3/index.html

If you don't need the earth, leave it unused, but taped safely out of the
way.

--
*Never underestimate the power of stupid people in large groups.

Dave Plowman London SW
To e-mail, change noise into sound.

Wiring conventions
 

Dave Plowman (News) wrote:

In article ,
Thomas wrote:
The cable that I bought has inners coloured brown, blue, black and
green/yellow. I wired the blue to the neutral and the brown to the
permanent live - leaving the black and green/yellow for the two
switched lives. I have a 3 pole isolator on all of the live cables, but
even so, I'm not comfortable with having a green/yellow for a
potentially live cable and I'd like to find a solution to this asap.

You've bought the wrong cable. It is presumable a flex since it has
sleeved earth? It is flex designed for three phase stuff by the colours.
And yellow/green is for earth *only*.

Any decent wholesaler will have 4 core plus earth flex. Like this:-

http://www.tlc-direct.co.uk/Main_Ind...e_3/index.html

If you don't need the earth, leave it unused, but taped safely out of the
way.


It may be considered good practise to earth unused conductors.

Not sure if it's a reg or not, I am in a meeting right now and my red book's
at home.

--
Tim Watts

Wiring conventions
 

Tim Watts wrote:
Dave Plowman (News) wrote:

In article ,
Thomas wrote:
The cable that I bought has inners coloured brown, blue, black and
green/yellow. I wired the blue to the neutral and the brown to the
permanent live - leaving the black and green/yellow for the two
switched lives. I have a 3 pole isolator on all of the live
cables, but even so, I'm not comfortable with having a
green/yellow for a potentially live cable and I'd like to find a
solution to this asap.

You've bought the wrong cable. It is presumable a flex since it has
sleeved earth? It is flex designed for three phase stuff by the
colours. And yellow/green is for earth *only*.

Any decent wholesaler will have 4 core plus earth flex. Like this:-

http://www.tlc-direct.co.uk/Main_Ind...e_3/index.html

If you don't need the earth, leave it unused, but taped safely out
of the way.


It may be considered good practise to earth unused conductors.

Not sure if it's a reg or not, I am in a meeting right now and my red
book's at home.

http://wiki.diyfaq.org.uk/index.php?...ile:Img206.jpg

Now Reg number 131.2.1 in the 17th.

Of course that would never happen. In real life all the unused cores would
be shoved into the same piece of strip connector with the earth.

--
Adam

Wiring conventions
 

On 15/09/2012 12:29, ARW wrote:
http://wiki.diyfaq.org.uk/index.php?...ile:Img206.jpg

Now Reg number 131.2.1 in the 17th.

Of course that would never happen. In real life all the unused cores would
be shoved into the same piece of strip connector with the earth.

File:Img206.jpg

No file by this name exists.

Andy

Wiring conventions
 

Andy Champ wrote:
On 15/09/2012 12:29, ARW wrote:
http://wiki.diyfaq.org.uk/index.php?...ile:Img206.jpg

Now Reg number 131.2.1 in the 17th.

Of course that would never happen. In real life all the unused
cores would be shoved into the same piece of strip connector with
the earth.

File:Img206.jpg

No file by this name exists.#

It does. Now at

http://i428.photobucket.com/albums/q...020/img206.jpg


due to copyright reasons.



--
Adam

Wiring conventions
 

Adam wrote:

Reg 514.4.2

The bi-colour combination green-and-yellow shall be used exclusively for
the identification of a protective conductor and this combination shall
not be used for any other purpose"

I would suggest that this regulation specifically refers to the visible
green/yellow colour combination of the conductor. If the visible colours of
a conductor are green/yellow, then that 'exclusively identifies that
conductor as a protective conductor'.

However, if the exposed green/yellow conductor of a multicore cable is fully
oversheathed or sleeved in another colour (e.g. brown) at the terminations,
then IMO, the new designation for that conductor would not contravene the
regulations.

