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Discussion on Testing & Verification of an installation

2»

Comments

  • #32
    [Deleted User]
    Posts: 7,499 ✭✭✭ [Deleted User]


    gctest50 wrote: »







    One way was remove to the phone socket & its wiring and run the conduit for light switch up in a straightish line vertically like a civilised human


    The reason its diagonal at the end is because he reused an old conduit.


  • #33
    Risteard81
    Registered Users Posts: 2,567 ✭✭✭Risteard81


    2011 wrote: »
    Risteard81 wrote: »
    Verification is required during erection and on completion. So the installer certainly is in a position to inspect throughout the job.

    Agreed and never disputed.
    The point that I and others are making is that a REC is inspecting his own work which is nonsense. This is why so many rules are routinely ignored.
    I never suggested that periodic inspection could find all issues - that is why Periodic Inspection Reports are not certificates but reports. To suggest I claimed otherwise is false.

    Agreed.
    What I am suggesting is that when you stated that a house with a diagonal chase was uncertifiable is balderdash.

    The point that we are fundamentally disagreeing that you will not engage on is:
    1) Self certification is a nonsense
    2) Many installations that are not compliant with the rules are certified.
    It's not balderdash to state that it is impermissible to certify an installation with Rule breaches. I never suggested that it never happens. It shouldn't though, and people shouldn't pretend that the light switch wiring shown is acceptable.


  • #34
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,532 Mod ✭✭✭✭2011


    Risteard81 wrote: »
    It's not balderdash to state that it is impermissible to certify an installation with Rule breaches.

    Agreed, but that is not what you said.
    You specifically said it was “uncertifiable” which means it could not be certified.
    Clearly this is not the case.
    I never suggested that it never happens.

    Then we agree.
    It shouldn't though, and people shouldn't pretend that the light switch wiring shown is acceptable.

    Yes, I agree.
    My point is that although it is not correct and should not be accepted it would not concern me that much. I have seen so many serious issues issues that more minor ones like this are not as big a deal to me.

    So it would seem that our points of view are not as far apart as I thought, however I see thy you did not address my point on self certification. Judging by your posts you insist on a high standard of work with attention to detail, surly certification by a third party would be to your advantage? As you now accept that some certified installations are not compliant you must agree that some only get away with this because of self certification?


  • #35
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,532 Mod ✭✭✭✭2011


    Gashmuncher wrote: »
    It will, but not enough to be detected by electricians testers which only read to two signifigent digits i.e. down to .01 of an ohm.

    Then the resistance is not “fixed”. Depending mainly on the length of run, the change in temperature and the CSA of the cable the resistance change by more than 0.1 ohms.

    See link: https://www.cirris.com/learning-center/general-testing/special-topics/177-temperature-coefficient-of-copper
    There is no regulation which prohibits a good join on a cable.

    There are plenty if we take your position that any low resistance joint is a good joint.

    A good tester will identify a bad (high resistance) connection.

    I disagree. You are putting too much faith in what testing can achieve.
    A joint could be bad because it does not have sufficient IP rating, lacks mechanical protection, does not prevent direct contact with live parts, is susceptible to corrosion, puts undue strain on the conductors....... The list goes on.
    Can you quote the regulation which prohibits a good joint on a cable

    Yes, I think I can when I have the rules in front of me. I will come back to you later on this.
    Yes higher resistance but not desirable and it's not more complicated

    So if it simply twisted mains voltage wires together and the resistance across the join was low that would be acceptable?
    Not correct, once again there is no rule which prohibits a good joint in conductors. Any good low resistance connection is always acceptable

    As above low resistance is not the only criteria that a cable joint should be judged on.
    It has resistance, but not enough to be picked up by a test meter which only reads to two significant digits.

    That is not correct.
    Even the test leads have a resistance that standard test meters read. Besides it is not just the resistance of the joint at the time of assessing it that is important it is also how it performs over time. This is why so many other tactoyhave to be considered, see some examples above.


  • #36
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    2011 wrote: »
    As above low resistance is not the only criteria that a cable joint should be judged on.
    .

    An example would be bonding straps. The horrific practice of simply clamping the cut earths under the screws rather than using lugs. Massive difference in quality. Not much difference in test results.


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  • #37
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    2011 wrote: »
    .
    That is not correct.
    Even the test leads have a resistance that standard test meters read. Besides it is not just the resistance of the joint at the time of assessing it that is important it is also how it performs over time. This is why so many other tactoyhave to be considered, see some examples above.

    Another example similar to bad connections,

    Using the tables G muncher linked to, 1 meter of 1.5 copper is 0.02 ohms. So 1 cm of it is 0.0002 ohms.

    So if we ran in 50 meters of 10 square, and part way along the circuit we add in a link of 1.5 square 1 cm long, or pare the 10 square copper down to 1.5 to eliminate connections , it will be a serious reduction in integrity, and similar to a bad connection. But the 2 place ohm meter cant detect it

    Even paring it down to 0.5 or even 0.1 square it's still not going to show. But it is now 15 times smaller than 1.5, but it's resistance is still well below the meter resolution.


