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EICR Advice - Mixed Manufacturer MCB'S, mains switch and enclosure

Former Community Member
Former Community Member
Advice Please.

I run a residential mobile home park. The main swa cable from the meter box runs via an old-style fused wylex isolator switch to the consumer unit in the mobile home. As the old fused isolator enclosure is plastic (bakelite?) with no means of terminating with a swa gland I have been told by the Electrician doing the EICR's that these must be replaced with a metal enclosure fused isolator switch. I have another electrician replacing these but as some also supply electrics in the shed where the meter box is, we have been replacing them with what we thought were appropriate shower or shed consumer units. However, in some instances where there are no shed electrics, we have replaced the RCD in the consumer unit with a main switch from a different manufacturer and in other instances we have replaced MCB's with a different manufacturer to obtain the correct rating for its use. All MCB's/Switches are the same dimensions and line up on the buzz bar correctly. The EICR inspector has told us we can't mix MCB's or main switches. Is this correct or would this just be a C3 recommendation? Is it ok to use another manufacturer’s MCB's/Switches if they are all from the same manufacturer but the enclosure is from another manufacturer?

  • Former Community Member
    0 Former Community Member
    we have replaced the RCD in the consumer unit with a main switch


    That could possibly be more of a concern than different makes.


    Regards


    BOD
  • 0
    You either need the manufacturer's approval, or take on the design and testing responsibilities of BS EN 61439 yourself:

     


    536.4.203 Integration of devices and components:

    ... In low voltage assemblies to the BS EN 61439 series, e.g. consumer units, distribution boards, incorporated devices

    and components shall only be those declared suitable according to the assembly manufacturer’s instructions or

    literature.

    NOTE 1: T he use of individual components complying with their respective product standard(s) does not indicate their

    compatibility when installed with other components in a low voltage switchgear and controlgear assembly.

    NOTE 2: Incorporated components inside the assembly can be from different manufacturers. It is essential that all incorporated

    components should have had their compatibility for the final enclosed arrangements verified by the original

    manufacturer of the assembly and be assembled in accordance with their instructions e.g. the consumer unit,

    distribution board manufacturer. T he original manufacturer is the organization that carried out the original design

    and the associated verification of the low voltage switchgear and controlgear assembly to the relevant part of the BS

    EN 61439 series. If an assembly deviates from its original manufacturer’s instructions, or includes components not

    included in the original verification, the person introducing the deviation becomes the original manufacturer with the

    corresponding obligations.

     


    Having said that, I can't see it being more than a C3. Note that this is a UK-specific deviation from the harmonised standard. Other countries seem to get by without this extra rule.

  • 0
    As the old fused isolator enclosure is plastic (bakelite?) with no means of terminating with a swa gland I have been told by the Electrician doing the EICR's that these must be replaced with a metal enclosure fused isolator switch.

    I'd disagree that replacement of the switchfuses is the only option - other options exists - e.g. terminating the SWA into a separate steel enclosure, or even a plastic enclosure and use an earthing nut to make a connection to the gland. Such alternatives may or may not be best for your situation of course.

     
    Note that this is a UK-specific deviation from the harmonised standard. Other countries seem to get by without this extra rule.

    I think part of the reasoning is that there's a UK annexe to the standard that allows us to use CUs in locations where the fault current can significantly exceed the rating of the components (e.g. a CU fitted with 6kA or even 3kA MCBs can used in situations with up to a 16kA prospective fault current) and it's possible for different manufacturers to adopt different approaches to achieve that (e.g. some might co-ordinate protection with the supply side fuse, others might rely on the enclosure to contain arc products). If the situation is such that the prospective fault current is well within the capabilities of the individual components (e.g. MCBs) and everything physically fitted together OK, I'd view mixing as much less serious.


       - Andy.
  • 0
    I agree with Andy's first statement. Back in the days of plastic CU's it was common practice (well, I hope it was) to terminate SWA into a suitable adjacent adaptable box.
  • 0
    common practice (well, I hope it was) to terminate SWA into a suitable adjacent adaptable box.


    Indeed, and to keep it small, and to save on a joint and some faff, to cut the swa long so the cores carried on unbroken straight out of the other side of the metal box, now accompanied by a length of green and yellow instead of the armour, in some plastic trunking or conduit or  similar, from that point onwards to the supply or light switch or whatever, just like you would connect normal wiring in singles.

    Mike
  • Former Community Member
    0 Former Community Member
    Hi, Thanks for all the replies and information, I will relay this to the EICR electrician and see if he will agree to a C3 for this and if it is ok to use an adapter box between the switched fuse box and the SWA cable so that it can be properly terminated without the need to replace the switch. I also have a separate question with regards to wylex rewireable fuse boxes that I will post in a new subject. 


  • 0
    Do the homes need to be TT earthed?


    Z.
  • 0
    If the situation is a 'caravan park' or similar, there'd also be a requirement for individual 30mA protection for the supply to a residential park home. (708.415.1) - although the RCD can be close to the home (e.g. in a hook-up unit) rather at the start of the circuit.

       - Andy.
  • 0
    https://electrical.theiet.org/wiring-matters/years/2016/61-summer-2016/electrical-installations-in-caravancamping-parks-caravans-and-motor-caravans/


    Z.
  • 0
    There is probably much more value for money in replacement rather than spending time and money trying to make do and mend.


    What make are the original consumer units that you cannot source protective devices for?

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