Blankety blank

[ericmark]

This has been raised on another forum, and I don't really have an answer, we are told to retain the type tested status that a consumer unit should only be fitted with items authorised by the manufacturer which in real terms means items made by the same manufacturer.

So if the blanks are push in type, even if you can remove them without a tool then you can't replace them with another manufacturers blanks, so if some one fails a CU (code 2) due to blanks that can be removed without a tool, what is the next step?

Consumer protection act 2019 springs to mind, and getting the council involved, however the big question is if there is in real terms any CU where the CU manufactured blanks can be removed without a tool?

Also is it permitted to use random blanks found in ones tool box? Lets face it fitting these

is easy, but these

not so easy, so very temping to fit push in blanks, even if it is an MK CU.

 

[EFLImpudence]

Do MK also make push-in types?

 

[ericmark]

I don't really know even with push in types if you could easy remove without a tool, I say easy, as I am sure using my elbow I could easy smash a plastic consumer unit and gain assess without use of a tool, some one talked about pushing the blanks in, but that would break the blank same as elbow can smash the CU, I don't say kick as ones shoe is a tool.

But since we normally have a screwdriver to hand, I have never tried to remove a blank without a tool, it looks possible, but again really looking at child assess so smaller fingers and weaker.

So not even sure push in blanks is an issue, but if it is, then also the manufacturers have an issue if they produce a blank which is not fit for purpose.

 

[EFLImpudence]

Some of them don't actually just "push in".

They have to be rotated slightly and fitted to the cover before it is replaced so that when in place they cannot simply be pulled out.

 

[studentspark]

They have to be rotated slightly and fitted to the cover before it is replaced so that when in place they cannot simply be pulled out.

That is the case for the metal blanks

But I have yet to find any of these in hard plastic, which would be useful for plastic CUs

 

[EFLImpudence]

Wylex NH.

https://www.discount-electrical.co....356/wylex-nh-series-twist-fit-blanking-module

 

[studentspark]

Oh yes.... thank EFLI

 

[EFLImpudence]

On the subject of the strangely named "type testing";

if all manufacturers use the same requirements and conditions for type testing, does that mean that parts are, in fact, interchangeable - if they physically fit properly.

 

[studentspark]

I am finding it very difficult to get CUs at the moment especially the smaller boards.


A generic CU enclosure with din rail, would be good, and then you could populate it however you wanted.
(All same make of course)
And if MCB manufactures had a set bus bar arrangement, like they do for the din rail mounting, that would be most welcome.

 

[bernardgreen]

The thought of a metal blanking plate falling onto the bus bar in a metal CU doesn't worry me as no one would be fitting a blanking plate with the main switch ON. Or maybe someone might.

 

[JohnW2]

The thought of a metal blanking plate falling onto the bus bar in a metal CU doesn't worry me as no one would be fitting a blanking plate with the main switch ON. Or maybe someone might.

As I've often said, if it has not already happened I feel sure that it is only a matter of time before someone is killed (or seriously injured) as a a result of the (IMO 'stupid', as well as impossible) requirement for domestic CUs to be made of 'non-combustible' material, coupled with the (IMO equally 'stupid') decision of manufacturers that they could only approximate to ('pay lip service to') this impossible requirement by using metal.

Kind Regards, John

 

[seasickstevie]

... doesn't worry me as no one would be fitting a blanking plate with the main switch ON. Or maybe someone might.

Working on a 36-way DB, it could cause a major issue to shut all the PCs down in an office, just to simply fit a missing blank. That's why I'd prefer the plastic blanks. At lease if it pushes inside (which they sometimes so easily do) it's not going to bridge the busbar.

 

[JohnW2]

This has been raised on another forum, and I don't really have an answer, we are told to retain the type tested status that a consumer unit should only be fitted with items authorised by the manufacturer which in real terms means items made by the same manufacturer. .... So if the blanks are push in type, even if you can remove them without a tool then you can't replace them with another manufacturers blanks ...

For a start, I don't know if/where there are any specific requirements in relation to the nature and scope of 'type testing' of CUs (certainly not in BS7671), or whether manufacturers can simply 'do their own thing' but, not having seen such requirements (if they exist) I am far from convinced that the 'type testing' undertaken will necessarily involve any 'tests' which are of any relevance to 'blanks'. The only specific reference to 'what is tested' in BS7671's definition is (understandably) ...

... an assembly of one or more fuses, circuit-breakers, residual current operated devices or signalling and other devices proven during the type-test of the assembly as suitable for such use...

However, that is not necessarily an exhaustive list, so it doesn't really help.

More generally, I wonder whether the belief that "domestic installations must have ('type-tested') Consumer Units" is perhaps another example of 'over-interpretation' of the regs?

I may (well ) be missing it, but I'm not aware of anything in BS7671 which explicitly requires that DBs in domestic installations have to be ('type tested') "Consumer Units" (as defined). Perhaps the closest appears in the infamous 'non-combustible' reg, which says:

421 PROTECTION AGAINST FIRE CAUSED BY ELECTRICAL EQUIPMENT
... 421.1.201 Within domestic (household) premises, consumer units and similar switchgear assemblies shall comply with BS EN 61439-3 and shall: ... <silly 'non-combustible' requirements > ...

... and, since I don't know what (if anything) BS EN 61439-3 has to say about 'type testing', cannot be sure what it means/implies. The only other (often cited) reference to such matters is the reg which relates exclusively to the breaking capacity of devices, which says ...

536.4.201 Fault current (short-circuit) ratings. ...

The relevant fault current (short-circuit) rating of the assembly should be equal to or exceed the maximum prospective fault current at the point of connection to the system. .......... For an installation with a 230 V single-phase supply rated up to 100 A that is under the control of ordinary persons, switchgear and controlgear assemblies shall either comply with BS EN 61439-3 having a suitable fault current (short-circuit) rating for the maximum prospective fault current at the point of connection to the system or be a consumer unit incorporating components and protective devices specified by the manufacturer complying with BS EN 61439-3, including the 16kA conditional short-circuit test described in Annex ZB of the standard

However, this is merely a dispensation which allows ('type tested') CUs in certain domestic installations to have devices with lower breaking capacities than would otherwise be the case (per first sentence of 536.4.201). I therefore don't think this reg compels a domestic installation to have a (type-tested) CU.

I therefore wonder if I'm missing something - since, as above, it seems to me that the regs might well allow a domestic installation to have a DB which was not (or did not remain) a ("type tested") CU, provided only that it contained devices of adequate breaking capacity. Even if that were the case, 421.1.201 would presumably still require the DB to be 'non-combustible', because I imagine that it would qualify as a "similar switchgear assembly".

[In passing, as I've noted before, one could say that 536.4.201 does not actually apply to my installation because, unusually for a domestic installation, although it is "under the control of an ordinary person", it is a 3-phase supply ]

Kind Regards, John

 

[ericmark]

If one instructor says pass and another fail, hard to show who is correct, but where a manufacturer says pass, and inspector says fail, one would hope the manufacturer is correct, and if not also the type testing also is flawed.

But we have seen with cladding how a manufacturer seems to have got it wrong.

For the owner, best bet likely to get local authority involved, but for the inspector not so easy.

I think I would code C3 as a coward.

 

[JohnW2]

I think I would code C3 as a coward.

Are you talking about a 'blank' from the 'wrong' manufacturer?

If so, when you coded it (as C3) which regulation would you cite as having been violated?

Kind Regards, John