People using the Yellow/Green core in flex as a live conducter!

Status
Not open for further replies.
eveares

eveares

Joined
28 Jul 2012
Messages
1,351
Reaction score
55
Location
Surrey
Country
United Kingdom
Under Regulation 411.3.1.1 (Page 55 of the 17th edition of BS7671 Amendment 3), as quoted;

A circuit protective conductor shall be run to and terminated at each point in wiring and at each accessory except a lampholder having no exposed-conductive-parts and suspended from such a point.
Click to expand...

It is clear that that a CPC must be included in all fixed wiring except for Class 2 lamp holders, even if it is a Class 2 device at the other end.

Yet people still use the "earth" core in flex as a live conductor!

Today I found out that the HW cylinder stat at my grandparents is wired in 3 core with the "earth" core being used for HW Off. (Y Plan/3 Port valve). Same for the old CH thermostat.

What code would you give such a discovery during a EICR?

Regards: Elliott.
 
That's nothing. The rewire we did in the weeks leading up to Christmas had the 2-wire stat wired in T+E. Fine you say? Nooo, they'd given it a neutral it didn't need, a perm live and used the bare cpc as the switched line.

And if that wasn't bad enough, they'd sleeved the core GY! To say I was less than impressed is an understatement.

Most you're gonna get for your example is a C2 - Mine, gonna be a C1. Don't forget the cylinder stat will likely, although not the best path, have a degree of earth continuity through it's contact with the bonded cylinder. There's multiple opportunities for the tank to be connected to 'earth' - boiler cpc, main gas bond (via the boiler pipework), main water supplementary bond, immersion cpc.

Thermostat is a bit different depending on the cable route but I can't see it going any higher than a C2. It's no more dangerous than a twin+no earth as still found in many lighting circuits.

You'd obviously hope the ends were flagged (correctly) but this rarely happens.
 
eveares said:
Under Regulation 411.3.1.1 ... It is clear that that a CPC must be included in all fixed wiring except for Class 2 lamp holders, even if it is a Class 2 device at the other end.
Click to expand...
Not necessarily. The requirement is only for a CPC to be run to each 'point'/accessory. If more than one cable goes to that point/accessory (e.g. to a ceiling rose) then the regulation is satisfied if only one of those cables carries a CPC.
eveares said:
Yet people still use the "earth" core in flex as a live conductor! .... Today I found out that the HW cylinder stat at my grandparents is wired in 3 core with the "earth" core being used for HW Off. (Y Plan/3 Port valve). Same for the old CH thermostat. .... What code would you give such a discovery during a EICR?
Click to expand...
Assuming you are still talking about flex (with an G/Y insulated 'earth' core) that, in itself, is compliant with regs provided that the G/Y is sleeved accordingly (presumably brown) at both ends.

Hence, what you describe might be non-compliant (in terms of 411.3.1.1) if nothing was supplying a CPC to the 'point'/accessory, but an over-sleeved G/Y would not, in itself, be non-compliant.

There are only two things that, per regs, you can't do - (1) use the bare CPC of, say, T+E, as a live conductor (even if you sleeve its ends) and (2) you cannot over-sleeve a G/Y single and use it for anything other than a CPC.

Kind Regards, John
 
Well I will be going back up there in just over 2 weeks to install a intruder alarm system, so will sort the Cylinder stat out then when I have some 4 core flex. It's only about 3 metres from the cylinder stat to the main junction box in the loft.
 
JohnW2 said:
..... an over-sleeved G/Y would not, in itself, be non-compliant. .... There are only two things that, per regs, you can't do - (1) use the bare CPC of, say, T+E, as a live conductor (even if you sleeve its ends) and (2) you cannot over-sleeve a G/Y single and use it for anything other than a CPC.
Click to expand...
I've just noticed that there is one thing I forgot to add, maybe because I thought it was too 'obvious' ....

Although it is compliant with regulations to over-sleeve a G/Y-insulated core in a multi-core cable in order to use it as a live conductor, I (and, I imagine, most others) would regard it as a highly undesirable practice. I am not saying that I have never done it, but that doesn't alter the fact that I regard it as a highly undesirable practice!

Kind Regards, John
 
I would regard it as a contravention unless there was no reasonable alternative.
 
ban-all-sheds said:
I would regard it as a contravention unless there was no reasonable alternative.
Click to expand...
A contravention of what? As I've said, there is seemingly nothing in BS7671 which forbids it.

It is very hard to believe that it was an 'oversight' (not to forbid it), since they have explicitly prohibited so doing with a G/Y singles, but not for G/Y-insulated cores of multi-core cables.

Kind Regards, John
 
JohnW2 said:
A contravention of what? As I've said, there is seemingly nothing in BS7671 which forbids it.
Kind Regards, John
Click to expand...

I think it was forbidden when I did my 16th, I'd be surprised if it's being allowed now.

