Is it a mistake that green alone is allowed for insulated MEN connection's?
Or is there a specific reason?
MEN colour if insulated 5.3.5.3
Re: MEN colour if insulated 5.3.5.3
Basically 5.3.5.3 is a 'follower" type clause; in that the colour ID is actually set in another clause (3.8), then repeated in this one.
Logically the two clauses should match.
In fact, the ID requirement (or anything else) shouldn't actually be repeated; because that opens the door for later changes to not be carried through fully, creating a mismatch. Instead 5.3.5.3 should simply refer back to 3.8. But sometimes the Committee take pity on readers, and repeat things.
So my initial thoughts were that in the (gradual) change from 'G' to 'either G or G/Y', and then to 'G/Y;
this one just didn't make the final step.
Which would be a mistake; though of course not a significant one as there can be no bad outcomes of someone uses a green link instead of G/Y.
But after looking back at the history, not so sure.
As far as colour ID for earthing conductors is concerned, history is:
- NZS 3000: 1997; 301.4.3 allowed either G or GY .
- In 2000 (first joint AS/NZS) edition, recommended G/Y but permitted G as alternative.
- There was some amendment of minor details in 2002 & 2003; but no change to the basic requirement.
- 2007 dropped the plain G option.
Bearing in mind that until 1/1/2010; this was guidance only, as the 1997 Regs didn't mandate the relevant clauses.
Which meant that a lot of NZ practitioners simply ignored them; and just kept in doing what they were used to doing.
But from that date, 2007 +A1 was all mandated.
- Again there has been some tweaking of minor details since; but no change to the basic requirement.
But the history for ID of MEN links is different:
- NZS 3000: 1997; 501.9.1.1 allowed either G or GY - for earthing conductors.
(there was no separate rule for the MEN link)
- 3000: 2000, 5.5.3.2 simply pointed to 3.8 for colour ID of earthing conductors; so either G or G/Y was allowed.
However 5.6.5 specified GY for the MEN link; plain G was not permitted.
I don't know why not; but the thinking could well have been that insulated MENs were a recent development so the G option wouldn't be needed. By contrast there would have been plenty of people with legacy sticks of cable that had plain G PECs; and striped sleeving wasn't widely available either).
- 2007 is where it gets a bit strange. While the G option was dropped from 3.8 (as above); it was introduced for MENs.
That seems to defy logic - but presumably was done deliberately.
Hard to believe the (then) Committee reached opposite conclusions at the same time; so there must have been a reason.
I have no idea what that reason may have been; but it's clear that this is not just a case of changing one clause and omitting to change the other.
It might be interesting to find out; but not worth putting great effort into.
Eventually this plain G option will go the way of the dodo.
Logically the two clauses should match.
In fact, the ID requirement (or anything else) shouldn't actually be repeated; because that opens the door for later changes to not be carried through fully, creating a mismatch. Instead 5.3.5.3 should simply refer back to 3.8. But sometimes the Committee take pity on readers, and repeat things.
So my initial thoughts were that in the (gradual) change from 'G' to 'either G or G/Y', and then to 'G/Y;
this one just didn't make the final step.
Which would be a mistake; though of course not a significant one as there can be no bad outcomes of someone uses a green link instead of G/Y.
But after looking back at the history, not so sure.
As far as colour ID for earthing conductors is concerned, history is:
- NZS 3000: 1997; 301.4.3 allowed either G or GY .
- In 2000 (first joint AS/NZS) edition, recommended G/Y but permitted G as alternative.
- There was some amendment of minor details in 2002 & 2003; but no change to the basic requirement.
- 2007 dropped the plain G option.
Bearing in mind that until 1/1/2010; this was guidance only, as the 1997 Regs didn't mandate the relevant clauses.
Which meant that a lot of NZ practitioners simply ignored them; and just kept in doing what they were used to doing.
But from that date, 2007 +A1 was all mandated.
- Again there has been some tweaking of minor details since; but no change to the basic requirement.
But the history for ID of MEN links is different:
- NZS 3000: 1997; 501.9.1.1 allowed either G or GY - for earthing conductors.
(there was no separate rule for the MEN link)
- 3000: 2000, 5.5.3.2 simply pointed to 3.8 for colour ID of earthing conductors; so either G or G/Y was allowed.
However 5.6.5 specified GY for the MEN link; plain G was not permitted.
I don't know why not; but the thinking could well have been that insulated MENs were a recent development so the G option wouldn't be needed. By contrast there would have been plenty of people with legacy sticks of cable that had plain G PECs; and striped sleeving wasn't widely available either).
- 2007 is where it gets a bit strange. While the G option was dropped from 3.8 (as above); it was introduced for MENs.
That seems to defy logic - but presumably was done deliberately.
Hard to believe the (then) Committee reached opposite conclusions at the same time; so there must have been a reason.
I have no idea what that reason may have been; but it's clear that this is not just a case of changing one clause and omitting to change the other.
It might be interesting to find out; but not worth putting great effort into.
Eventually this plain G option will go the way of the dodo.
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