It's not that different from oversheathing the blue neutral in a switch drop
with brown sleeving to redesignate it as a live conductor.
--
Interloper

Wiring conventions
 

Interloper wrote:

Adam wrote:

Reg 514.4.2

The bi-colour combination green-and-yellow shall be used exclusively for
the identification of a protective conductor and this combination shall
not be used for any other purpose"

I would suggest that this regulation specifically refers to the visible
green/yellow colour combination of the conductor. If the visible colours
of a conductor are green/yellow, then that 'exclusively identifies that
conductor as a protective conductor'.

However, if the exposed green/yellow conductor of a multicore cable is
fully oversheathed or sleeved in another colour (e.g. brown) at the
terminations, then IMO, the new designation for that conductor would not
contravene the regulations.

It's not that different from oversheathing the blue neutral in a switch
drop with brown sleeving to redesignate it as a live conductor.

Hang about - whilst I cannot put my finger on the reg this second, I believe
that using a green/yellow conductor for any other purpose is absolutely
verboten.

Give me a few hours - I think I can back that up...

But common sense wise - what if someone cuts the cable later, determines
an apparant CPC and bonds it to something exposed?


--
Tim Watts Personal Blog: http://www.dionic.net/tim/

"She got her looks from her father. He's a plastic surgeon."

Wiring conventions
 

In message , Tim Watts
writes

Hang about - whilst I cannot put my finger on the reg this second, I believe
that using a green/yellow conductor for any other purpose is absolutely
verboten.


There is of course an exemption for this if you are a plumber, then the
green/yellow, or even just the bare copper earth lead can be, and is,
used for a live return.






Please don't take the above seriously.

--
Bill
( A different one )

Wiring conventions
 

"Tim Watts" wrote:

Interloper wrote:

Adam wrote:

Reg 514.4.2

The bi-colour combination green-and-yellow shall be used exclusively for
the identification of a protective conductor and this combination shall
not be used for any other purpose"

I would suggest that this regulation specifically refers to the visible
green/yellow colour combination of the conductor. If the visible colours
of a conductor are green/yellow, then that 'exclusively identifies that
conductor as a protective conductor'.

However, if the exposed green/yellow conductor of a multicore cable is
fully oversheathed or sleeved in another colour (e.g. brown) at the
terminations, then IMO, the new designation for that conductor would not
contravene the regulations.

It's not that different from oversheathing the blue neutral in a switch
drop with brown sleeving to redesignate it as a live conductor.

Hang about - whilst I cannot put my finger on the reg this second, I
believe
that using a green/yellow conductor for any other purpose is absolutely
verboten.

You might be right, but I couldn't find a regulation prohibiting the
reassignment of the green/yellow conductor in a multicore cable.

I think you'll find that using the combination green/yellow *COLOUR* for
anything other than a protective conductor is 'absolutely verboten' (or
'absolutely forbidden', once the UK is out of the EU). However, reassigning
the green/yellow conductor of a multicore cable (*NOT* a single core
conductor, which is forbidden), does not appear to contravene the regs.

Reassignment of a conductor at the termination using tape, sleeving, or
alphanumeric identifiers takes precedence over the original core colour
(although it would be good practice to also oversleeve a reassigned
green/yellow conductor in a multicore cable when alphanumeric identifiers
are being used).

Give me a few hours - I think I can back that up...

OK, over to you, then ;-)

But common sense wise - what if someone cuts the cable later, determines
an apparent CPC and bonds it to something exposed?

What, without checking/testing the 'apparent aspect of their CPC
observation? I guess the protective device/mcb/rcd will trip on
re-energisation :-)

If someone 'cuts the cable later', they should be a qualified electrician
and know what they're doing. If they are remaking the termination for some
reason, they should at least notice that the green/yellow conductor has been
reassigned at the old termination. If they're simply reusing the cable for
something else, then any previous reassignments at the terminations would be
irrelevant.


