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Topic Title: Installing A wrong Manufacture MCB
Topic Summary: Wrong Board
Created On: 23 April 2014 08:09 PM
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 23 April 2014 08:09 PM
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Ampman

Posts: 1009
Joined: 06 February 2006

How do you guys/girls ,

See the above ?

Cheers

This one is a alto WF Installed in a wylex nsb board ,

the pattern is the same & no strain on busbar

Cheers
 23 April 2014 08:29 PM
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OMS

Posts: 19618
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Well, in some circles it's a worse crime than wearing double denim.

Personally, I don't have an issue with it, but I wouldn't neccessarily agree to it on some jobs I get involved with - for a simple domestic however, it's no real drama

The principal argument is that you can no longer claim the 16kA rating for the DB - but in the vast majority of cases we don't need to anyway - by a long chalk

Regards

OMS

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Failure is always an option
 23 April 2014 08:33 PM
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dickllewellyn

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I have this debate regularly.

Realistically it probably works, but I'm afraid it will negate any type approval, warranty etc of both the MCB, and the consumer unit it is fitted in. Even fitting the same brand but different ranges is a no no as far as type approval goes. I personally wouldn't do it on a customers instalation unless power was needed for critical supplies and there was no other way to maintain power.

The choice is yours. Do it and take a chance, or order the right MCB and keep the insurance valid. I've done it before, and will probably do it again, just make sure if you end up fending off brown stuff that hit the fan that you have a good reason and can back it up is all I would say.

I even had a conversation with a Schneider rep on a similar issue stating that I was using universal grid dimmers in their switches. He was quite sure that even doing that would cancel out any warranty.

-------------------------
Regards
Richard (Dick)

"Insert words of wisdom and/or witty pun here"
 23 April 2014 10:04 PM
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peteTLM

Posts: 3144
Joined: 31 March 2005

Alto are rebadged wylex products for the WF chain.

Exactly the same

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Lack of planning on your part doesn't make it an emergency on mine....

Every man has to know his limitations- Dirty Harry
 24 April 2014 08:41 AM
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phantom9

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If the device is manufactured to a BS then it doesn't matter what brand is on the label. This nonsense about void warranty is another insurance driven propaganda. Mixing up different brands in a consumer unit IMHO is not going to matter as long as the pattern allows the device to sit properly on the busbar and allow the front cover to fit nicely. BS7671 requires devices to be manufactured to BS not brands. I don't know why this subject gets raised so often. In all cases the correct device with matching brand should be used but its no big deal if it complies with a BS. You cannot argue against that (although one character on here will no doubt).
 24 April 2014 08:47 AM
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daveparry1

Posts: 6169
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I completely agree with you on this one Phantom, obviously we like to use the same make where possible but no big deal if not available for some reason.
 24 April 2014 08:55 AM
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505diff

Posts: 143
Joined: 20 March 2006

I agree, if I fit a Hamilton grid dimmer in an MK grid I don't expect problems, just like fitting non MEM HRC fuses in an MEM switch fuse or A GE 2D lamp in a Philips fitting, I know most of the above are a standard fit, but if an MCB is the same pattern, as phantom9 points out what's the problem, maybe someone can post a link from a news story about a fire and insurance claim being refused because of mixed MCBs in the board. I'm off to check the tyres on my van as one maybe a different brand to the others, and I may not be insured!
 24 April 2014 02:01 PM
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OMS

Posts: 19618
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Originally posted by: phantom9

If the device is manufactured to a BS then it doesn't matter what brand is on the label. This nonsense about void warranty is another insurance driven propaganda. Mixing up different brands in a consumer unit IMHO is not going to matter as long as the pattern allows the device to sit properly on the busbar and allow the front cover to fit nicely. BS7671 requires devices to be manufactured to BS not brands. I don't know why this subject gets raised so often. In all cases the correct device with matching brand should be used but its no big deal if it complies with a BS. You cannot argue against that (although one character on here will no doubt).


Well - you have my view above.

It has to be said that characteristics of circuit breakers all complying with relevant standards can (and do exhibit) significantly different operating characteristics (the standard allows for this).

At less than 5 cycles (ie less than 0.1 seconds) the only way to ascertain what is happening in terms of energy let through is to test the device in anger using real fault currents.

Which is exactly what manufacturers do with thier equipment - it's called type testing. From there they can make legitimate claims about withstand.

