Class 2 consumer units

[Sidewinder]

Unusually, I'm with Essex.

The response you had from the NICEIC, is not that which was given at Elexx coventry, nor Sandown Park, during the IET forum there.

If you are going to buy an MCB and put it in an enclosure, then the assembly of enclosure & MCB must meet the requirements of EN 61439-3

There are many ways, probably the easiest is to use them from the same OEM, who say that they are compatible.

 

[ProDave]

If you were to buy a metal 2-way box and put an mccb in there. How does that comply with BS EN 61439-3? Unless both the enclosure and the mccb were made by the same manufacturer and were tested as such under that standard. They can't be AFAIK since they do not constitute an assembly and do not come under that standard.

On that basis you can't take any empty enclosure and put an item of switchgear into it. So the wholesalers better stop selling individual components because we are not allowed to use them.

 

[Rob_the_rich]

Well, just got off the phone to the iet tech and they are of the same opinion it seems as slipshod and slapdash, in that a plastic enclosure upstream of the consumer unit does not comply. Purely because of the amount of load the terminals, especially the neutral, are subjected to. They have no problem with an RCD in a plastic enclosure downstream of the CU as this would only be carrying the load of one circuit, although if the circuit would likely be under continuous load, a metal enclosure would be worth considering.

They did say, as the designer, I could follow the advice of the niceic and install a plastic box, but that would be my decision. Legal speak for "on your head be it".

What a complete tosh this all is.

 

[Sidewinder]

...

What a complete tosh this all is.

...

Yep!

 

[ProDave]

Well, just got off the phone to the iet tech and they are of the same opinion it seems as slipshod and slapdash, in that a plastic enclosure upstream of the consumer unit does not comply. Purely because of the amount of load the terminals, especially the neutral, are subjected to.

As we are talking domestic single phase, I always though phase and N current would be the same.  So it would seem not?

Or are they admitting N terminals are not made as well as phase terminals?

Or electricians routinely fail to tighten N terminals?

Or could they be hinting that the design of CU neutral bars is inadequate, which begs the question why not address that concern, rather than the tin box idea.

 

[Essex1]

And thus we now come full circle again.  

 

[Rob_the_rich]

Unusually, I'm with Essex.

The response you had from the NICEIC, is not that which was given at Elexx coventry, nor Sandown Park, during the IET forum there.

If you are going to buy an MCB and put it in an enclosure, then the assembly of enclosure & MCB must meet the requirements of EN 61439-3

There are many ways, probably the easiest is to use them from the same OEM, who say that they are compatible.

Yeah, the iet guy touched on that, and I must admit that I did think that an item and its enclosure could/should be defined as an assembly, but as mentioned before the examples given as in scope are modular afaik, and the standard refers to "distribution boards".

This does raise a good point about buying a metal box and installing anything that fits though. sbsdave, forum sponsor, would know all about this I am sure.

Edit; that came out wrong, no disrespect to Dave, I meant he might have input.

 

[Sidewinder]

Rob,

Who was on the IET helpline today by the way?

You don't need to put it in open forum, you can PM if you like, I might know them that's all.

 

[Sharpend]

Would there be anything wrong with locating an RCD externally in a plastic IP box, akin to a mobile home setup, would the amendment be satisfied as the plastic enclosure would not cause a mass fire if this was the case? 

Just asking.......?

 

[SBS Dave]

Hi Rob, thanks for the invite.

I have 2 identities on the TEF Forum. My main one is SBS Dave, a Forum Sponsor who  would not wish to cross swords with existing and potential

customers. The other one is DaveS ( which I use on the NAPIT Forum), which puts me into the debate on an equal footing with the rest of you.

This is Dave S commenting (IMHO).

BS7671 421.1.201 states that "consumer units and similar switchgear assemblies" must comply with BSEN61439-3. SO THAT IS THE ACID TEST.

However, BSEN61439-3 is specifically for a "Distribution Board intended to be operated by ordinary persons (DBO)" Since an Isolator Switch Assembly, (which is probably sealed), is not intended to be used by ordinary persons, it cannot comply with BSEN61439-3 and cannot therefore be classed as "similar switchgear" The Standard describes a DBO as an ASSEMBLY used to distribute energy in domestic (household) applications and other places where operation is intended by ordinary persons. An isolator switch is for isolation only and not for distributing energy. It further states that, in the UK, this type of DBO is known as a Consumer Unit. To the best of my knowledge, no manufacturer test an isolator switch to BSEN61439-3 and describes it as a Consumer Unit, which further indicates it is out of the Scope. (IMHO)

With regard to the OSG, pages 7-11 goes to great lengths to describe its limitations, as being for Domestic and small Industrial and Commercial installations, so of course it is going to be a "dumbed down" version of BS7671 in those areas relevant to its Scope. I am one of those idiots who use it, even though I have been in the Industry for 57 years and used to assess electricians annually for competence. It was an essential publication to own for Membership and was required reading. It probably still is. It may use rules of thumb rather than the adiabatic equation, but  not all electricians are comfortable with formulae involving squares and square roots. Hopefully, many of you will share my views on the OSG.

Finally, I am going on holiday on 23 February for one week. If I do take a holiday, it may p*ss off some Forum Members. If I don't take a holiday, it will p*ss off my wife.        No contest!!

Dave S

This is SBS Dave

I shall be out of the Office from 23 February until 1 March 2016. Could my Forum customers take this into account, with regard to any upcoming jobs, for  which you may wish to use my equipment.

SBS Dave

 

[Rob_the_rich]

Thanks DaveS,

niceic tech says installing an mccb in a plastic enclosure upstream of a CU is not in scope of amd3

iet tech says installing anything upstream of a CU is in scope of amd3 because of the amount of load.

I agree, a pre-CU isolator would not be in scope, iet doesn't because of the load.

What a pickle.

 

[Sharpend]

So it would appear that the infamous Niceic are not as close to the engine of this industry as they would like people to believe? 

Overall ll it's a great job by those that have only to sit in a chair for work to screw it up for those that have only to actually WORK.