NICEIC snags and solutions book

[ericmark]

Ah but if that's what's written then we can follow with impunity.

Not quite, the BS7671 can be used in a court of law, but it's not law, and we have seen how cases have not been the expected result, the Emma Shaw case I would have expected the semi-skilled worker to be found guilty but it was the foreman who carried the can.

So what happens 5 years after it is installed when the occupier replaces the unit for one requiring an earth and puts the green/yellow cable to earth? If as a result there is a death, and unless there is a death unlikely to go to court, do you really think the court will say the electrician who connected the earth wire to live was not doing anything wrong?

The book stipulates singles, but is that going to stand up in court? In the main courts seem to side with the occupier not the tradesman, and I would not like to take the chance.

 

[JohnW2]

Not quite, the BS7671 can be used in a court of law, but it's not law, and we have seen how cases have not been the expected result, the Emma Shaw case I would have expected the semi-skilled worker to be found guilty but it was the foreman who carried the can.

Courts, particularly juries, can indeed be unpredictable (and not necessarily always rational) - but I don't think that means that a court could 'get away' with claiming that something done in full compliance with BS7671 was ''wrong".

So what happens 5 years after it is installed when the occupier replaces the unit for one requiring an earth and puts the green/yellow cable to earth? If as a result there is a death, and unless there is a death unlikely to go to court, do you really think the court will say the electrician who connected the earth wire to live was not doing anything wrong?

Definitely - provided only that (as permitted by BS7671) the conductor consisted of a brown or red over-sleeved G/Y conductor in a multi-core cable. I cannot see how a court could claim something was "wrong" if it was compliant with BS7671.

In the situation you describe, one would hope that, if a death had resulted, a court would prosecute and successfully convict the person who subsequently connected that over-sleeved conductor to the exposed-c-p of a Class I item - since that person would certainly be guilty of not having complied with Part P, and possibly also guilty of manslaughter.

If the G/Y had not been over-sleeved (as required by BS7671), then that would be very different - in which case the original perpetrator, if not also the subsequent one, would presumably be 'guilty'.

Kind Regards, John

 

[ericmark]

We all know the blue when used as line in a ceiling rose should be over sleeved, and we have seen many times where the sleeve has fell off, we know in industry we use pin crimps to retain the number sleeves, so it is not an unknown problem, so if when investigated the green/yellow is not sleeved at the fan, then it is impossible to tell if the electrician installing it ever fitted the sleeves, where the whole length of exposed green/yellow colour is over sleeved then it is unlikely with shrink sleeving that any one will make an error in the future, shrink sleeve is unlikely to fall off once shrunk on, and also any future user will not even see the original green/yellow marking, but the example shows a very short length of over sleeving with the majority of the cable showing original colour. The sleeving could be simply to cover a nick in cable where it was damaged when stripping.

The problem is the courts seem loathed to blame the occupant, when either that occupant or his family has been killed, they want to blame some tradesman who should have known better, not a ordinary person.

514.4.2 Protective conductor
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 permitted by Regulation 514.4.3.
In this combination one of the colours shall cover at least 30 % and at most 70 % of the surface being coloured, while the other colour shall cover the remainder of the surface.
A bare conductor or busbar used as a protective conductor shall be identified. where necessary, by equal green-and yellow stripes, each not less than 15 mm and not more than 100 mm wide, close together, either throughout the length of the conductor or in each compartment and unit and at each accessible position. If adhesive tape is used, it shall be bi-coloured.

What you need to do is consider the full stop. So how do you read "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."? I see this as an addition to the first statement and it allows the over sleeving of the single core cable when part of a PEN conductor, it does not say if not a single core cable you can over sleeve. Specially as it continues to stipulate how much needs over sleeving, the second statement refers to 514.4.3.

As said before it is down to the English student to interpret what it says, but I would say "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." is quite explicate, and what follows it clearly refers to PEN conductors and does not distract from the first statement.

Maybe BS7671:2018 has different wording?

 

[JohnW2]

We all know the blue when used as line in a ceiling rose should be over sleeved, and we have seen many times where the sleeve has fell off, .... so it is not an unknown problem, so if when investigated the green/yellow is not sleeved at the fan, then it is impossible to tell if the electrician installing it ever fitted the sleeves...

True, and that's why it is not a very desirable practice, even if compliant with BS7671....

... shrink sleeve is unlikely to fall off once shrunk on, and also any future user will not even see the original green/yellow marking, but the example shows a very short length of over sleeving with the majority of the cable showing original colour.

Again, indeed. On the rare occasions I've done this, I have used significant lengths of heat-shrink for the over-sleeving, for this very reason.