What you can't do is substitute another device and claim it will perform in the same fashion as the original device although you can take a view on how it will perform and claim you have a partially type tested system.

As I said, for a simple domestic, I wouldn't worry unduly - for anything a bit bigger, I would have some concern and in the wrong set of circumstances, I would have some very real concerns.

So it's wise not to be totally cavalier regarding this mix and match approach - like all things in engineering it's never black or white - and rest assured that if the brown stuff hits the roundy roundy thing then manufacturers will drop you in it as deep as they can based on the flimsiest of get out clauses.

Regards

OMS

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Failure is always an option
 24 April 2014 02:17 PM
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dickllewellyn

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I'm sure I remember reading an artical about this recently. I can't remember if it was a Wiring Matters, or maybe in ECA today, or possibly on Voltimum website. I'll have a dig around when I've got less time and see if I can find it.

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Regards
Richard (Dick)

"Insert words of wisdom and/or witty pun here"
 24 April 2014 03:46 PM
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Yooj

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Here you go:

Click here



Yooj
 24 April 2014 03:50 PM
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OMS

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Joined: 23 March 2004

LMFAO - very good, Yooj - I needed that

OMS

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Failure is always an option
 24 April 2014 05:56 PM
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lyledunn

Posts: 617
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Actually my NICEIC IE pulled me on this matter recently. I was fully aware of the concern but failed to note it on an EICR. I stood my ground however and took OMSs view (in an appropriately non-cavalier way) that there was no serious concern in the particular circumstances that we were addressing. However, I would take a general view that mixing protective devices is undesirable. For example, the dolly can switch in different directions and thus may confuse which is off and which is on, especially where mounted on the vertical on three phase boards. I fell foul of mixing devices once where an RCD main switch was faulty and was replaced, no doubt innocently, with a similar device from another manufacturer. The two devices were identical other than for supply line and neutral. When I touched the neutral bar it nearly broke my arm!

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Regards,

Lyle Dunn
 24 April 2014 05:59 PM
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mawry

Posts: 222
Joined: 26 April 2004

and rest assured that if the brown stuff hits the roundy roundy thing

Regards

OMS



Made me cough my green tea up laughing. Cheers, just what was needed after a long day!
 24 April 2014 06:08 PM
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OMS

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Green Tea ? - I bet u'r Mam didn't give you that, now did she ?

What's wrong with Glengettie,then - lovely brew when made with good Welsh water

OMS

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Failure is always an option
 24 April 2014 06:48 PM
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Smith249

Posts: 362
Joined: 09 September 2004

How do you guys feel about using all same brand internal devices & bus bar for the main switch and RCBOS/MCBS but in a different brand enclosure?

To me that should make no difference as long as its a standard din-rail type enclosure?

I ask this as I have started using those compact double pole rcbos sold by a member of this forum, however I use them in an MK enclosure as I don't like the 'plain' enclosures.

I would hate for someone to look at one of my jobs and think its a bodge because of this, but I can't find another way of doing the boards I want i.e all RCBO (hate split-load) and an nice looking enclosure.

 24 April 2014 11:42 PM
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alancapon

Posts: 5761
Joined: 27 December 2005

If you are within the fault rating of the mcbs, then it is unlikely to be an issue. If the fault rating of the mcbs is lower than the supply can provide, then you are relying on Annexe ZA of the standard for consumer units, which specifies that the assembly can be type tested to prove that it can withstand higher fault currents. Obviously a manufacturer will only type test their own devices as an assembly.

You need to remember that following a fault, an mcb only needs to operate once, it does not need to be suitable for continued use. As part of the mcb tripping at this high current, the consumer unit needs to contain any parts or arcs that are expelled from the mcb during the tripping process - this is where the risk comes in.

Regards,

Alan.
 25 April 2014 06:19 AM
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GeoffBlackwell

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First note that BSEN 60439-3 is now replaced by BS EN 61439-3:2012 (£146.00) - you would need to check that Annex ZA and its application has not changed.


This is really quite simple - it just depends on your attitude to risk .

Looking at 'domestic installations' using a 'Consumer Unit' first.

It comes down to fault level - this must be known. We can measure it if we are confident of our ability to do that accurately, or we can take the DNO supplied figure. However, it is very likely that the DNO will simply state that it is up to 16KA as this ball park figure allows for most foreseeable changes to network configuration.