This extract is taken from an ECA Guide to the 17th Edition IEE Wiring
Regulations:

"D 3.1 Principle of required identification (514.3.1)

It is most important to understand the principle behind the drafting of the
17th Edition in respect of cable identification. Cable cores shall be
identifiable at their terminations either by colour or by alphanumeric
characters. While this has not changed from the 16th Edition it is worth
discussing the principles.

It is noted that cores should preferably be identifiable throughout their
length. For many applications coloured cables, either single- or multicore,
will be used and these cables are obviously identified throughout their
length. However, in many other applications installers will need to make
use of this Regulation (514.3.1) for overmarking at terminations. The
principles and applications of identification are now discussed with the use
of diagrams.

[sorry, can't post the diagrams]

Figure D 3.1 shows the principle of identification where colours are used,
i.e. marking by colour at all terminations and preferably throughout the
length.

In Figure D 3.1 marking throughout the length is not used and single core
cables have been used. It should be noted that the colour of the cables
originally used is not important and overmarking by tape or similar takes
precedence.

Building on this principle, Figure D 3.2 shows the principle of
identification where alphanumeric identification is used.

It is perhaps more obvious now that marking throughout the length is not
necessary. It should be noted that the colour of the cables originally used
is not important and overmarking takes precedence. This principle holds
whatever the colour of cores of the original cable, and applies at
terminations by coloured tapes or by characters.

In summary, an important principle is established in that, wherever marking
at terminations by either tapes, lettering or numbering is used, the
original cable colours must be ignored; this can be against your gut feeling
but you must get used to it!

Common examples and applications where identification is only practised at
terminations include the following:

- Multicore cables with more than five cores.
- MICC cables.
- Control applications wired in single-core conductors.
- Applications where coloured cable is not available, including
connections to large generators or transformers, where often only black
cable is available.

It should now be established that installers may wish to use any single
cable colour, or combination of colours, and overmark at terminations, and
this is not considered a lesser option. For green-and-yellow conductors in
multicore cables, overmarking in another colour at terminations is
permitted. Overmarking at terminations is prohibited for single-core
green-and-yellow conductors."

--
Interloper

Wiring conventions
 

En el artículo , Tim Watts
escribió:

But common sense wise - what if someone cuts the cable later, determines
an apparant CPC and bonds it to something exposed?

The same argument applies - what if it's a switch wire and the blue wire
is sheathed brown at both ends, but not where it is cut?

It's an interesting question.

--
(\_/)
(='.'=)
(")_(")

Wiring conventions
 

Interloper wrote:

"Tim Watts" wrote:

Hang about - whilst I cannot put my finger on the reg this second, I
believe
that using a green/yellow conductor for any other purpose is absolutely
verboten.

You might be right, but I couldn't find a regulation prohibiting the
reassignment of the green/yellow conductor in a multicore cable.

I think you'll find that using the combination green/yellow *COLOUR* for
anything other than a protective conductor is 'absolutely verboten' (or
'absolutely forbidden', once the UK is out of the EU). However,
reassigning the green/yellow conductor of a multicore cable (*NOT* a
single core conductor, which is forbidden), does not appear to contravene
the regs.

Reassignment of a conductor at the termination using tape, sleeving, or
alphanumeric identifiers takes precedence over the original core colour
(although it would be good practice to also oversleeve a reassigned
green/yellow conductor in a multicore cable when alphanumeric identifiers
are being used).

Give me a few hours - I think I can back that up...

OK, over to you, then ;-)

BS7671:2008 17th Edition pre Amendment 1:

514.4.2 (Excerpt):

"The bi-colour combination green-and-yellow shall be used exclusively for
identification of a protective conductor and this combination shall not be
used for any other purpose.

Single-core cables that are coloured green-and-yellow throughout their
length shall only be used as a protective conductor and shall not be over-
marked at their terminations, except as premitted by Regulation 514.4.3..."