  • #38
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,532 Mod ✭✭✭✭2011


    2011 wrote: »
    As you now accept that some certified installations are not compliant you must agree that some only get away with this because of self certification?

    From the reluctance to address this question we can all draw our own conclusions.


  • #39
    Risteard81
    Registered Users Posts: 2,567 ✭✭✭Risteard81


    2011 wrote: »
    2011 wrote: »
    As you now accept that some certified installations are not compliant you must agree that some only get away with this because of self certification?

    From the reluctance to address this question we can all draw our own conclusions.
    No reluctance. I'm away for a few days. That's the only reason.

    People should only certify compliant work.


  • #40
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,532 Mod ✭✭✭✭2011


    Risteard81 wrote: »
    No reluctance.

    That does not appear to be the case as the question remains unanswered.

    It’s a simple question, you either believe that:
    A) Self certification should be replaced with third party certification.
    B) Self certification is acceptable.

    Personally I believe option A to be the correct answer as there are certified installations that do not comply with the rules as you now accept.


  • #41
    Tuco88
    Registered Users Posts: 1,052 ✭✭✭Tuco88


    If you know the resistance of 1m of 0.75mm^2 wire thats fine. Its not much good to you when you can only guess the lenght of the cable run, provided you have no connection issues, all your values will vary.

    Take a typical control loop, a knife edge terminal barely touching won't show as a bad connection.

    Depending on resistance values to prove good connections is not enough imo.


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  • #42
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Tuco88 wrote: »
    .

    Depending on resistance values to prove good connections is not enough imo.

    Thats the point I was making. The tables showing resistance values of cables was not really relevant to the fact 2 cables just touching can show low resistance which might not be measurable by a tester compared to a proper connection. A good connection has to stand the test of time.


  • #43
    gctest50
    Registered Users Posts: 9,605 ✭✭✭gctest50


    You could load the circuits up to their limits and have a snoop around with a IR camera


    Be a extra bit of happiness


  • #44
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,532 Mod ✭✭✭✭2011


    I suppose that it all starts with understanding the limitations of what testing can achieve.
    This is an area that generates a lot of confusion.


  • #45
    Risteard81
    Registered Users Posts: 2,567 ✭✭✭Risteard81


    2011 wrote: »
    Personally I believe option A to be the correct answer as there are certified installations that do not comply with the rules
    This can be dealt with through disciplinary procedures, however.

    People shouldn't think it acceptable to certify non-compliant installations. Third-party certification would be no guarantee as to what someone has done either, as defects could be hidden from view.


  • #46
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,532 Mod ✭✭✭✭2011


    Risteard81 wrote: »
    This can be dealt with through disciplinary procedures, however.

    People shouldn't think it acceptable to certify non-compliant installations. Third-party certification would be no guarantee as to what someone has done either, as defects could be hidden from view.

    A very weak argument in my opinion, but at least it’s an answer :)
    Obviously some deviations from the rules can be concealed, but many of the most dangerous ones can’t. I don’t know about you but anytime I assess myself I get an A+ :D

    My biggest issue with third party certification is the additional cost and inevitable schedule impact for the customer.


  • #47
    Risteard81
    Registered Users Posts: 2,567 ✭✭✭Risteard81


    2011 wrote: »
    A very weak argument in my opinion, but at least it’s an answer :)
    Obviously some deviations from the rules can be concealed, but many of the most dangerous ones can’t. I don’t know about you but anytime I assess myself I get an A+ :D

    My biggest issue with third party certification is the additional cost and inevitable schedule impact for the customer.

    Well, if you accept that inspection is more important than testing (with testing merely supplementing inspection), then it stands to reason that someone coming along later and simply testing things may well not find what you have done. It is not correct to suggest that dangerous defects cannot pass tests - they can.


  • #48
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Risteard81 wrote: »
    Well, if you accept that inspection is more important than testing (with testing merely supplementing inspection), then it stands to reason that someone coming along later and simply testing things may well not find what you have done. It is not correct to suggest that dangerous defects cannot pass tests - they can.
    How do you inspect an employee install, trace every circuit along its entire length?


  • #49
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,532 Mod ✭✭✭✭2011


    Risteard81 wrote: »
    it stands to reason that someone coming along later and simply testing things may well not find what you have done.

    Yet inspectors still manage to find issues when they inspect. See the top 10 rule breaches on page 3 here. I would argue that far fewer installations would certified with these breaches if only third party certification was permitted. Obviously a minority of RECs are quite happy to self certify these installations with these breaches in place. God only knows what else is out there that has not been inspected.
    It is not correct to suggest that dangerous defects cannot pass tests - they can.

    It is also not correct to suggest that I suggested that :)

    There is no perfect solution, but that does not mean that the situation can not be improved.


  • #50
    Risteard81
    Registered Users Posts: 2,567 ✭✭✭Risteard81


    Bruthal wrote: »
    Risteard81 wrote: »
    Well, if you accept that inspection is more important than testing (with testing merely supplementing inspection), then it stands to reason that someone coming along later and simply testing things may well not find what you have done. It is not correct to suggest that dangerous defects cannot pass tests - they can.
    How do you inspect an employee install, trace every circuit along its entire length?
    You supervise it obviously.


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