they were, they were subject to routine NDT.
Help with crimping
- Thread starter pjo123
- Start date
they were, they were subject to routine NDT.
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You really ought to be a politician or barrister (maybe you are!), since you are majoring on extracting a 'short answer' ("No") out of Bernard and myself without taking into account the associated 'long answer' - a typical Perry Mason tactic
As I keep saying, and have attempted to illustrate with some figures, the fact that neither Bernard nor I, or even you, have never seen a crimp fail in a domestic setting does not go anywhere near far enough to prove that they are so much more reliable than screwed joints that they do not need to be accessible for inspection. Based on those observational facts alone, crimps could be much less reliable/safe than screwed connections, and we wouldn't be any the wiser.
How many people do you think have actually seen some of the catastrophic failures that could occur in an aircraft, and which incredible amounts of time, effort and money goes into trying to prevent?
Kind Regards, John
I'm very pleased to hear that, but not surprised - so what was your point?
Kind Regards, John.
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lol, i prefer miss marple myself. Sometimes a short answer to a simple question is all thats needed. I'd just like it if Bernard would stop maneuvering around the obvious yes or no response i was looking for.You really ought to be a politician or barrister (maybe you are!), since you are majoring on extracting a 'short answer' ("No") out of Bernard and myself without taking into account the associated 'long answer' - a typical Perry Mason tactic
13? Am i warm? Can i have another total guess based on zero experience?
I just looked at crimpers in a professional tool catalogue. The price range was from £11-odd to £473! The good ones seem to start around £50, and are similar to the AMP one I was describing. The more expensive ones specifically state that they are designed for use with the same manufacturer's terminals only. That's another possible source of bad joints - a good professional tool used with cheapo Screwfix terminals. (other cheapo brands are available)
John, there are many instances of safety-critical welds that are not accessible for inspection - under the North Sea for example. This is why there are Coded Welders, whose skill levels are such that their work is dependable.
John, there are many instances of safety-critical welds that are not accessible for inspection - under the North Sea for example. This is why there are Coded Welders, whose skill levels are such that their work is dependable.
Point being that Bernard just 'feels' that a crimp needs to be accessed since he 'feels' (albeit without any experience) that they have a 'significant' chance of failure (which has not been supported with any data, whether anecdotal other otherwise)
Bernard 'feels' that a cold welded joint does not need to be accessed as he 'feels' that they are many more times more reliable.
I think that if he has no experience of a failed crimp and also no experience of a failed weld, then why does he draw the conclusion that one should be different to the other in regards to accessibility for inspection.
Yes, but to continue the analogy, you already know the short answer but, like Perry Mason (or Miss Marple, albeit not a lawyer!), your only motive for repeatedly asking is that you are trying to get him to say it in front of 'the jury' (and then, if you are Perry, attempt to stop him qualifying the short answer)!
Maybe I'm losing the ability to communicate clearly, because you seem to be missing my point. The very limited experience of Bernard and myself, which you keep returning to, is not the issue. I fully accept that if one asked all the practising electricians here (with a lot of combined experience between them) how many failed crimped joints they'd seen in domestic environments, the answer would very likely be zero (or close to zero). I'm not going to repeat the arguments, but I don't believe that is anything lile enough evidence to indicate that crimped joints are so much safer than screwed joints that it's OK for them to not be accessible for inspection.
As for your '13', that's almost certainly not very warm at all, since the answer in many cases is going to be zero! The fact that a particular possible failure has not yet been seen, or is seen only very rarely, does not mean that it's something one doesn't have to think about when doing risk assessments, and formulating plans (or rules/regulations) designed to minimise the potential risk.
Kind Regards, John.
Indeed, the three I have range from £11 to about £70, but I have looked at more expensive ones.
I can't say that I've seen £473 ones, but I can but repeat that I haven't personally yet seen any which appear to correspond with what you've described. There is virtually no difference between my £11 and £70 ones and both look remarkably like the ones that BAS is always advocating, and which I suspect many electricians are using.
Yes, I forgot to mention that as an option. If crimped joints of electrical cables were only allowed to be made by highly specifically trained, certified and periodically re-validated personnel, then many of the concerns would go. Maybe there would also be a requirement for X-ray, ultrasound or whatever checking of each crimped joint, too, just as I imagine is usually the case for safety-critical welds!! ... and, anyway, don't they have divers inspecting the undersea structures all the time?
