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RCD socket outlet.

Former Community Member
Former Community Member
Hi all,
Any comments on this one most welcome!
A customer wants me to replace an existing one gang 13 amp socket outlet with a double.
The problem is that there's no rcd protection there, so i'm thinking that as I am in effect adding a socket outlet I should fit an rcd protected one?
If I were replacing like for like it wouldn't bother me at all but the fact it's going to be a double makes me think an rcd protected one is the thing to do, just seems a bit ott to fit one rcd protected socket when there are probably 20 others that aren't rcd'd!
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    OK. I was trying to be helpful having some knowledge of the issue. Clearly my advice is un-welcome.
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    John Peckham:

    OK. I was trying to be helpful having some knowledge of the issue. Clearly my advice is un-welcome.




    JP, I hope that it is not I who has upset you.


    My 15th Edn installation has SRCDs e.g. in the conservatory, where risk is higher than indoors. If one fails, may I replace it, or should I bring it up to current standards?


    Frankly, I hope not.

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    The law only requires you not to make an installation any more dangerous than it already was.

    There is no need to bring it fully to current standards if it is unreasonable to do so.

    If you belong to NICIEC, their house rules may suggest otherwise, but that is not law.
  • Former Community Member
    0 Former Community Member
    We should remember that members of the public with no training are perfectly entitled to change the accessories to any installation. If an untrained person chooses to replace a standard socket outlet plate for one with additional protection in the form of a RCD then that must surely be a good thing, regardless of what is upstream. 

    However, John is right to highlight the change to the regulation to professional installers. I don't think it is a mistake by the committee. In my view they are righting a longstanding wrong whereby the SRCD was designed not to compensate for an electrical installation which couldn't provide safe protection, but was designed as a supplement to an already good installation. Proffessional electricians are being encouraged to upgrade and improve existing installations rather than just opt for the soft option of fitting a SRCD on the end of it. 

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    A socket outlet or SCFU with a built in RCD will only provide RCD protection to what is connected downstream of if.


    So for example if the main earth conductor is missing or defective a fault on an existing non-RCD protected circuit elsewhere in the installation such as a lighting circuit could raise the touch voltage on the metal case of an appliance downstream of the RCD socket or SFCU to a dangerous level.


    Now for the REALITY CHECK there is EXACTLY THE SAME RISK if the circuit has a RCD or RCBO upfront of it in or alongside the consumer unit.


    So any 30 mA RCD device can only be installed with confidence if the circuit and equipment downstream of it it effectively earthed so that a fault elsewhere in the installation won’t raise the voltage on the CPC and connected class I appliances above 50 volts and in a TT installation there is a suitably rated and effective RCD main switch.


    Do not forget the basic requirements for safe electrical installation work.


     Andy Betteridge 


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    effectively earthed so that a fault elsewhere in the installation won’t raise the voltage on the CPC and connected class I appliances above 50 volts



    so practically never then?

       - Andy.
  • 0

    mapj1:

    The law only requires ...




    Same question as ever - which one?

  • 0
    Lol.


    The IET have upped it to 70 volts when it suits them, you get the general gist of things.


    All RCD devices produced to British Standards are equally effective a providing additional protection.


    The problem is that the  British Standards committee writing the standard for RCD protected sockets and SFCU failed at the first fence when they did not consider the purpose and usage of the devices, failure to produce an usable product was inevitable.


    Try finding an application guide for the products produced to the new standard ?


    Andy Betteridge
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    All 30 mA RCD devices produced to British Standards are equally effective at providing additional protection.
  • 0
    An extract from a article by the NICEIC in the Professional Electrician Magazine from the 10th July 2019.

    “Typically, the common form of protection for circuits supplying underfloor, wall and ceiling heating systems will be ADS. An RCD having characteristics complying with Regulation 415.1.1 shall be used for fault protection (I∆n ≤ 30 mA) (Regulation 753.411.3.2). This also meets the requirements of Regulation 753.415.1, the need for additional protection. It is a fundamental requirement of circuit design that overcurrent protection is provided, (Section 430 refers).



    Typically, in older installations fuses to BS 3036 or circuit breakers to BS 3871 maybe found. Where this is the case and it is not practical to include RCD protection at the consumer unit a 13 A RCD spur maybe installed locally from an existing circuit as shown in Fig 2. Furthermore, consideration should be given to the power rating of the heating system and the implications affecting the existing circuit (Regulation 433.1.204).”


    Please feel free to write a critique of the article.


    Andy Betteridge 


     




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