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Topic Title: Home made DBs
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Created On: 15 January 2013 06:14 PM
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 18 January 2013 09:16 PM
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sparkingchip

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Scenario:

You turn up at a rented house, a plumber is replacing an existing shower on an existing circuit.

The circuit is supplied by a Henley block in the tails to the main consumer unit which in turn has tails going to a 30mA RCD main switch and a B32 MCB in a enclosure.

You determine that the RCD has failed and will not trip under test using either the button or test meter also the MCB should be a B40.

Do you:

A) Replace the whole shower consumer unit, enclosure, RCD and MCB?

B) Replace the RCD and MCB with two that you have on the van from a different manufacturer to the enclosure which you are retaining?

Andy
 18 January 2013 09:22 PM
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Martynduerden

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Originally posted by: Cremeegg

TextAs such, this distribution board / control panel may not have been constructed to the requirements of BS EN 61439 and may not therefore meet the standards required in BS7671:2011 as amended.


Just to be thoroughly pedantic - the green book is still BS7671:2008 incorporating Amendment No 1: 2011. It is not BS7671:2011.

Many thanks Zs for originating yet another hugely entertaining thread that has, as ever, taught me plenty. Thanks to those who have contributed as well - my learning never stops.

Couldn't even get myself snowed in today - I was working in my neighbours.



That's not pedantic! Thanks I never even realised.

-------------------------
Regards

Martyn.

Only a mediocre person is always at their best



www.electrical contractors uk.com
 18 January 2013 09:52 PM
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Legh

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Ah, my learned Legh, would that it were as you describe.


May I refer you to my second signature ...... All will become clear .. ish

Just to be thoroughly pedantic - the green book is still BS7671:2008 incorporating Amendment No 1: 2011. It is not BS7671:2011.


It is as you say, but I shouldn't think that anybody here would not know what you're on about .


Legh

-------------------------
Why do we need Vernier Calipers when we have container ships?

http://www.leghrichardson.co.uk

"Science has overcome time and space. Well, Harvey has overcome not only time and space - but any objections."
 18 January 2013 09:53 PM
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Zs

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Neither Andy, you wait for him to finish cos he's probably got the neutral and earth taped up together on his not yet energised circuit. Which is why the RCD is not tripping

Zs
 18 January 2013 10:02 PM
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sparkingchip

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 18 January 2013 10:20 PM
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Legh

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Originally posted by: sparkingchip



Look old boy,
Its Friday night and a smiley face is just not good enough......
We need to see improvement in your replies, otherwise we'll need to put you on CPD......



Legh

-------------------------
Why do we need Vernier Calipers when we have container ships?

http://www.leghrichardson.co.uk

"Science has overcome time and space. Well, Harvey has overcome not only time and space - but any objections."
 18 January 2013 10:31 PM
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sparkingchip

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You touched a nerve there, I'll send you a link I just sent Zs!
 19 January 2013 05:27 AM
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GeoffBlackwell

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Originally posted by: sparkingchip
Scenario:
You turn up at a rented house, a plumber is replacing an existing shower on an existing circuit.

The circuit is supplied by a Henley block in the tails to the main consumer unit which in turn has tails going to a 30mA RCD main switch and a B32 MCB in a enclosure.

You determine that the RCD has failed and will not trip under test using either the button or test meter also the MCB should be a B40.

Do you:
A) Replace the whole shower consumer unit, enclosure, RCD and MCB?

B) Replace the RCD and MCB with two that you have on the van from a different manufacturer to the enclosure which you are retaining?
Andy


Your choice, but bear in mind that the manufacturers have set their face against option B.

They will refer you to the fact that these are Type Tested Assemblies (TTA) to BS EN 60439-3. In addition they will say that, being UK units, their short circuit performance is the subject of a UK A deviation to the standard and that this requires a very specific test.

So if it goes pear shaped - if you are a limited company and have a good legal team you might not be afraid of appearing in court when a man in a lemon suit with dark sun glasses enters for the room .

If not you risk everything you have.

Regards

Geoff Blackwell
 19 January 2013 10:17 AM
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Zs

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I always install new for my clients, so I expect that I would change the shower DB for a new one. The only time I might not do that is if I choose to use an RCD from stock which trips quicker than the one in the main board, if there is one in there. As you know, I keep a stock of timed and tested RCDs and like to put ones which are quite soft in sheds.

It would also depend on the state of the existing small board. If a Crabtree, sentinel, proteus or indeed an old wylex (pre dating the recall), I'd change it. Oh, and of course I'd use a hager so I could have the spirit level for my collection.

