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RCD TESTING BS7671:2018+A2:2022

sparkiemike

Anybody notice the changes to 643.7.1 and 643.8 when it comes to RCD testing. In the note it says that "Regardless of the RCD type, effectiveness is deemed to have been verified where an RCD disconnects with in the time stated below with an alternating current test rated at residual operating current I△n"

So the minimum requirement is to set your instrument to RCD type AC and carry out the test even if you have a Type A or Type B RCD.

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  • So, do electricians need a fancy tester to test Electric Vehicle Supply Equipment or can they use their Robin KTS1620 they bought over twenty years ago?

  • in reply to Sparkingchip
    Sparkingchip said:
    So, do electricians need a fancy tester to test Electric Vehicle Supply Equipment or can they use their Robin KTS1620 they bought over twenty years ago?

    If the RCD under test is part of the EVSE, then you'd need to simulate the vehicle connected to the EVSE to turn on the supply to the vehicle connector ... but if the EVSE has an RCD inside that's safe to access for testing, which doesn't need the supply relays to be turned on, or the RCD is upstream of the EVSE, then I agree.

    Why do people want to test RCDs to death, and simply rely on other protective devices? Just because fuses were both simple and "one shot", doesn't mean an mcb with a number of connected moving parts can't fail (and some indeed do) and can't be tested. Maybe we should get some high current injectors and test mcb's ?

Reply
  • in reply to Sparkingchip
    Sparkingchip said:
    So, do electricians need a fancy tester to test Electric Vehicle Supply Equipment or can they use their Robin KTS1620 they bought over twenty years ago?

    If the RCD under test is part of the EVSE, then you'd need to simulate the vehicle connected to the EVSE to turn on the supply to the vehicle connector ... but if the EVSE has an RCD inside that's safe to access for testing, which doesn't need the supply relays to be turned on, or the RCD is upstream of the EVSE, then I agree.

    Why do people want to test RCDs to death, and simply rely on other protective devices? Just because fuses were both simple and "one shot", doesn't mean an mcb with a number of connected moving parts can't fail (and some indeed do) and can't be tested. Maybe we should get some high current injectors and test mcb's ?

Children
  • in reply to gkenyon

    "Why do people want to test RCDs to death?"

    Cos they can become inoperative if not freed up occasionally. Then when they are really needed they do not disconnect the supply.

    I'd rather over test than risk a death or fire.

    TT?

    I recently attended a holiday chalet which was recently refurbished by a builder.

    • Fault 1 found. Main earthing conductor was disconnected.

    Fault 2. Reversed supply polarity at the new consumer unit.

    I always test R.C.D.s to death even when I do a small job. The chalet was to be let to the great unwashed.

    Z.

  • in reply to Zoomup
    Zoomup said:

    "Why do people want to test RCDs to death?"

    Cos they can become inoperative if not freed up occasionally. Then when they are really needed they do not disconnect the supply.

    Wouldn't pushing the test button frequently do the same thing?

    What does a tripping time test do for you?

    DO you push the test button BEFORE the tripping time test, or AFTER?

  • in reply to gkenyon

    With time delayed R.C.Ds. the tripping time test is useful to confirm correct delay time. Or if just using the test button the gentle hum for a short time before the time delayed R.C.D. trips off confirms the delay for the poor man with no tester. But the tester method is more scientific.

    Anyway it is good to show off in front of the customer with impressive test gear. It gives 'em the impression that we know what we are doing and are earning our money.

    In the real world with a real genuine fault, does the test button get pressed before the need for automatic R.C.D. operation?

    A recent test on a 30mA R.C.D. using the test button would have tripped it off. BUT the cowboy builder that installed the new consumer unit in the TT earthed holiday chalet had left the main earthing conductor disconnected. Discuss.

    Z.

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