This discussion is locked.
You cannot post a reply to this discussion. If you have a question start a new discussion

Type A rcd . EICR coding ? etc

Hi Guys.   Not been on for a long time, just had a bit of a search and couldn't really find anything so thought i would ask and see what you all thought.


1.  Are we or will we be coding type AC rcd's if there are LED's or induction hobs, lots of electronics  etc  present.

2. How much DC leakage does it actually take to saturate an rcd and cause  problem?

3. How much does a standard LED lamp or induction hob  leak ?

If we test an AC RCD with no load and it's fine then re-test it with all LED lights, induction hobs etc turned on and it operates correctly could we then say that it is ok with a note on EICR  OR EIC if installing any of the above.  


Obviously also on an EICR if the RCD then doesn't operate with it all on it becomes a C2 ?


Any thoughts



Gary
  • In answer to Q1, it's no code from me because the installation is safe (assuming it passes the required tests).

    314.1 (iv) suggests that the problem should be addressed by division into (more) circuits.
  • For general purposes, type AC RCDs may be used (see 531.3.3.). If I was erecting a new installation, I wouldnt use type AC but unless it was one of those situations where type AC are precluded, say EV charging, I wouldnt code in a periodic inspection. I would, however, simply note the type on my schedules.
  • Obviously also on an EICR if the RCD then doesn't operate with it all on it becomes a C2 ?

    From a safety point of view it can't be worse than not having the RCD fitted in the first place - which in my book would be C3 if it's only for indoor additional protection, it would only be a C2 if it's intended to feed mobile/portable equipment outdoors or is being relied upon for ADS (e.g. a TT system).


      - Andy.
  • OK Thanks.    How do we feel about additions and leaving the installation less safe than we found it by fitting LED or induction hobs then ?    


    Not sure how extra circuits help either if they are all on same rcd. 



    Cheers guys
  • aligarjon:

    OK Thanks.    How do we feel about additions and leaving the installation less safe than we found it by fitting LED or induction hobs then ?    


    Not sure how extra circuits help either if they are all on same rcd. 


    I don't think that nuisance tripping is unsafe. Extra circuits help if they are separately protected - i.e. loads of RCBOs.


    Ooh, how I love my 15th Edn installation with a couple of SRCDs and no more. ?


  • The idea that electronic loads may produce DC currents is probably wrong. DC current really needs to be DC, not some kind of AC waveform which is not symmetric. This is a difficult point which is not easy to understand, but the proof of a problem is not at all clear. Information requested!
  • The NAPIT book "ECIR Codebreakers" takes a different view and gives a C2 for the following description.... "RCD fitted is type AC and has pulsating DC currents present from connected equipment such as EV, PV, switch mode power supplies (SMPS), domestic appliances with VSDs, etc. which may/will mask fault current and prevent the type AC RCD from operating"


  • sparkiemike:

    The NAPIT book "ECIR Codebreakers" takes a different view and gives a C2 for the following description.... "RCD fitted is type AC and has pulsating DC currents present from connected equipment such as EV, PV, switch mode power supplies (SMPS), domestic appliances with VSDs, etc. which may/will mask fault current and prevent the type AC RCD from operating"


    It isn't just a matter of masking. I have a VSD which simply does not work with a type AC RCD (in a socket) - the moment I press the start button, it trips. That doesn't justify a code.


    Are we sure that these devices mask the RCD?


    My understanding is that type AC RCDs will trip on a pulsating AC fault current, but they may not trip on a pulsating DC fault current? Type A RCDs should trip in the event of either occurring.


    How could the code for the presence of a type AC RCD be worse than the one for none at all? ?


  • It isn't just a matter of masking. I have a VSD which simply does not work with a type AC RCD (in a socket) - the moment I press the start button, it trips. That doesn't justify a code.

    Most probably unwanted tripping would have resulted in the owner making arrangements to get it working, so I would be surprised if this was part of a ECIR.

    Are we sure that these devices mask the RCD?

    I don't know, I can only go on the advice our industry provides, like this from the IET https://electrical.theiet.org/wiring-matters/years/2019/77-september-2019/which-rcd-type/ and this from Hager https://hager.com/uk/support/regulations-18th-edition/selection-of-rcd-types  There are also some good videos from E5 and John Ward on youtube. These would suggest that selection of RCDs is relevant.

    My understanding is that type AC RCDs will trip on a pulsating AC fault current, but they may not trip on a pulsating DC fault current? Type A RCDs should trip in the event of either occurring.

    Agreed

    How could the code for the presence of a type AC RCD be worse than the one for none at all? ?


    I would not look at it in isolation, other factors would be considered, so could be C2 or C3

     


  • Again more clever marketing by manufacturers effecting the wiring regulations. Front line electricians are told to sell these new devices with no detailed information or facts to base there proper deployment.

    Manufacturers solving a problem that doesn't exist. Along with surge protection and afdd.