However, most of us carry a selection of breakers so we'd probably be able to muster up a matching pair.

Worse case is a non-matching breaker for a few days while a match is sourced. that's why none of us are rich; We're constantly haveing to pop back to things like this.

No, I would not change the entire shower unit. that would be reserved for the plumber if the new one turns out to be faulty.

Geoff, you make an interesting point about legal. I'll always give consideration to whether or not I would be comfortable explaining any of my quirky actions. But I'm not so sure about the man in the Lemon suit. Is he dodgy? I reckon he sounds so.


Now I'll have a look at my email to see what you might have sent me Andy.

Zs

Edit: Oh that old Chestnut. They say they'll, phone, they say they'll write, they promise you the world, they say they emailed you a link.....Nada Andy, you didn't send me nuffink. I might have to dump you now.

Edited: 19 January 2013 at 10:35 AM by Zs
 19 January 2013 10:38 AM
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GeoffBlackwell

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Geoff, you make an interesting point about legal. I'll always give consideration to whether or not I would be comfortable explaining any of my quirky actions. But I'm not so sure about the man in the Lemon suit. Is he dodgy? I reckon he sounds so.


Oh yes he is dodgy - ask OMS

Regards

Geoff Blackwell
 19 January 2013 11:14 AM
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alanblaby

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How about different names on the CB/RCBOs, but are made on exactly the same production line?
M2 and Proteus are the same iirc, Niglon and Excel do the same RCBOs, apart from different branding.
CEF do their own branded CBs - clearly these are just re-branded 'main make' CBs, is it argued that these shouldn't be replaced with what is exactly the same, apart from a different name on the front?
 19 January 2013 11:23 AM
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GeoffBlackwell

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As I said it's your choice.

If you are sure they are the same specification and that the manufacturer will confirm that and accept any liability then fine - if not you take on the risk. If you think it is worth it - fine.

The risks here are probably pretty small - the chances of failure are relatively small and the risk of consequent legal action is small.

However, if it all goes horribly wrong you might be taking a big hit.

Regards

Geoff Blackwell
 19 January 2013 12:43 PM
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sparkingchip

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I haven't got around to changing my Avatar lately, some of you will remember that the picture currently to the left is of a cable cut out from a Wylex consumer unit burning whilst I hold it in a pair of pliers.

Now that is where it could all go wrong, I can see it clearly.

If you used a RCD and MCB from a manufacturer that ensures its plastic consumer unit units are made from flame retardant, self extinguishing plastic and put them into a consumer unit that will readily burn and produce choking thick black smoke that is a risk to the occupiers of the building or fire fighters then the RCD/ MCB manufacturer will say you are responsible for the outcome if there is a fire. Whilst the CU manufacturer will talk about the choice of internal components and torque settings.

Andy

Zs I sent you a link by PM on this site, it is information open to all, but perhaps best not fully discussed here. A cautionary tale of the possible outcome of being over helpful, then finding you can't cope with everything piled onto you.
 19 January 2013 12:47 PM
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rocknroll

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For you guys on this level basically the sharp end, electricians, inspectors, plumbers etc; the issue of type tests, approvals etc; has little relevance whether you construct a bespoke distribution board or use equipment that comes from different manufacturers, the legal argument is far more basic than this and that is did you use equipment that was supplied to you as 'fit for purpose' and if the goods you use display the necessary CE and BS markings you are permitted to assume they are 'fit for purpose'.

Dont worry too much about the references to 'court' you have more protection than you know and cases of this nature are generally dealt with and resolved under the civil tribunal umbrella, all your required to do is use your experience, judgement, commonsense and the tools available to you to do a good job for your customer and in essence the majority of you do this without question despite the increasing 'back stabbing' that is rife in the trades.

regards

-------------------------
"Take nothing but a picture,
leave nothing but footprints!"
-------------------------
"Oh! The drama of it all."
-------------------------
"You can throw all the philosophy you like at the problem, but at the end of the day it's just basic electrical theory!"
-------------------------
 19 January 2013 01:46 PM
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rogersmith7671

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I agree with what Rocknroll said.

regards
 19 January 2013 02:07 PM
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kj scott

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What RnR is saying here is misleading; these things do at times go legal; and if or when you get to court you will be looking pretty incompetent if you are unable to confirm conformance with the relevant product standards.

I have acted for clients on number of occasions that have gone legal, in fact one was with regard to exactly this situation, it cost the installation contractor in excess of £100K; and they were working to a consultant's specification. The installer used similar statements in his defence to those, but was unable to prove conformance to product standards, so lost.

