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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?

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    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.
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  • 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.
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