Mismatched MCBs C2 or C3?

[Deleted member 142255]

From BS7671 current edition

It also crops up in the inspection schedules. So basically, if you fit anything not approved by the original manufacturer, you take on the role of original manufacturer and it is YOUR responsibility to prove the type testing of that unit and device combination.

 

[JohnW2]

What code would you put? If any

That's fortunately a decision I'll never need to make. However, answering the question hypothetically and particularly given what Bazza has shown me (whilst I'm separated from my copy !) what BS7671 has to say, I imagine that I would feel reasonably compelled to give it a C3 - but happy in the knowledge that, in any event, such a code is 'harmless' even with rented accommodation..

However, I think that anyone who gives a C2 (to anything) needs to remember what it means - i.e. that they truly believe that what they are coding is "Potentially dangerous and requires urgent remedial action" - and I'm farfromconvinced that EICR inspectors always do 'remember that'.

In the present context, as I wrote, if there are signs of any true 'problems' within the CU (e.g. devices not fitting properly or showing signs of thermal damage or whatever) , then that should be coded accordingly (quite possibly a C2) but if there is no suggestion of any 'problem' then I personally feel it would be somewhat stretching things to conclude that the situation was "potentially dangerous and requiring urgent remedial action".

 

[Deleted member 142255]

That's fortunately a decision I'll never need to make. However, answering the question hypothetically and particularly given what Bazza has shown me (whilst I'm separated from my copy !) what BS7671 has to say, I imagine that I would feel reasonably compelled to give it a C3 - but happy in the knowledge that, in any event, such a code is 'harmless' even with rented accommodation..

However, I think that anyone who gives a C2 (to anything) needs to remember what it means - i.e. that they truly believe that what they are coding is "Potentially dangerous and requires urgent remedial action" - and I'm farfromconvinced that EICR inspectors always do 'remember that'.

In the present context, as I wrote, if there are signs of any true 'problems' within the CU (e.g. devices not fitting properly or showing signs of thermal damage or whatever) , then that should be coded accordingly (quite possibly a C2) but if there is no suggestion of any 'problem' then I personally feel it would be somewhat stretching things to conclude that the situation was "potentially dangerous and requiring urgent remedial action".

Read, study and understand note 2!

If the device has not been approved by the original manufacturer then it is YOUR responsibility to type test with the device you have fitted.

 

[pete01]

Read, study and understand note 2!

If the device has not been approved by the original manufacturer then it is YOUR responsibility to type test with the device you have fitted.

If you fitted it yes if you found it like that(on an eicr) then what you gonna do....

 

[JohnW2]

From BS7671 current edition

Thanks. It's a pity that I didn't have my book to hand

It also crops up in the inspection schedules. So basically, if you fit anything not approved by the original manufacturer, you take on the role of original manufacturer and it is YOUR responsibility to prove the type testing of that unit and device combination.

So it seems. I can't say I've ever looked, but do 'empty CU enclosures' really come with instructions as to what devices are approved for being put into the box.

I do suspect that an awful lot of this is purely 'commercial', with the big boys having found ways of producing products and technical/'safety' arguments to keep them (probably 'just'!) on the right side of anti-competition laws! I have to say that I was somewhat shocked/surprised when I first discovered, very many moons ago, that devices to go into CUs/DBs were not standardised so as to be interchangeable. Let's face it, we even accept the interchangeability of generic medicines from countless different manufacturers, and one can't really get a lot more 'safety-critical' than that.

 

[Deleted member 142255]

If you fitted it yes if you found it like that(on an eicr) then what you gonna do....

Following note 2, Appendix 6, and BPG4, I would C2 it as its isn't approved for that particular application. If it is in the MI's then C3

 

[Deleted member 142255]

Thanks. It's a pity that I didn't have my book to hand

So it seems. I can't say I've ever looked, but do 'empty CU enclosures' really come with instructions as to what devices are approved for being put into the box.

I do suspect that an awful lot of this is purely 'commercial', with the big boys having found ways of producing products and technical/'safety' arguments to keep them (probably 'just'!) on the right side of anti-competition laws! I have to say that I was somewhat shocked/surprised when I first discovered, very many moons ago, that devices to go into CUs/DBs were not standardised so as to be interchangeable. Let's face it, we even accept the interchangeability of generic medicines from countless different manufacturers, and one can't really get a lot more 'safety-critical' than that.

BS7671 is not compulsory, however this comes from BS EN 61439 which is a harmonised standard and is compulsory.

I love unqualified people - not!

