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Tricky PAT question

TrigPoint
Hello everybody! I could use a bit of sage advice regarding PAT testing unusual items.


To give you a bit of background, I'm in a bit of a tricky spot because I just took over a role as a PAT tester and it came with two very smart testing devices which save the identification number, create a bar code and save the tests required for whatever item it is. Subsequently everyone in my company seems to think that all I have to do is type in a number and the test is automatic.


Unfortunately, the more items I test, the more I notice that the tests that have been inputted, are not anything I want to put my name/initials to. I mean, a few days ago I was prompted to complete a touch current test on a bog standard class I toaster. I've found; tests on leads that do not test for polarity, a test that checks IR at 500V and also checks leakage but nothing else, and it seems to have been standard to cobble together 4 and 5 pin plug and socket adapters for testing 35/63/125A cables using 3 pin plugs and sockets which connect to the PAT tester... d'oh! So it's taking me a lot longer to test things than my company expects. It's a bit of a nightmare if I'm honest as almost every test needs checking and most need reprogramming. 


To make the problem worse, it seems my bosses really trusted the person who was doing this before me and so every time I run into a problem or a test that doesn't work properly, sometimes in front of them, it's sort of taken as me being incompetent rather than the test being substandard in the first place. So, I can't really ask my colleagues for advice because it kind of works against me. So that's why I joined here and I'm asking you. Thank you for reading this far by the way. I'll get down to the real question now...

I test everything from museum exhibits and set for TV shows to your average kettles, toasters, microwaves and so on. But occasionally something comes up with a lot of exposed painted metal which is earthed using an earth nut. In this case it's a booth for a TV game show. How would one decide what a suitable resistance might be for such items during an earth bond test? Also what are the implications for Insulation resistance? You'd think it would fail because of the large amount of metal with no real insulation on it connected to the circuit. This has me beat! I have no idea what to do to test it properly.

If anybody out there has any advice I would really appreciate it.


Thanks


Trig  


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  • 0
    I use an old Robin PAT 5500. its programable, heavy and very yellow. It produces various currents up to 26A at 3-4V when checking the earth bond. For most appliances that have resistive elements 26A is appropriate and for mains powered IT equipment I use the earth bond test current at 100mA . The earth bond maximum resistance value can be adjusted so that long extention leads can be checked without automatically failing.

    " Insulation testing even at the 500V, (and in some models also a flash test at 3500V) is carefully current limited, designed to simply deliver an agonsing but non-lethal shock to anyone fool enough to insulation test themselves as well as the device under investigation." 


    Lol .... do people really test themselves before testing the equipment?

    Personally, I find the 5500 a very reliable, robust and accurate machine which can be tailored to cope with most types of electrical appliances


    Legh
Reply
  • 0
    I use an old Robin PAT 5500. its programable, heavy and very yellow. It produces various currents up to 26A at 3-4V when checking the earth bond. For most appliances that have resistive elements 26A is appropriate and for mains powered IT equipment I use the earth bond test current at 100mA . The earth bond maximum resistance value can be adjusted so that long extention leads can be checked without automatically failing.

    " Insulation testing even at the 500V, (and in some models also a flash test at 3500V) is carefully current limited, designed to simply deliver an agonsing but non-lethal shock to anyone fool enough to insulation test themselves as well as the device under investigation." 


    Lol .... do people really test themselves before testing the equipment?

    Personally, I find the 5500 a very reliable, robust and accurate machine which can be tailored to cope with most types of electrical appliances


    Legh
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