Yes, but I am sure it is "liable to introduce a potential" and not "liable to become extraneous".
I'm not sure what, in that context, you mean by "extraneous" - are you using it as shorthand for "extraneous-c-p"? "Extraneous", alone, is not defined in the regs. What
is defined is "extraneous-conductive-part" and, as you know, that is defined as something which is "liable to introduce a potential". So, as far as the regs are concerned, "liable to introduce a potential" and "extraneous-c-p" are the same thing ... so I don't really understand your comment above.
However, as above, if it is 'liable to introduce a potential', that does not necessarily mean that it always will introduce a potential.
Isn't that what I said? It was you who said that parts which are (deemed) NOT extraneous may be at a later date.
You still do not seem to have grasped my understanding of the significance of the words "liable to". To me (just as with the road which is "liable to" subsidence) "liable to" refers to the existence of a possibility of something which may happen in the future. Hence, if my judgement is that the conductor may (e.g. because of its routing) 'introduce a potential in the future' then I believe that it
already is an extraneous-c-p, per reg definitions (because of that '
liability to introduce a potential'), even though, at the time you see it, the resistance/impedance to earth might be extremely high. .
Doesn't the fact that it is in the ground render it extraneous without testing? ... I would not consider that a judgement call; it would be obvious.
That is
exactly my (one and only) point, whether you call it 'obvious' or a 'judgement call'. My concern is that people reading what you often write (about 'testing') could easily take you to be saying that if they measured a resistance of >23,000Ω to earth, it would not count as an extraneous-c-p even if it was emerging from the ground.
As I said, <23,000Ω (or whatever) is meaningful (definitely indicates an extraneous-c-p), but >23,000Ω means that one has to look at the situation to see whether, despite the high measurement (it could even be countless MΩ on a particularly good/bad day), it is "obviously" (or, at least, probably/ potentially) an extraneous-c-p. One clearly
cannot take a hight resistance to earth (at the time of measurement) to indicate that something is not an extraneous-c-p - as you've said it might 'obviously' be an extraneous-c-p, no matter how high the measured resistance to earth on a particular occasion.
I still don't understand the point you are making.
Does the above help at all? As I've said, I think we agree about the actual issues, my point being that what you often write about 'testing' is possibly at risk of being misinterpreted by those who do not already understand.
Kind Regards, John