Around the same time I worked on a replacement boiler, there was an existing water flow switch which used the green as a SL. The 'other sparks' on the job earthed the green "because the regs don't allow it" and blew up the flow switch and boiler control board.
 
SUNRAY said:
I think it was forbidden when I did my 16th, I'd be surprised if it's being allowed now. Around the same time I worked on a replacement boiler, there was an existing water flow switch which used the green as a SL. The 'other sparks' on the job earthed the green "because the regs don't allow it" and blew up the flow switch and boiler control board.
Click to expand...
It's such an iffy practice that one could well understand it being forbidden by regs now, or at any time in the past.

However, as I've said, the current BS7671 does not seem to. In general, it allows any conductor to be used for any purpose, provided it is 'identified' accordingly, with over-sleeving at just the terminations being an acceptable method of identification. The only specific and explicit exception to that general rule is that a G/Y single cannot be used as anything other than a protective conductor (earthing, bonding or CPC).

... unless, that is, someone has found something which I haven't!

Some may attempt to invoke a 'catch all' reg, by saying that it was not an acceptable level of 'workmanship', but I really don't think that can be done when, as above, the practice seems to be permitted by the regulations specifically about conductors (their use and identification).

Kind Regards, John
 
SUNRAY said:
Around the same time I worked on a replacement boiler, there was an existing water flow switch which used the green as a SL. The 'other sparks' on the job earthed the green "because the regs don't allow it" and blew up the flow switch and boiler control board.
Click to expand...
That was, of course, even more stupid than using the green as a SL :-)

Kind Regards, John
 
JohnW2 said:
A contravention of what?
Click to expand...
134.1.1

Please note I did say "unless there was no reasonable alternative". If there was a reasonable alternative, such as using a 4-core flex, but you just CBA to do that, I would have no hesitation in saying that using 3-core because you CBA was neither good workmanship nor the use of proper materials.
 
JohnW2 said:
Some may attempt to invoke a 'catch all' reg, by saying that it was not an acceptable level of 'workmanship', but I really don't think that can be done when, as above, the practice seems to be permitted by the regulations specifically about conductors (their use and identification).
Click to expand...
So despite all that people say about its undesirability, and how, ideally, it ought to be explicitly prohibited, you really think that doing it, no matter how gratuitously, is good workmanship?

Just how undesirable/inadvisable/unwelcome/confusing/generally disapproved of does something not explicitly forbidden have to be for you to say that it does not count as "good workmanship"?

WOE is the point of 134.1.1 if all that is needed to comply is not contravening any other regulation? Not contravening regulations is taken as read, so 134.1.1 has to mean more than just simple technical compliance.
 
ban-all-sheds said:
WOE is the point of 134.1.1 if all that is needed to comply is not contravening any other regulation? Not contravening regulations is taken as read, so 134.1.1 has to mean more than just simple technical compliance.
Click to expand...
But we are talking about a simple technical issue (as to whether or not it is acceptable to use a G/Y-insulated conductor as a live conductor) not a more general question about 'quality of workmanship'.

514.4.2 includes the statement:
Single-core cables that are coloured green-and-yellow throughout their length shall only be used as a protective conductor and shall not be overmarked at their terminations ....
Click to expand...
Since it would have been so easy for them to write "Conductors that are coloured green-and-yellow ...." (rather than "Single-core cables that are coloured green-and-yellow"), one has to conclude that they felt that this requirement/'prohibition' was only necessary in relation to single-core cables, and that the practice in question was therefore acceptable for G/Y cores of multi-core cables. If that reg is indicating that the practice is acceptable, then I don't see how one can say that someone who has done that it is guilty of 'poor workmanship' simply because he has done it.

... or do you feel (seemingly uncharacteristically) that you, I, or anyone else can say that something in non-compliant with BS7671, by virtue of 134.1.1, because we do not agree with what some other, explicit, regulation "actually says"?

Kind Regards, John
 
JohnW2 said:
If that reg is indicating that the practice is acceptable, then I don't see how one can say that someone who has done that it is guilty of 'poor workmanship' simply because he has done it.
Click to expand...
Does that mean that as far as you are concerned 134.1.1 is superfluous, because nothing which does not explicitly contravene any regulation can be said to be of poor workmanship?

I clearly have higher standards of workmanship than you. And so does everybody else who laments the use of an oversleeved G/Y in a multicore flex for something other than a cpc. None of us are suggesting that it is forbidden, but we are saying it is lamentable, some of us are saying that ideally it ought to be forbidden - basically none of us think it is a good thing to do. Allowed it may be. Good it is not.

So when you factor in "reasonable alternative", when you factor in it being done when the installer could easily have not done it but did it because he simply CBA to not do it then no, it absolutely was not "good workmanship".
 
Status
Not open for further replies.
Back
Top