Alterations to cables with green sheathed or bare earths

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JamieP
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Alterations to cables with green sheathed or bare earths

Post by JamieP »

Is my thinking correct that there is no complaint way to make alterations and move or reroute such cables?

Obviously the parts already in service may remain in service but any part I try reroute or alter from one position on a wall to another then must comply with 3000

Because 5.3.2.4 and 5.3.2.5 I can't see how I could do so compliantly other than a join with new cable from the point I want to alter

The bare earth within the altered cable wouldn't comply because not insulated and I can't insulate it without removing the sheath of the altered section which just creates more problems

And 3.8.2 doesn't allow me to identify the green insulation as what it needs to be

Any input?
AlecK
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Re: Alterations to cables with green sheathed or bare earths

Post by AlecK »

Your interpretation is correct in that it is non-compliant to install bare PECs [5.3.2.4].
Also that 3.8.1 forbids use of green-only to identify PECs by colour - although 5.3.5.3 permits it.
And that these rules have an effect on re-routing parts of existing circuits

WRT sleeving; 3.8.2 does not prohibit sleeving a green as G/Y..
3.8.2 is in 3 parts, all of which are permissive rather than restrictive.
(a) allows a black or light blue conductor to be sleeved as an active.
(b) & (c) allow colours other than those listed in each case to be sleeved as a neutral or earth
But (b) does not forbid sleeving a blue to black (to comply with ESRs requirement that domestic Ns must be black);
and (c) does not prohibit sleeving a green with G/Y.

Moving to para 3, which requires the colour ID of earthing conductorts to be along the entire length;
the wording does not prohibit the sleeving of a green earth using G/Y at only the terminations.

In fact the only prohibition in all of 3.8.2 is para 4, which prohibits re-purposing a green, yellow, or G/Y conductor as active or neutral.

Note that 2018 edition not only makes specific allowance for using G/Y sleeving on green or bare PECs;
but actually makes it mandatory when joining new cable to existing.
Also when connecting to existing cables with yellow actives, can & must sleeve with an "active" colour.
JamieP
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Re: Alterations to cables with green sheathed or bare earths

Post by JamieP »

Doesn't 5.3.5.3 only apply to MEN links and not PECs for the use of green? So no conflict as 3.8.1 doesn't specify color for MEN links?

And also, they way I read 3.8.2 is that it allows use of sleeving or other means to identify, so for option (c) allows me to use green/yellow to identify conductors as earths within multicore cables but it specifically says, I can only do it to conductors that are not, green, yellow or green/yellow?

But re reading what you said again I se what you mean, if I applied the same logic as above I wouldn't be able to sleeve a light blue as a black to comply with ESR20, I see what you mean

Many thanks as per usual Alec
AlecK
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Re: Alterations to cables with green sheathed or bare earths

Post by AlecK »

WRT 5.3.5.3; yes it's only for the MEN link- and really just an oversight I believe.

WRT wording of 3.8.2 ), the word "only"does not appear.
So the effect is that the stated options are specifically permitted, and other options are not prohibited.

For (c); the specifically permitted options include sleeving actives & neutrals as earths.
There's no logical reason to forbid putting a G/Y sleeve onto a green conductor.

The whole point is to clearly identify the conductor's function; and the governing rule is that G/Y can't be re-purposed - can only be used for earthing functions. In fact G/Y can't be used for other purposes even if colour is not the chosen method of ID.
This priority of identification is not because earths are safe to work on; but on contrary because they are so essential to safety that they should be left alone.
G/Y has taken over from plain G due to prevalence of R - G colourblindness ( so of it's bi-coloured, it's an earth).

Personally I'd like to see this re-written by listing what's not permitted.
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Satobsat
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Re: Alterations to cables with green sheathed or bare earths

Post by Satobsat »

Hi AlecK
"the governing rule is that G/Y can't be re-purposed - can only be used for earthing functions. In fact G/Y can't be used for other purposes even if colour is not the chosen method of ID."
Was there an overlap period when 2C+E TPS was produced with G/Y insulation alongside the allowance of sleeving the earth red?
I think I have only ever seen green insulated cores sleeved red in the past.
I came across a two way strap the other week that was run in 2.5mm² 2C+E TPS with a G/Y core, so possibly a DIY job as no sleeving was to be seen anywhere.
Just wondering if the rules changed at the same time as the G/Y insulation was introduced.
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Re: Alterations to cables with green sheathed or bare earths

Post by Satobsat »

Found this:

AS/NZS 3000:2018 1.7.2 f Live conductors shall not be insulated or sheathed with green, yellow or green/yellow combination colours in installation wiring.
Exception: In New Zealand only, there is no restriction on sheath colour

But I think this applies to outer sheathing only?
AlecK
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Re: Alterations to cables with green sheathed or bare earths

Post by AlecK »

As an apprentice in the '70s, I never saw 1.0 mm2 3c used for straps, we always sleeved the green(and the black) with red.
I don't know exactly when TPS for NZ market started being made with G/Y for the PEC.
But would have thought it was after the rule changes that stopped us from re-purposing the PEC for other duties.
Probably around the same time as the rule specifying colour ID introduced G/Y.

1993 Regs [61] restricted G & G/Y to only earthing functions; and cited ECP 28 as means of compliance (so not mandatory).
The ECP allowed for use of insulated sleeving.

1997 Regs [71] the same; until Amended 1999 to cite NZS 3000: 1997
which specified both colours, but didn't restrict re-purposing[301.4.3].

Further Amended 2002 to cite AS/NZS 3000: 2000
This included the first prohibition on sleeving G or G/Y as live conductors [3.8.1]
Bearing in mind that most of "3000" was not mandated; only certain clauses - not including this one.
So many practitioners would have cheerfully carried in in their old ways, on basis of "that rule isn't mandated, so i don't have to follow it".

So it wasn't until 1 April 2010, with ESRs coming into force, that sleeving PECs as live became absolutely and un-arguably prohibited.

---------------

Correct that the NZ-only but of 1.7.2 (repeated in 3.8.1) in 2018 edition applies to sheath colour only.
At that time there was TPS around with (very pale) pale green sheath (similar to the mauve used to indicate can be placed next to polystyrene foam). Not sure whether that's syill available.
There's also the now-common yellow sheath used to indicate a 3C TPS with no PEC
The Ozzies had a bit of knee-jerk reaction to these - they seem to have a fairly low opinion of their tradespeople's intelligence.

Which br8ngs us to the reason for the restrictions.
Many seem to think it's so we know which is the earth, and is safe to cut.
In fact it's the opposite; it's to clealy iD the conductors that serve a safety function so MUST NOT be interfered with.
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