The problem is the courts seem loathed to blame the occupant, when either that occupant or his family has been killed, they want to blame some tradesman who should have known better, not a ordinary person.

Probably - but, as I said before, if the G/Y had been over-sleeved by the tradesman, in compliance with BS7671, it's hard to see how a court could 'blame' them. If the sleeving had subsequently 'fallen off', that must have been due to actions of someone other than the person who put it on.

However, you now seem to be questioning whether over-sleeving a G/Y conductor in a multi-core cable actually is BS7671-compliant ...

What you need to do is consider the full stop. So how do you read "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."? I see this as an addition to the first statement and it allows the over sleeving of the single core cable when part of a PEN conductor, it does not say if not a single core cable you can over sleeve. ... Maybe BS7671:2018 has different wording?

The wording of BS7671:2018 is essentially the same:

514.4.2 Protective conductor
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. In this combination one of the colours shall cover at least 30 % and at most 70 % of the surface being coloured, while the other colour shall cover the remainder of the surface.
Single-core cables identified by green-and-yellow throughout their length shall only be used as a protective conductor
and shall not be overmarked at their terminations, except as permitted by Regulation 514.4.3

I don't think many people would agree with your interpretation. As for the first sentence, one needs to remember that 514.3.2 allows conductors to be 'identified' by the insulation colour OR by 'overmarking' at the terminations. A G/Y-insulated conductor with brown (or red) over-sleeving is therefore 'identified' as a line conductor. Perhaps more to the point, if your interpretation were correct (i.e. saying that a G/Y conductor must never be over-sleeved), then the sentence about single-core cables would surely be unnecessary - by including it, they are surely indicating/implying that 'overmarking' of a G/Y is permitted for conductors which are not single-core?

As said before it is down to the English student to interpret what it says, but I would say "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." is quite explicate, and what follows it clearly refers to PEN conductors and does not distract from the first statement.

It is only the very last clause of that sentence (indicating one exception to what the rest of the sentence says) that relates to PEN conductors. The main part of the sentence says "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

I may be wrong but, as I have said, I believe that you are somewhat out-on-a-limb in your interpretation of this regulation. That doesn't mean that I regard over-sleeving of G/Ys (in multi-core cables) as remotely desirable, but that's not what we're talking about - we are discussing what is, and is not, BS7671-compliant (and which hence could be used by a hypothetical court to decide whether or not something which had been done was "wrong").

Kind Regards, John

 

[ericmark]

If I was doing an EICR where the multi-core earth wire was over sleeved supplying a non fixed appliance then I would have to pass it, however much I don't like the practice. As long as neither the cable or the appliance is fixed to the building. As for example the wire from ceiling rose to bulb holder.

However if either the cable or the appliance is fixed to the building, I would expect an earth to be available even if not required due to being a class II appliance. I know in 1966 the rules changed and an earth needs taking to every ceiling rose, even if there is no earth required from ceiling rose to bulb holder.

However I have as yet been unable to find where it says an earth must be run to every fixture. I seem to remember reading where the earth must follow the same route, but I simply can't find it, so if there were two three core cables feeding the fan, and one of the earth wires were over sleeved then OK may not like it, but would have to accept it, but I am sure since the fan is fixed, if there is no earth available then it fails, but can't find where it says that.

 

[ericmark]

Found it.

543.6.1 Where over current protective devices are used for fault protection, the protective conductor shall be incorporated in the same wiring system as the live conductors or in their immediate proximity.
411.3.1.1 Protective earthing
----
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.

So no as show that would fail as there is no CPC.

 

[JohnW2]

If I was doing an EICR where the multi-core earth wire was over sleeved supplying a non fixed appliance then I would have to pass it, however much I don't like the practice. As long as neither the cable or the appliance is fixed to the building. As for example the wire from ceiling rose to bulb holder.

Fair enough but I somewhat struggle to think of any situation. let alone the one you quote, where three live cores would be needed for a "non fixed appliance" - what did you have in mind?

However if either the cable or the appliance is fixed to the building, I would expect an earth to be available even if not required due to being a class II appliance. I know in 1966 the rules changed and an earth needs taking to every ceiling rose, even if there is no earth required from ceiling rose to bulb holder. ....

Found it. So no as show that would fail as there is no CPC.

Yes, that was fully discussed earlier in the thread. We are all agreed that, strictly speaking (i.e. compliant with BS7671) over-sleeving a G/Y conductor supplying a 'fixed' item is only permitted if there is some other CPC going to the same place. However, that will not be uncommon in terms of CH wiring, which is one of the situations in which the G/Y over-sleeving is sometimes seen.

Kind Regards, John