Yes, it makes a big point of single-cores but the overall meaning is pretty
clear - it would be a brave man that would argue against that. IMHO the
first sentence covers all eventualities and the second is just
reinforcement.


Reg 514.4.3 refers to PEN conductors which are G/Y with blue sleeves at the
terminations.


But common sense wise - what if someone cuts the cable later, determines
an apparent CPC and bonds it to something exposed?

What, without checking/testing the 'apparent aspect of their CPC
observation? I guess the protective device/mcb/rcd will trip on
re-energisation :-)

If someone 'cuts the cable later', they should be a qualified electrician
and know what they're doing. If they are remaking the termination for some
reason, they should at least notice that the green/yellow conductor has
been
reassigned at the old termination. If they're simply reusing the cable
for something else, then any previous reassignments at the terminations
would be irrelevant.

Yes - but even qualified electricians don't like being caught out with
extreme weirdness ;- This is why there are colour standards - which are
otherwise arguably irrelevent to safety as the electrons don;t really care.



It should now be established that installers may wish to use any single
cable colour, or combination of colours, and overmark at terminations, and
this is not considered a lesser option. For green-and-yellow conductors
in multicore cables, overmarking in another colour at terminations is
permitted. Overmarking at terminations is prohibited for single-core
green-and-yellow conductors."


That's their view, but I don't much like it - I think it is argued on the
letter rather than the spirit of 514.4.2

--
Tim Watts Personal Blog: http://www.dionic.net/tim/

"History will be kind to me for I intend to write it."

Wiring conventions
 

Mike Tomlinson wrote:

En el artÃ*culo , Tim Watts
escribió:

But common sense wise - what if someone cuts the cable later, determines
an apparant CPC and bonds it to something exposed?

The same argument applies - what if it's a switch wire and the blue wire
is sheathed brown at both ends, but not where it is cut?

It's an interesting question.


Not really - at least not these days. 17th basically states that "neutral"
is to be considered a live conductor, as opposed to what we all call live
which is now called "line" (rather than "phase" like it used to be).

In other words, neutral is regarded as dangerous and not to be left
uninsulated, exposed, connected to random metalwork etc.

In this repsect the CPC has a very special status which is why it's
important to avoid mistakes of this nature.


--
Tim Watts Personal Blog: http://www.dionic.net/tim/

"History will be kind to me for I intend to write it."

Wiring conventions
 

En el artículo , Tim Watts
escribió:

Not really - at least not these days. 17th basically states that "neutral"
is to be considered a live conductor

Thanks for that.

--
(\_/)
(='.'=)
(")_(")

Wiring conventions
 

"Tim Watts" wrote

Give me a few hours - I think I can back that up...

OK, over to you, then ;-)

BS7671:2008 17th Edition pre Amendment 1:

514.4.2 (Excerpt):

"The bi-colour combination green-and-yellow shall be used exclusively for
identification of a protective conductor and this combination shall not be
used for any other purpose."

This rule is referring specifically and only to the colour identification of
a conductor (at the termination point). If the conductor colour is the
bi-colour combination of green-and-yellow , then that conductor must be a
CPC. The bi-colour combination of green-and-yellow shall not be used for
any other purpose. However, this rule has no bearing on the reassignment of
a green/yellow conductor by oversleeving with a different colour at the
termination points.

Single-core cables that are coloured green-and-yellow throughout their
length shall only be used as a protective conductor and shall not be over-
marked at their terminations, except as permitted by Regulation
514.4.3..."

This rule specifically precludes the reassignment of a single-core
green/yellow conductor for any other purpose. I suggest this rule exists to
ensure reassignment of a green/yellow conductor will only occur in a
multicore cable. This rule would be superfluous if the reassignment of a
green/yellow conductor was not permitted under any circumstances. The rule
could have been made much clearer.

Yes, it makes a big point of single-cores but the overall meaning is
pretty
clear - it would be a brave man that would argue against that. IMHO the
first sentence covers all eventualities and the second is just
reinforcement.

