Chris of YouTube channel CJR Electrical attended a fault where an RCD/GFCI was tripping regularly. He found that the placement of the circuits in the consumer unit (domestic distribution board) was potentially resulting in a lot of current through the RCD/GFCI and wondered if it had suffered internal damage.
Here's a link to Chris's original video where he discusses the issue:-
https://www.youtube.com/watch?v=Qr_f9kCeCdM
Tracing rogue tripping of RCD/GFCI breakers can be difficult at times, as the fault current is low and can be transient. It usually involves water heating or cooking equipment and can sometimes resolve itself when stuff dries out.
Chris replaced the RCD/GFCI with a new one designed to detect AC and pulsing DC faults associated with faulty electronic equipment, and it appears to have solved the problem.
In this video I test and then strip down the original breaker to see if it's showing signs of thermal damage. The passive tripping circuitry is very delicate and relies on a latch being maintained in position by a low level magnetic force, and being released by current being induced in a coil so it snaps open and fires the trip mechanism. The circuit board is just two inverse parallel diodes to clamp the maximum voltage from the sense coil, and some capacitors in series with the trip coil for fine tuning.
I wonder if this arrangement is prone to being affected by external vibration or magnetic fields, and how that changes with time.
Note that the current rating on these RCD/GFCI breakers is purely their rated current handling capacity. They do not have overcurrent sensing. They can only trip when detecting current imbalance through leakage.
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12 thoughts on “Was this rcd damaged by overcurrent?”
  1. Avataaar/Circle Created with python_avatars Bona minh Rasmey says:

    10 amp used in Australia for lighting 😊

  2. Avataaar/Circle Created with python_avatars Okaro says:

    The 100 A was also type A while the other was AC.

  3. Avataaar/Circle Created with python_avatars Sean Dempsey says:

    What pilchard would put 2 40amp +3 30amp and a 10am hanging of a 63 amp RCD fecking madness.

  4. Avataaar/Circle Created with python_avatars Sargent Maxis says:

    40+40+32+32+10+32= 186

  5. Avataaar/Circle Created with python_avatars Chris Solar says:

    Would be interesting to do an overload test!
    Apparently they become unbalanced and more sensitive when overloaded which would make an split load boards safer for overloads.

  6. Avataaar/Circle Created with python_avatars flow says:

    I really miss these videos, too stupid to understand the new ones with circuit board drawings and stuff.

  7. Avataaar/Circle Created with python_avatars Dirker Bornheim says:

    I am wondering whether the RCD can actually sustain even larger currents than 63A when not switched, but just the switching of the higher rates is an actual problem for the contacts (so for example the extinguish capability of the resulting electrical arc)

  8. Avataaar/Circle Created with python_avatars Alex Attis says:

    In my house (I live in the US), The kitchen has 2 sets of 20A sockets, and the microwave oven has its own 20A circuit breaker. Much different from what you would find in a British house. I am guessing the reason why the microwave has its own circuit is because it draws 13A and you would risk overloading the other circuits if you had something like a 1400w kettle plugged in which in the US, draws around 12A on 120V.

  9. Avataaar/Circle Created with python_avatars Zara says:

    He's got some deep rooted anger issues

  10. Avataaar/Circle Created with python_avatars Rhodexa's Arts says:

    that's a cool tester i didn't know existed neither i think i need it but i sure want it

  11. Avataaar/Circle Created with python_avatars carlu bambi says:

    not allowed to use those breakers and panels in Canada .Only allowed in communication and medical equipment that is considered as factory OEM equipment .We remove all those breakers and put in purpose rated fuses and fuse holders .Usually Mersen UCC .Some European stuff come with Webber or Seimens,Schneider .Most without the proper Rupture capacity and they don't have the CSA UL/ULC ratings .

  12. Avataaar/Circle Created with python_avatars Aurelius R says:

    What you said at the beginning confused me. If the RCDs are rated for 63A, they must be able to break that much fault current, right? What if it has close to its rated load running through it when a leakage to earth happens? It would still trip, and would have to break that current, right? I don't understand why you were saying it's just an isolator.

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