Kind Regards, John
Well, as you know, I have similar feelings, but maybe have slightly different ideas about the implications. My view is that, given that most joints are required to be accessible for inspection, then no type of joint should be allowed to be inaccessible unless there is very strong evidence that it is very much 'safer'/less prone to failure than the others.
You are basing your view not really on data/evidence, but rather the absence of it. I have existed in and around safety-critical, data-obsessed and evidence-obsessed environments for most of my life, in which your approach would be unthinkable. Any theoretical risk should be assumed to be present in practice unless/until proved absent.
Kind Regards, John.
If your contention were to be correct, what would be the problem with my perceived Mason Perry approach? Wasn't he a good guy?
No, you communicate clearly, but if i were to be critical, you could try to be a little more concise
I agree that just asking people here will not give un-deniable proof either way, but they are permitted by the regs and presumably have undergone some testing by a collection of white coated bods in some way connected to the IET. The regs even go a little further by conditioning the crimp types that can and cannot be used on different cable types. I think it says something like 'can be used on all cable types unless marked with.......(from memory as my book is on the job at the mo, maybe someone can fill in the blanks here)
Indeed, that is true. As you may know Leicester city council has recently been forced to admit under the freedom of information act that they have not made provision in their emergency action plan for being overrun by a zombie invasion. Careless fools!
In terms of 13 not being warm, then zero is positively chilly. Have you seen anything like air crash investigators on some Natgeo? There are teams specifically tasked with looking at reasons for catastrophic failure. So ill revise my total guess to 297.
Maybe such evidence exists? Maybe the IET considered this evidence prior to publishing their views on the application of crimps? MAybe you could ask someone over at the IET about this subject?
Incorrect. What view do you think i have expressed?
Are you not doing just that yourself?
You don't hold exclusivity in that respect
. However, that fact that you use the word 'obsessed' twice in that context does seem to speak volumes.
What approach do you (mistakenly) think I have adopted?
Thats just plain old silly talk, which i shall disregard as a potential 'senior moment'. Please refer to previous Leicester/Zombies comment.
1196?
I'm certainly not known for my brevity. However, that's not because I can't be concise - it's because if I am concise, then some annoying person invariably picks me up on some detail or caveat and I could have included, but omitted in the interests of brevity!!
What regs are you talking about? The real problem underlying this whole issue is that BS7671 says virtually nothing - simply a few words in one place about a joint made with a "suitable (or is it 'appropriate') compression tool". If it was a bit more specific about what was acceptable, then maybe a lot of this discussion would be unnecessary.
Yes, I've seen many of those programmes, and I actually know a couple of air crash investigators, but I don't get your point. Crashes and crash investigators only come into the picture when the risk-assessment and risk-prevention measures have failed. Maybe you misunderstood or misread the question I asked (to which you have given answers of 13 and 297In terms of 13 not being warm, then zero is positively chilly. Have you seen anything like air crash investigators on some Natgeo? There are teams specifically tasked with looking at reasons for catastrophic failure. So ill revise my total guess to 297.
) For a start, it was essentially a rhetorical question, but what it was asking (or trying to ask) is how many people have seen most of the theoretically possible failures which are considered and addressed by design and/or regulations as part of the risk-minimising design/regulation processes. The vast majority of those 'theoretical possible failures' are things which have never happened in the past (hence answer=zero) and will hopefully never happen in the future - but in many cases that is precisely because the possibility was considered and steps taken to minimise the risk of their occurring. I'm sure you really understand all this - it's at the basis of risk assessment, risk management and risk minimisation, in very many fields.Kind Regards, John.
erm, are we writing and posting simultaneously?
This could get a tad complex, good job its very nearly beer o'clock
This could get a tad complex, good job its very nearly beer o'clock
You're right. I expressed myself badly. As you say, I am basing my view on the absence of data/evidence of which I am aware.
What I should have said is that when there is an absence of data/evidence in relation to a matter of safety, then one should adopt a conservative/pessimistic view ('assume the worst') and only dismiss a theoretical risk if there is positive evidence (rather than the lack of negative evidence) for so doing.
Kind Regards, John
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