Ring Main at Consumer unit

I thought that the coding I suggested would raise a few comments, but those wanting a C2 need to tell us why. The Tails do not lack fault protection Andy, the sheath has nothing to do with that. If you think that a short length of primary insulation exposed could reasonably be mechanically damaged, please explain that too. "A lunatic with a sharp knife" will not do, he could also cut through the sheath just as easily.  It appears to me that you are considering the sheath as extra insulation, it is not it could be equally a steel foil, which would short the tail to Earth if damaged enough but that is the purpose of mechanical protection, it makes the cable less likely to be damaged but not impossible to damage given the right conditions. The other Andy (Spark) has shown us badly stripped cables, but these will presumably inside an enclosure so might cause a fault, but not a touch danger. They simply indicate a careless bad workman and should be a C3. The one entering a Henly block is a C1, there are accessible exposed live conductor(s) showing and capable of human contact (although quite difficult, it meets IP2x but not IP4x). Stripping the sheath of a longish amount is necessary inside some CUs because the sheathed tail cannot be bent sufficiently tightly through 180 degrees to fit the main switch. An alternative is to enter at the top with an IP4x gland, but this rarely happens. Those using Stanley knives for stripping are asking for trouble, particularly with a new blade, I find proper strippers or an electrician's knife much better. Good tradesmen would cut and strip the tail again (properly) and discard the damaged end.


The only defect of an exposed insulated single conductor is, by the regulations, only a lack of mechanical protection. The insulation is in reality good for several KV at least, so cannot be described as dangerous to touch, just to mechanically damage. as such damage is unlikely, how can you give a C2, making the whole installation unsatisfactory? It simply requires some simple maintenance by small improvements. Compare it to a plug where the cord grip has failed or become loose, does this make the appliance unsatisfactory, and is it dangerous to touch. No, it may be dangerous if you pull the cord hard enough to disconnect the CPC, but with proper plug fitting that cannot happen without the live already having been broken, so not very dangerous.

but those wanting a C2 need to tell us why. The Tails do not lack fault protection Andy, the sheath has nothing to do with that.

I beg to differ. Without a sheath they don't comply with 412.2.4.1 (ii) (a) and without that it's hard to see which bit of chapter 41 the arragement can be claimed to comply with.


The regs gave up relying on basic insulation alone for shock protection at least 40 years ago - basic insulation exposed to touch is no more satisfactory than unearthed steel conduit containing 230V singles or a circuit with class I accessories but no c.p.c. - any of those would be a C2 to me.


Certainly short exposed length are likely to be a lower risk in practice than longer ones - likewise a single unearthed appliance less of a risk than an entire circuit of many such - but the EICR codes too crude to take much account of such factors.


To me - immediate danger (e.g. exposed conductors) - i.e. zero further faults needed for danger to occur - C1.


Danger if one further fault occurs - C2


Danger only if two further faults occurs would normally be acceptable (our normal double fault to danger) - but if current regs demand further protection omission of that protection would be a C3.


   - Andy.

Andy, I did not say it is compliant, just not dangerous. The basis for coding is only the level of danger, not specific regulation compliance. This is exactly the problem with many EICRs, any deviation is coded to be as high as possible, for whatever reason. C3 is "requires improvement" as I am sure you realise, this requires improvement and yet is not dangerous in any way unless damage is caused which could equally happen to any exposed sheathed wiring. The details are the degree of risk that this is likely (no) and the relative lengths for damage, this very small, other wiring probably very large. This is a subtle case of degree, and therefore I do not see it as a C2. If there were yards of singles everywhere I would have a difference of degree and therefore a C2, but in the same way with a PAT, a lamp with 2 core unsheathed flex, I would not condemn it, just suggest improvement. In case you had not noticed, there are still many of these still about, and even some being sold new, particularly twisted cotton-covered conductors, which is NOT a sheath. You may wish to differ, but it is the opinion of the Inspector which he should be prepared to justify, which I think I have in a fair and reasonable way, just as I would in Court. You may make a counterargument, but need to say WHY the risk is higher than I have suggested, preferably with a previous case where this defect in the same length was proved dangerous.

I'm tending to agree with DZ. The only trouble with a C3 is that the installation is deemed "satisfactory" and I haven't met any home owners who have asked me to fix a "requires improvement". I think we all agree that this one definitely requires improvement as although it isn't a problem right now it has the capacity to become one in the future. So, what we need is another code where it's not dangerous but needs fixing before the installation can be considered "satisfactory". Oh,'ang on . . . .

Maybe there should be cumulative coding, two or more C2s for the same item equals a C1  ?


Presumably though an unlimited number of C3s is acceptable. ?

I would still more than likely give it a C2,  there’s a reason for the outer sheath. All the guidance points to C2 if basic insulation is capable of being touched or is touching metal. In this case it sounds like the tails are passing though either a drilled hole or a knockout without protection. So there’s a remote risk of it becoming dangerous in time. If we had a photo we could all make a better judgment  perhaps it is a C3 or is there a reason it was given a C1.

I have mixed feelings about tails with colour coded sheaths the same colour as the insulation, whilst they aid identification it is far easier for less knowledge and less observant people to spot if the sheath is missing or damaged when the sheath and insulation are two different colours.


Some instrument test lead manufacturers specifically use two different colours to make it easier to spot damaged test tests.