-------------------------
http://www.niceic.biz
 19 January 2013 03:35 PM
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rocknroll

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Not really misleading I did point out that most are dealt with under the civil tribunal method but some obviously progress to court, the advantage with the tribunal method which is being used much more than it was is that it is cost effective, also other issues can be introduced not within the specific law such as risk.

One has to remember thankfully this is a two way street and not only have contractors been the ones to be accused of competence issues but many inspectors and 'expert witnesses' have also.

regards

-------------------------
"Take nothing but a picture,
leave nothing but footprints!"
-------------------------
"Oh! The drama of it all."
-------------------------
"You can throw all the philosophy you like at the problem, but at the end of the day it's just basic electrical theory!"
-------------------------

Edited: 19 January 2013 at 03:42 PM by rocknroll
 19 January 2013 10:24 PM
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kj scott

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Which is why I have always said that inspection and reporting is a specialist field.

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 20 January 2013 10:53 AM
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Zs

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http://www.mcg-products.com/pa...section_contents.html

Morning.

The link above is to MCG, with whom I am not familiar and who are the manufacturer of the RCBOs and TP breakers in the board we have been looking at. The RCBOs have already cost them about £40 each so we're looking at about £1,800 spent on those plus the cabinet etc. and plus labour.

I'm trying to find a viable solution which would use the existing breakers. So as to reduce the cost of the new board. RCBO protection is essential.

Deep Joy, it seems that MCG only provide distribution boards up to twelve ways. I need 16.

I'm considering removing the contactors into a separate compartment and I gather there are some din rail mounted timers behind the cover which didn't show in my photo which I would also prefer to move out. By doing that I hope to be able to re use the existing contactors and timers which may not be of the same brand.

Do you know otherwise about MCG only going up to 12 ways?

I would rather not split into two distribution boards. Mostly for aesthetic reasons. Load is low, these are mostly lighting and small power circuits.

Zs
 20 January 2013 11:30 AM
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OMS

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when a man in a lemon suit with dark sun glasses enters for the room


But I'm not so sure about the man in the Lemon suit. Is he dodgy? I reckon he sounds so


LoL - lemon suit !! - never in court, corporate charcoal with a burburry document case bulging with carefully crafted notes, maybe.

just a few of my ramblings below:

Distribution Board number 666 which is situated on the mezzanine floor in riser cupboard 101, is bespoke (i would avoid the word bespoke, it is an assembly of component parts arranged to provide protection and control of relevant circuits - bespoke suggests that it's a custom design compliant with relevant standards) (You should state the loads served by the assembly - external lighting may have less relevance in terms of importance to the client than dealer floors or safety services - if this thing serves safety services then state that, because it may well end up falling foul of other relevant standards as well). This means that it has been specially (not sure about that word in here) assembled from a variety of component parts and is not an off-the-shelf product. (i wouldn't mention off the shelf - this is an assembly of components undertaking the function of a typical Type B distributon boad in accordance with BS EN 60439-3:1991+A2:2001 and/or BS EN 61439-1 and 2 :2011. The CE markings on the component parts do not constitute an over-all CE marking.......?

As such, this distribution board may not have been (does not appear to have been ?) tested to XXXXXXXX? and may not meet the required standards of BS7671 and XXXXXXXXX (compliance with relevant product standards and hence BS 7671 etc cannot be ascertained)?

Put in the stement from Andy J or similar as to what is "usual" ??

Put in a statement here that describes the implications of this DB not conforming to relevant standards



Because of this, I (we ?, use the body corporate not your individual status) advise (recommend) that (evidence is provided to confirm etc) (you are issuing this report to your client - what he instructs the installer to do is his business) you ask the installer to provide evidence that distribution board 666 meets the required standards which are detailed above.

Test reults shown on the attached schedule are as measured from the assembly of distribution board 666 at 01/04/1901 (what purpose do the test results of circuits have to the scenario - you might only be concerned with fault levels) and I take no responsibilty for problems caused by failure of combined parts or any unknown elements. (not required, your report disclaimer will indicate that the report is for the sole use of your client - you cannot opt out of that responsibility - and failure of the component parts when used as an assembly will be covered above, so clearly not your responsibility anyway.)



If you'd like a peer review on the report, ping it over and I'll pick it up at Sleepy Hollow sometime tomorrow.


Aren't MCG effectively City Electrical Factors - selling rebadged equipment under the MCG brand ?

I'd be pretty certain that 12way TP&N Type B boards are the range limit

If you relocate the contactors and timers do you still need 36 outgoing ways ? - particularly if a bit of load balancing is going on ?

Regards

OMS

-------------------------
Failure is always an option
IET » Wiring and the regulations » Home made DBs

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