they always seem to be happy with our switch gear in there 


There's your answer!


Unless you think BS7671 includes DNO meter boxes!


Regards


BOD

Also the KMF  complies with BS EN 60947-3 ; it is not bothered with the dreaded 421.1.201, so can be of a sensible construction.?

Unless you think BS7671 includes DNO meter boxes!

Surely BS 7671 covers everything after the supply terminals, whatever it happens to be? I presume the KMF will be after the meter.


I guess the meter box isn't of itself made of non-combustible material. 421.1.201 applies to 'domestic (household) premises' - so I guess it's down to whether you think something within the outside leaf of a wall counts as part of the premises. The normal dictionary definition usually includes all buildings and land - but the usual BS 7671 interpretation generally excludes things fully outside of a habitable building (such a detached outbuildings). So definitely vague to my mind.


If the house is of conventional masonry construction with nothing but another brick wall behind the meter box the risks are probably low, but if it was say timber frame with nothing but breather membrane, softwood and PIR/PUR foam insulation behind the meter box, I might not be quite so confident. So generalizations can be difficult. What about masonry construction but with flammable cavity fill?


   - Andy.

Cheers guys.

It is not manufactured as an assembly to BS EN 61439-3 as it is not a consumer unit

Interesting - I thought most would have considered a switchfuse as coming under the heading of 'similar swicthgear' - being pretty much identical in function to a 1-way CU (DP incomer, feeding one OPD, suitable for use at the origin of an installation and so on).


So if it doesn't comply with BS EN 61439-3 isn't that technically another contravention of 421.1.201 - which not only asks for consumer units and similar switchgear in domestic premises to have non-combustible enclosures but for them to comply with BS EN 61439-3 as well.


Steel versions are still readily available - e.g. https://www.screwfix.com/p/wylex-100a-domestic-switched-fused-unit/5290j

that Wylex one for example appears to meet the requirements of  BS EN 61439-3 as well as 60947-3 according to https://www.electrium.co.uk/media/20151123152755_0_Wylex Domestic Switch Fuse Unit.pdf.

   - Andy.

"It is not manufactured as an assembly to BS EN 61439-3 as it is not a consumer unit "



Interesting - I thought most would have considered a switchfuse as coming under the heading of 'similar swicthgear' - being pretty much identical in function to a 1-way CU (DP incomer, feeding one OPD, suitable for use at the origin of an installation and so on).

Like a shark AJ ?


It , the KMF, is not manufactured as an assembly to BS EN61439-3, as it is not a consumer unit.


However, if there is only a KMF and no consumer unit- unlikely- then the intended use changes and would not be in the spirit of 421 etc.


There are no steel moulded 800KMFs; though there briefly was, though to what BS is lost in time.


Some may chose to manufacture a switch fuse to 61439-3, as opposed to the specific KMF.


In the KMF, you cannot change the fuse holder. It is all in a moulded assembly. You could change the fuse, but that is not resetting a device as you would in a consumer unit. For most intended use the KMF is providing HRC fuse  protection usually upstream of a DBO  in a domestic. It is usually not touched by ordinary persons; they would be accessing the consumer unit. The KMF is just a bigger, beefier device than your 13 amp switch fuse connection unit and we do not usually require those to be steel.

In the way that there is no multitude of thin final circuit wires routed like spaghettii, some pulled violin tight from side to side in front of others, I suggest the risks from one of these are NOT in any way similar to a consumer unit. Let us remind ourselves in the pic below what one a "good" example of a modern post part P (look at the new colours ! ) twin RCD installation can look like. (and remind ourselves that some total shyster charged good money to leave it like that. Funny that word fails the spell check. You  know what I mean. )


And you are not putting your switch indoors. Do it well and do not worry too much.



The risk is simply not similar in any way.

Mike.

How the hell does someone walk away from a job like that.