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Tripping RCD after smart meter install

Stewart Mason
I got called to a property today. The RCD had started tripping after a smart meter was installed. The insulation resistance between line and cpc was over 300 Mohm on all circuits. The RCD was an MEM unit in a memera 2000 consumer unit.


Whilst at the property the RCD did not trip. I did a google search and one result suggested the RF from the smart meters transceiver was upsetting the RCD. When the smart meter was first energised I guess it starts communicating with the supplier causing said RF.


We have had 3 properties now all with MEM RCD's which have started tripping after smart meters have been installed, normally in the early hours of the day.


Just wondering if anyone else has experienced of this issue?
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  • 0

    some modern RCBOs have a small amount of always on electronics in them




    It is now probably more correct to say that most RCDS and all compact RCBOs have electronics in them - by amplifying the signal from the current transformer part, the core of the pick up can be made smaller, and by firing with an SCR or a triac across the supply into a small tripping coil, far more firing energy is available, and this means a smaller, less finely balanced  mechanism and a smaller high current  similar tripping coil to the coil for an MCB can be made. Especially for 3 phase devices where multiple contacts have to be operated, this boost in available kick is a significant advantage.


    The downside is two part.; the electronics can be damaged by transient over-voltages L-N,  and of course it does not operate if the supply voltage falls too low. Equally it is less likely to suffer a mechanical fault, as the mechanics are simpler.

    And  it seems some  may be misfired if the electronics  inside is poorly designed in terms of RF rejection.

    There is a good description of the innards of a modern RCBO
    video, as linked to in another thread earlier in the year.

    T


Reply
  • 0

    some modern RCBOs have a small amount of always on electronics in them




    It is now probably more correct to say that most RCDS and all compact RCBOs have electronics in them - by amplifying the signal from the current transformer part, the core of the pick up can be made smaller, and by firing with an SCR or a triac across the supply into a small tripping coil, far more firing energy is available, and this means a smaller, less finely balanced  mechanism and a smaller high current  similar tripping coil to the coil for an MCB can be made. Especially for 3 phase devices where multiple contacts have to be operated, this boost in available kick is a significant advantage.


    The downside is two part.; the electronics can be damaged by transient over-voltages L-N,  and of course it does not operate if the supply voltage falls too low. Equally it is less likely to suffer a mechanical fault, as the mechanics are simpler.

    And  it seems some  may be misfired if the electronics  inside is poorly designed in terms of RF rejection.

    There is a good description of the innards of a modern RCBO
    video, as linked to in another thread earlier in the year.

    T


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