The first rule (sentence) is very clear about the use of the bi-colour
combination of green-and-yellow only. It refers just to the colour
identification, and not to conductor reassignment.

Yes - but even qualified electricians don't like being caught out with
extreme weirdness ;- This is why there are colour standards - which are
otherwise arguably irrelevant to safety as the electrons don't really
care.

IMO, the colour standards are now a mess that frequently has to be clarified
by the use of additional alpha-numerical identifiers.. The latest colours
were chosen as the EU standard in such a way that no country could be seen
to be at an advantage as a consequence of the colour standard they were
already using. At least the UK was instrumental in persuading the other
European countries to adopt three different phase colours (brown, black and
grey, rather than brown, black, black). It's taken since 1969 to agree and
implement these colour changes!

--
Interloper

Wiring conventions
 

Interloper wrote:

"Tim Watts" wrote

Give me a few hours - I think I can back that up...

OK, over to you, then ;-)

BS7671:2008 17th Edition pre Amendment 1:

514.4.2 (Excerpt):

"The bi-colour combination green-and-yellow shall be used exclusively for
identification of a protective conductor and this combination shall not
be used for any other purpose."

This rule is referring specifically and only to the colour identification
of
a conductor (at the termination point). If the conductor colour is the
bi-colour combination of green-and-yellow , then that conductor must be a
CPC. The bi-colour combination of green-and-yellow shall not be used for
any other purpose. However, this rule has no bearing on the reassignment
of
a green/yellow conductor by oversleeving with a different colour at the
termination points.

Single-core cables that are coloured green-and-yellow throughout their
length shall only be used as a protective conductor and shall not be
over- marked at their terminations, except as permitted by Regulation
514.4.3..."

This rule specifically precludes the reassignment of a single-core
green/yellow conductor for any other purpose. I suggest this rule exists
to ensure reassignment of a green/yellow conductor will only occur in a
multicore cable. This rule would be superfluous if the reassignment of a
green/yellow conductor was not permitted under any circumstances. The
rule could have been made much clearer.

Yes, it makes a big point of single-cores but the overall meaning is
pretty
clear - it would be a brave man that would argue against that. IMHO the
first sentence covers all eventualities and the second is just
reinforcement.

The first rule (sentence) is very clear about the use of the bi-colour
combination of green-and-yellow only. It refers just to the colour
identification, and not to conductor reassignment.

It's a compelling argument - I'm inclined to change my POV about the
interpretation. I still maintain that it's a bad idea though.

Yes - but even qualified electricians don't like being caught out with
extreme weirdness ;- This is why there are colour standards - which are
otherwise arguably irrelevant to safety as the electrons don't really
care.

IMO, the colour standards are now a mess that frequently has to be
clarified
by the use of additional alpha-numerical identifiers.. The latest colours
were chosen as the EU standard in such a way that no country could be seen
to be at an advantage as a consequence of the colour standard they were
already using. At least the UK was instrumental in persuading the other
European countries to adopt three different phase colours (brown, black
and
grey, rather than brown, black, black). It's taken since 1969 to agree
and implement these colour changes!


Yep.

--
Tim Watts Personal Blog: http://www.dionic.net/tim/

"A fanatic is one who can't change his mind and won't change the subject."

Wiring conventions
 

"Tim Watts" wrote:

Interloper wrote:

The first rule (sentence) is very clear about the use of the bi-colour
combination of green-and-yellow only. It refers just to the colour
identification, and not to conductor reassignment.

It's a compelling argument - I'm inclined to change my POV about
the interpretation.

I still maintain that it's a bad idea though.

I agree it's not the perfect solution, but as a last resort when you have
run out of cores, it's useful to know that reassignment of the green/yellow
conductor in a multicore cable is permitted under the IEE Regulations.
Providing, of course, that the integrity of the earthing system is not
compromised as a consequence of the reassignment.
--
Interloper