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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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    You would need to create an account on  the UK defence gateway to access the "Dstan"  documents officially .
    https://sts.defencegateway.mod.uk/

    For obvious reasons if you answer 'no' to the 'do you work for the MOD' questions you get a civilian access only.

    civilian sign up is type 5
    https://sts.defencegateway.mod.uk/registerStep2.aspx?regType=5

    Then certain standards are kept from you, mostly the ones about munitions, and some other hot topics that might be useful to enemies.

    However, all the basics, like EMC stuff, and the mechanical transport (shake rattle and roll...) and the environmental tests are available to everyone, free issue, or were when I last looked late last year, mainly so that when tendering for MOD contracts, companies know what standards to manufacture to.

    They don't hand out registration willy nilly, but any person or company that is potentiually part of the MOD procuremnet chain, and so needs the access so thay can make, sell or test components, would normally get in.

    There are plenty of older copies of many of the Defstan docs out on the web, but it is all crown copyright, so respect that. Note that  '511 is mostly EMC for general, thought some sections may also apply to marine.



  • 0
    I was forgetting that it was general as this was a marine project so it was the marine bits I was interested in, but the problem was that while it was part of the MoD procurement chain, some of the potential suppliers were non-UK and the answer was the standard can't be released overseas. Therefore if some suppliers will not be allowed to access the standard you can't name it in the Specification.

    Alasdair
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    Another Memera 2000 board replaced today due to the RCD tripping after a smart meter install.
  • 0
    I seem to recall Smart Meters transmit on a restricted/secure bandwidth on the 2G spectrum.
  • 0
    It looks to me that the fault applies to MEMERA2000 RCDs because they pre-date the current EMC requirements, and smart meters are built down to a price.


    I am not in the collander wearing brigade, but I have printed a notice to any potential smart meter fitters to call me FIRST, and affixed it to the current meter, and service head, along with my phone number. They will be told in no uncertain terms NOT to fit one, as they're not reliable. (I know nothing about dangers, not having investigated this, but unreliability is proven. They have electronics in, and that fails).


    Traditional electromechanical all the way baby!
  • 0
    Are the MEM RCDs voltage dependent or voltage independent?


    Andy
  • 0
    I had a similar experience a month or so ago. 20 yo Crabtree RCD was tripping randomly at night, usually on a Monday night between

    midnight and 2am in the morning. Once reset, no trips for another week. I changed the RCD, it still happened.

    Eventually I changed the board for a metal clad RCBO board. No trips since. All testing was done beforehand, no fault anywhere.

    https://communities.theiet.org/discussions/viewtopic/1037/23887
  • 0
    The smart meters use two communication systems to send their data back and the system chosen depends on where you are in the country.  Some use the Arqiva network (North of country)  and will work in the 900 ISM band at 868 MHz while others are on the O2 network. (South and central regions)    Most likely in the 900 band which is 900 (UL: 880-915).
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    MHRestorations:

    It looks to me that the fault applies to MEMERA2000 RCDs because they pre-date the current EMC requirements, and smart meters are built down to a price.


    I am not in the collander wearing brigade, but I have printed a notice to any potential smart meter fitters to call me FIRST, and affixed it to the current meter, and service head, along with my phone number. They will be told in no uncertain terms NOT to fit one, as they're not reliable. (I know nothing about dangers, not having investigated this, but unreliability is proven. They have electronics in, and that fails).


    Traditional electromechanical all the way baby!




    Yep I agree, the old solid clunky electro-mechanical stuff is more reliable. My 1979 electricity meter is still working fine after all these years, although I have had a recent letter saying that replacement is due.


    All of the old Voltage or current operated earth leakage circuit breakers that I have removed from older installations have still worked perfectly even after 40 years. Examples are the English made Crabtree L60 R.C.D. which is a BIG beast. Or the Crabtree E 60 V.O.E.L.C.B. built like a tank. Just electro-mechanical, no electronics and very reliable as a device.


    Yet I have come across many modern R.C.D.s that have failed in service, that won't trip off on test button use, or even on R.C.D. tester. One new R.C.B.O. blew up after being fitted from new when the test button was pressed in.


    Z.

  • 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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