 

[pete01]

Following note 2, Appendix 6, and BPG4, I would C2 it as its isn't approved for that particular application. If it is in the MI's then C3

I suppose if its 1 mcb in a house and you can get a correct new one for a tenna then that's great...

But if theres 50 mcbs in a warehouse your gonna get well it's been alright for the last 20 years mate...

 

[JohnW2]

Read, study and understand note 2! ... If the device has not been approved by the original manufacturer then it is YOUR responsibility to type test with the device you have fitted.

You're a bit too fast in your replying See the question I've just asked you in relation to "noite2".

However,in relation to "it is YOUR responsibility", we're talking about coding by an EICR inspector (who does not 'fit' anything as part of his/her inspection, and may well have had no previous dealings with the installation) - so it is "the responsibility of SOMEOINE ELSE" , isn't it?

 

[Deleted member 142255]

I suppose if its 1 mcb in a house and you can get a correct new one for a tenna then that's great...

But if theres 50 mcbs in a warehouse your gonna get well it's been alright for the last 20 years mate...

Been there and got that Tee shirt.

 

[Deleted member 142255]

You're a bit too fast in your replying See the question I've just asked you in relation to "noite2".

Can't keep up?

However,in relation to "it is YOUR responsibility", we're talking about coding by an EICR inspector (who does not 'fit' anything as part of his/her inspection, and may well have had no previous dealings with the installation) - so it is "the responsibility of SOMEOINE ELSE" , isn't it?

You said

That's fortunately a decision I'll never need to make. However, answering the question hypothetically and particularly given what Bazza has shown me (whilst I'm separated from my copy !) what BS7671 has to say, I imagine that I would feel reasonably compelled to give it a C3 - but happy in the knowledge that, in any event, such a code is 'harmless' even with rented accommodation.

You haven't a scooby because you don't do it or have never done it.

Fitting an unapproved device can lead to fire and death. If you are inspecting then you carry the responsibility for your decisions and codes.

 

[JohnW2]

BS7671 is not compulsory

Indeed not, at least not in law - although many electricians are constrained by scheme membership to comply with it. However, in the present context EICRs are based oin the requirements of BS7671/

, however this comes from BS EN 61439 which is a harmonised standard and is compulsory.

"compulsory" in what sense?

I love unqualified people - not!

Give it a break! In my time, and in many fields, I've come across a good number of 'unqualified' people whose knowledge, skills, intelligence and competence (and common sense!) are a lot greater than those of many iun the field who have 'qualifications' coming out of their ears!

In some fields, I am ;highly qualified' but I fully accept that, in those fields, there are some people who are 'unqualified' (or, at least, a lot less qualified than I am) who are superior to me - in knowledge, intellect, 'competence or whatever - and I would never dream of trying to use their 'lack of qualification' against them.

Over the decades and centuries, many of the most important ('game-changing') discoveries and inventions in science, technology, medicine etc. have come from 'unqualified' people.

 

[Deleted member 142255]

"compulsory" in what sense?

The standard that applies to the manufacture of low voltage switchgear.

 

[JohnW2]

Different make of a MCB only breach manufacturers instructions however a consumer unit will not comply with BS7671 if filled with different makes. Every different type MCB are type tested to their breaking capacity with their own make of devices. .... Quick think, the exit point for the arc during a fault current is also manufacturer specific. They will insure nothing impedes this in there consumer units. Fitting different devices in a consumer unit could impede this.

I really can't help suspecting that most people have been 'taken in' by what appear to be solely theoretical arguments (even if some of them seem a bit far-fetched)

I have asked many times, in many places, over the years, but without any particularly useful answers .... has anyone ever come across a situation in which they really believed it probable that some ('dangerous') problem had arisen because a device in a CU (which 'fitted perfectly' and had been installed properly) was of the wrong brand?

I also strongly suspect that the 'type testing' is not anything like as compressive as people seem to think particularly in relation to the sort of theoretical issues you mention (arcs), when position, nature and loading of neighbouring devices could well be relevant. I find it hard to believe that they test all possible combinations of devices in all orders and over a wide range of loading for each of them (which probably would tot up to thousands of scenarios to 'test') - yet all they seem to do is to 'approve' certain devices (of their own manufacture) without any information upon what ordering etc. of them has been tested, and therefore 'approved'.

 

[JohnW2]

The standard that applies to the manufacture of low voltage switchgear.

That's a red herring. No-one would manufacture and sell something which did not comply with the relevant product standard - so no 'populated' CU/DB would be sold that contained 'non-approved' devices.

We're talking of what happens to (devices within) the CU/DB subsequent to it being manufactured and sold, and that it totally outside of the control of whoever manufactured it.