Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • Replies 100 replies
  • Subscribers 45 subscribers
  • Views 1929 views
  • Users 0 members are here
Options
You may also be interested in

My war against dual rcd boards

Newfutile
As each (RCD) Residual Current Device must not have more than 30% leakage current on it.
It's hard to see how dual (RCD) Residual Current Device boards can be fitted at all these days.
i come across so many dual rcd boards with solar, evse and heat pumps on them, these have all been recently installed.
i wonder if BS7671 should state: Dual (RCD) Residual Current Device boards shall not be fitted, unless it can be shown (and documented) that they are suitable for the combined leakage currents expected .
otherwise developers will keep specifying them and i will have keep educating them on the many reasons a type A rcd should not be shared with other equipment!.
maybe manuafactuers instructions should also state : not suitable for a shared rcd, for certain equipment.
Parents

  • If you were to do a Type A RCD test on the RCDs installed in the consumer unit, what test current does the installation tester deliver?

  • in reply to Sparkingchip
    Sparkingchip said:
    If you were to do a Type A RCD test on the RCDs installed in the consumer unit, what test current does the installation tester deliver?

    Would that not depend on whether you were '. . . doing a Type A RCD test' or '. . . testing a Type A RCD in accordance with BS 7671 (643.7.1) and/or (643.8)' ?

    In the former case it would be an AC waveform with superimposed pulsed DC whilst in the latter case it would be an AC waveform.

     - Ross

  • in reply to Ross C

    As in the photo, what amperage is the pulsed DC current test current that the tester will deliver for a X1 30 mA Type A RCD test?

  • in reply to Sparkingchip

    A multiplier of 1.4 comes to mind, so with the instrument set as in the photo (30 mA × 1 × 1.4) = 42 mA ?

    - Ross

  • in reply to Ross C

    1.414 the square root of 2, so 42.42 mA.

  • in reply to Sparkingchip

    I thought that A type RCDs only needed to cope with 6mA of d.c.?

       - Andy.

  • in reply to Ross C

    Hang on. BS 7671 643.8 specifies, "alternating current test at rated residual operating current (IΔn)". No more, no less.

    ETA: your instrument's calibration certificate will show the actual current which it delivers.

Reply
  • in reply to Ross C

    Hang on. BS 7671 643.8 specifies, "alternating current test at rated residual operating current (IΔn)". No more, no less.

    ETA: your instrument's calibration certificate will show the actual current which it delivers.

Children

Community Rules & Guidelines