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Is RCD required on an addition

Ok, we've just had a new utility room and downstairs toilet made and the downstairs ring-main has been extended to provide sockets, the chap who did it was suitably qualified. 

Now someone else has said that he should have fitted an RCD to meet modern regulations and I think that that would constitute best practice however, is it necessary?

According to BS7671:2018 On-Site Guide  Sect 7.8:

“Installers adding or amending circuits in dwellings will encounter older consumer units, i.e. those not complying with Regulation 421.1.201, for many years to come.  It is important that installers do not advise the replacement of consumer units simply because they do not comply with the current version of BS7671.  To ensure the ongoing use of such enclosures and assemblies, the installer must ensure the following:

Also BS 7671 Sect 651.2 Note 2 “Existing installations may have been designed and installed to conform to previous editions of BS7671, applicable at the time of their design and erection.  This does not necessarily mean that they are unsafe”.

Should he have fitted RCDs?
  • 'downstairs sockets' you say? I assume that the exsisting consummer unit has no facility to house a RCD?

    Well these sockets could be utilized to supply power outlets to garden appliances. So I would say that on the probability that they could be used it would be wise to install a RCD to protect those sockets.


    Legh
  • In effect the new work is not to current standards, and cannot be certified as such. That on its own is not illegal of course, but is a bit surprising, and may affect your insurance premium; after all RCDs have been de-rigeur on new socket circuits for use by ordinary persons since before 2008, and on sockets that may supply equipment outdoors (i.e. in the room with the back door) for more than 25 years.

    If it was mine I'd have insisting on upgrading to RCD protection, but it all rather depends what you asked for as "can you do it cheap?" and "can you do it well ?" gets two different jobs.


    There are a number of approaches that could make it closer to or meet the current standards - RCD sockets example  protect the users of appliances but not the wiring in the walls (common for a quick upgrade of existing wiring).

    The new work could have been wired as an RCD spur  example  but this suits small areas with modest loads, such as a conservatory.

    If the consumer unit has MCBs, it may be possible to replace one for an RCBO.

    It is possible to add an RCD in a box alongside the existing fuseboard, though this looks a bit industrial.   


    edit afterthought

    what installation paperwork (test results/ minor works certificate etc ) did you get with this job?

  • Former Community Member
    0 Former Community Member
    My view is that the regulations do not insist that all aspects of the existing installation are brought up to current regulation standards as they were presumably installed to meet a previous versions of the regulations which was fine. However if new sockets have been installed then this work should meet the regulations at that time regardless of if the sockets are installed as a new circuit or an addition to an existing circuit. An RCD would be also be required for any new wiring supplying a luminaire (411.3.4) or also if the cable is T&E buried in plaster (depending on how this is done) (522.6.202).
  • The extended lighting circuit needs RCD protection as well as the extended socket circuit. 


    Your best option is probably to replace the consumer unit. 


    Andy B.
  • The extended lighting circuit needs RCD protection as well as the extended socket circuit. 


    Almost certainly the best option is to replace the consumer unit. 


    Andy B.

  • Robert Eagle:
    Ok, we've just had a new utility room and downstairs toilet made and the downstairs ring-main has been extended to provide sockets, the chap who did it was suitably qualified. 

    Now someone else has said that he should have fitted an RCD to meet modern regulations and I think that that would constitute best practice however, is it necessary?

    According to BS7671:2018 On-Site Guide  Sect 7.8:

    “Installers adding or amending circuits in dwellings will encounter older consumer units, i.e. those not complying with Regulation 421.1.201, for many years to come.  It is important that installers do not advise the replacement of consumer units simply because they do not comply with the current version of BS7671.  To ensure the ongoing use of such enclosures and assemblies, the installer must ensure the following:

    Also BS 7671 Sect 651.2 Note 2 “Existing installations may have been designed and installed to conform to previous editions of BS7671, applicable at the time of their design and erection.  This does not necessarily mean that they are unsafe”.

    Should he have fitted RCDs?




    Read what you have written and you should realise that reference to the OSG is about consumer units with plastic enclosure and does not refer to the requirements for RCD protection.


    Andy B.