If we take our own figure we might have to justify this in the event of any failure.

If the fault level is greater than the mcb rating but less than or equal to 16kA - we can, depending on your view of risk, choose to use mcbs rated at less than 16kA provided that we meet the conditions of BSEN 60439-3

In the UK a national adjustment to Euro Norm 60439-3:1991 allows this under Annex ZA - note that this does not have an indefinite life.

It applies under strictly defined conditions to what we call Consumer Units - the rest of Europe call them Customer Distribution Boards as the French think that 'Consumer Units' are something that you eat .

"Customer Distribution Board: An integrated assembly, for the control and distribution of
electrical energy, principally in a household or similar premise,
incorporating manual means of double-pole isolation on the incoming
circuit(s), with polarity observed throughout. They are designed for use
exclusively with specific protective devices on the outgoing circuits, and
type-tested for use when energized through the specified 100 amp fuse.
Note Generally known in the UK as a Consumer unit."


The Annex goes on to define all of the test parameters and conditions that must be applied.

This deviation is not just a Europe thing - we had something similar in our own old standard: BS 5486 - Part 13.

The main point about Annex ZA is that it requires a type test to be carried out by the manufacturer. It is hardly surprising that, when asked, they all state that the use of different types of mcbs to those they have used in their tests (regardless of who made them ) fails to meet the conditions imposed by Annex ZA.

Next installations with fault levels above 16kA or that cannot be described as 'household or similar premise' - your on your own

So if you use mcbs that do not meet the manufacturers requirement - quite simply you transfer any risk from the manufacturer to yourself. If you have, and intend to maintain even in retirement, good professional Indemnity insurance, then sleep tight .

Regards

Geoff Blackwell
 25 April 2014 08:20 AM
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mawry

Posts: 222
Joined: 26 April 2004

Originally posted by: OMS

Green Tea ? - I bet u'r Mam didn't give you that, now did she ?



What's wrong with Glengettie,then - lovely brew when made with good Welsh water



OMS


No Mam didn't, I have phases through the day, morning is coffee(black - strong), mid afternoon tea, after 5, green tea. Started drinking it a few years back as something different. It took a few month to get used to it.


Ampman, take each situation and assess and action from there. I'll be surprised if you do anything different than you already are.

On domestics sleep easy, what's the highest FL you've come across?
Of course if I worked for a board, sorry, consumer unit manufacturer I'd be accusing you of heresy!
;-)
 25 April 2014 08:26 AM
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lyledunn

Posts: 617
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Geoff,
Does the type test consider the entry of cables? I am thinking particularly of the common practice of bringing cables through the back of wooden board and then through a large aperture in the back of the consumer unit. It would be hard to imagine that such a set up would meet the type test requirements, irrespective of devices used.

-------------------------
Regards,

Lyle Dunn
 25 April 2014 08:49 AM
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GeoffBlackwell

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Lyle

Not specifically but that should be covered in installation instructions.
The test is specific about the devices fitted and the cables connected to them.

Here is an example of some of the detail

8.2.3.3 Test sequence.
The Customer Distribution Board shall be subject to the following two tests A and B with the outgoing way fitted with a final circuit protective device of the maximum thermal current rating If the final circuit protective devices have a short-circuit rating less than 16 kA, two further tests A and B shall be carried out with a device of the minimum thermal rating fitted. In addition, if the Customer Distribution Board is designed to accept different types or ranges of outgoing devices, each type shall be further tested separately.

The two tests are as follows:
a) Test A. With the circuit connected as described above, with all fuses in place and all circuit-breakers closed, the test voltage is applied with the point-on-wave controlled to provide initiation of the fault at between 0° and 20° (electrical) on the rising voltage.

b) Test B. A further short-circuit operation shall be applied after
suitable preparation as indicated in table dependent on which of the
alternative results of test A is achieved. If circuit-breakers are included
in the Customer Distribution Board, the test shall be applied by
reclosing a circuit-breaker with the test circuit energized. If fuses are
used, the test shall be as in Test A.

During the tests cheesecloth shall be placed on the outside of the
enclosure at all openings, e.g. arc vents and handles. There shall be no ignition of the cheesecloth.
© BSI 2007


Regards

Geoff Blackwell
IET » Wiring and the regulations » Installing A wrong Manufacture MCB

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