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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?
  • Former Community Member
    0 Former Community Member

    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?




    Hi Stewart, 


    I recently had a Smart Meter fitting by SSE. Before the engineer came out I had had no problems with the electrics in the house (for many years). After installing the electrical Smart meter the RCD on the fuse box was tripping every 10 minutes. The engineer deemed there to be a problem with the electrics in the house and advised me to phone a sparky. After googling and find this forum I decided that the best option was to make my own Faraday cage around the Fuse Box so that the Radio interference would not trip the RCD. I covered the Fuse box in Aluminium Foil and to this day I have had no problems at all. 


    I will be disclosing my findings to SSE and asking they remove the smart meter for fit it away from the RCD. Not so Smart meter after all. 



    Jack8af372ff84c949c7147cb2fbc7de3515-huge-faraday-cage.jpg

     

  • 0
    I'm not sure what to say to that picture.  ?

    I suspect that many folk would not like to see that during  an inspection. What have you earthed it to ?

    I presume the consumer unit is plastic and you can rip the tin foil  cover off to get to the main switch if you need to. Be really careful where the foil goes - if any tears off and drops in the box it could be 'fun' in a bang sort of way.


    Would you be able to reveal the make and model of the RCD that trips, and the make and model of the smart meter?


    I have been saying for years that the test levels for immunity for CE marking are not really high enough, and equally the test levels for spurious emissions are really a bit too high, as the two together only work if you assume you are free to move things apart in your own home to achieve co-existance - in a case like this clearly you cannot get victim and source far enough away from each other.

    There may be other factors such as conducted interference, so mitigations with ferrite rings may help, but it is far from clear cut.

  • Former Community Member
    0 Former Community Member
    When is tinfoil an extraneous conductive part?! ?


    When I read ‘faraday cage’ I imagined something like this, which I guess could be earthed: 
    https://m.ebay.co.uk/itm/Faraday-Cage-for-Wi-Fi-Routers-Reduces-RF-Radiation-by-90-Performs-as-normal-/254436727936
  • 0
    To be honest that is even sillier, as there the thing that has to radiate for its correct operation is being screened.

    There is power control in the Wi Fi spec, so it will jack the transmit power up to compensate for the loss of signal path as much as it can but of course the ultimate range will be compromised.

    Aluminium foil is a hard material to use for screening, as it is difficult to get a continuous seam contact ,and in the end you may well have lots of accidental long thin apertures.

    At 2Ghz or so a wavelength is  ~ 6 inches (150mm) and to avoid ingress contact points at any seam should be no more than a tenth of a wave apart , ( 15mm) ideally closer.

    Nicer materials can be welded or soldered along the seams, or closed with fine spaced finger stock.

    Tin cans solder up especially well, and can provide  >120dB of shielding ( better than 1 million to 1 ratio of the fields inside versus outside) when sealed up correctly. Of course as soon as you make a hole in it to get wires in or out you have lost most of that.



  • Former Community Member
    0 Former Community Member
    Hi, 


    I've attached a picture of the Smart meter and the Fuse box as requested. Sure enough once I had removed the foil later that day it had tripped. 


    I am planning on getting an electrician to come move the fuse box, but for now its working well. 


    Thanks,

    Jack
    attachments.zip
  • 0

    The EMC requirements for RCDs have become more onerous over time. Whilst an RCD say 10 years old might be expected to deal with frequencies of 2.4 GHz, say, that wasn't necessarily the case 20 years ago.

    However, installation of an RCD close to [almost adjacent to] a source of disturbances without mitigation (metallic enclosure) would not necessarily comply with BS 7671 requirements for EMC. Whilst the use of metal consumer units helps avoid problems for electronic components in the consumer unit, it can also adversely affect the wireless signal of the smart meter, as can all of the copper within the consumer unit anyway.

    To be honest, not well thought-through at all if the wireless adaptor is too close to the consumer unit or concentrations of wiring. Separation distance of at least 100 mm are recommended.

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