Consumer Unit Change

[Midwest]

I don't own gn1, I'm slowly buying and reading them all however gn1 is not one I've bought yet.

Reading that further confuses me. all conductors "should" not "must" therefore surely not required? I understand that l and n could cause issues but I don't see a problem with main earth coming through a separate hole.

I do hope elecsa can give me a definitive answer tomorrow at 8am. I'm worried about finishing on time of I have to reroute it all now.

Stress levels through the roof right now.

Don't stress yourself. You'll see from that thread, the difference in interpretation of the regs. Some say the regs are in black & white. Well that's one thread, shows that's not the case.

GN1 refers to 'Live cables ..........if entering ........through different holes', defining 'Live' cables bought on the debate. It also says 'All the conductors of a circuit should generally follow the same route'. (GN1 last paragraph page 97).

You'll see from #105 from that thread, the OP rang NIC technical Advice on regulation 521.5.1 - http://www.electriciansforums.co.uk/threads/advice-on-regulation-521-5-1.103579/page-8. and was advised;
'The context of the appropriate protective conductor in regulation 521.5.1 doesnt include a main earthing conductor as its not part of an a.c circuit in bs7671 as it is classed as a separate entity'. That was a year ago, so can't seem advice changing dramatically, unless technical argue as much as us!

 

[Nickj]

If I could rewind a couple of weeks id opt to do a full rewire. So much easier to control every element that way. I have a rewire job lined up for the new year (assuming I can pass Tuesday!).

Murdoch if questioned by an assessor how would you answer 521.5.1 with regard to the main earth entering separately?

The regs aren't very explicit it seems nor is gn1 (based in the earlier quote I gave from midwest).

 

[Pat H]

Wiska M40 IP68 IP Rated Brass Gland for Terminating Tails into Consumer Unit | eBay - http://www.ebay.co.uk/itm/Wiska-M40-IP68-IP-Rated-Brass-Gland-for-Terminating-Tails-into-Consumer-Unit-/182008076235?hash=item2a6086d7cb:g:cr8AAOSw7aBVCxvT
Is a gland that can optionally take a 16mm earth as well.

 

[Midwest]

PS; get that EIC written up again in your best's handwriting in black ink. You might be re-doing the form electronically after you assessment, but the inspector will be pouring all over your forms.

Have you got all the other documents required for your assessment?

 

[Nickj]

That form was purely a working copy and is in pencil. Todays task is to write it up neatly (2 copies). I'd like to print it however not been able to find a non pdf version that I can type onto.

All other paperwork will be found (pretty sure I know where it all is) or printed (insurance in email form at present) today and put into a folder for him to browse through.

Should I call elecsa tomorrow or do you all think (I take on board it's an opinion) that it will be fine as it is?

How would you answer if questioned about the regulation specifically?

Could this result in a fail or deferral?

 

[Pat H]

The argument for the earth being with the live conductors is that in a fault condition current will flow in the earth and if separate eddy currents will flow. However in a fault condition the small time the current flows won't be enough to generate enough heat to be of concern.

 

[Risteard]

Given that the minimum insulation resistance is for the installation I would prefer to measure all circuits in parallel. Also BS7671 DOES require the Earthing conductor to be collectively surrounded with the live conductors where entering a ferromagnetic enclosure.

Recording the individual circuit readings is the best way to go ..... because if you called back later for, say tripping, you can compare readings to see if any have changed.....

There is NO requirement to bring the main earth through the same aperture as the tails..... so don't waste your time making the call. There are special glands that allow you to bring the tails and earth together but that's a "nice to have" .

 

[Nickj]

A global ir with rcbos would be difficult to achieve since the test would pick up the rcbos?

I was always taught to test each circuit separately.

It seems I'm going to have to call elecsa regarding the main earth and it seems highly likely that tomorrow I'm going to have to tear the install apart to route the main earth through the rear entry with the tails.

Not what I wanted to hear, I'm stressed enough as I is without having to tear apart the work I did

 

[Pat H]

You could leave it as it is. Discuss with the assessor and based on his input decide if re-routing the earth is required.
You don't want to do all that work for him (or her) to say it wasn't an issue.

 

[Risteard]

It may be impracticable with RCBOs but then you need to consider the effects of resistances in parallel through calculation to verify compliance.

A global ir with rcbos would be difficult to achieve since the test would pick up the rcbos?

I was always taught to test each circuit separately.

It seems I'm going to have to call elecsa regarding the main earth and it seems highly likely that tomorrow I'm going to have to tear the install apart to route the main earth through the rear entry with the tails.

Not what I wanted to hear, I'm stressed enough as I is without having to tear apart the work I did

 

[Octopus]

It seems I'm going to have to call elecsa regarding the main earth and it seems highly likely that tomorrow I'm going to have to tear the install apart to route the main earth through the rear entry with the tails.

Suggest you read 521.5.1 (BYB) again... first sentence ends "are contained within the same enclosure".... then the 2nd sentence says "where such conductors enter a ferrous enclosure, they shall be arranged such that the conductors are only collectively surrounded by ferromagnetic material"

Which is a loads of gobbledygook!

The muppets who write and update BS 7671 should have reviewed such regs when the AMD3 CU's were introduced.....

IMHO I don't think you should pull anything apart..... before your assessment, if and I say if you get pulled up on this, have your decision making criteria rehearsed. If the assessor disagrees get him to spell it out why he thinks the L, N and E should be together when entering a metal CU. You do get time to correct any issues....

I've said this on many times, BS 7671 should be submitted to the Plain English Society, and be reviewed BEFORE the next amendment as the whole document is littered with such issues.... that's what happens when many people write single documents - for the best example look no further than the Bible.

 

[westward10]

Don't even bring it up, unless the assessor questions it.

 

[Nickj]

Thank you. If I left it as it is and the assessor didn't like it even after a discussion then would that result in a re-assessment or would I be given the time to alter it and submit photographic evidence that it has been altered after which I'd be accepted?

Not entirely sure what to expect. I know it can be an outright fail or there are instances that photographic evidence of corrected non conformance can allow you to be accepted.

 

[Midwest]

If I could rewind a couple of weeks id opt to do a full rewire. So much easier to control every element that way. I have a rewire job lined up for the new year (assuming I can pass Tuesday!).

Murdoch if questioned by an assessor how would you answer 521.5.1 with regard to the main earth entering separately?

You could tell a little white lie, and say you rang Tech support, and was given the answer as in #105 of 'that thread'. When I ring tech support, they never ask for you or company name or EPP number. I could be Mrs Miggans from the pie shop, for all they know (no jokes.... please ).

I agree with Murdoch, 521.5.1, in this context, is not clear. MFI use to write better assembly instructions than BS7671 submissions. You could ring tomorrow, if you have time to change it, if tech support rules in favour of the red corner. But don't if its going to take some time. The day would be better spent, making sure you have everything in places, and just get all the basics set up in your head, for the questions you'll get asked.

Think you need to put that to one side for now. Worst case scenario, is your have to have the inspector back for tea & biscuits.

Good luck, and go and have a beer. Resolves most things in my personal experience.

 

[Midwest]

Thank you. If I left it as it is and the assessor didn't like it even after a discussion then would that result in a re-assessment or would I be given the time to alter it and submit photographic evidence that it has been altered after which I'd be accepted?

Not entirely sure what to expect. I know it can be an outright fail or there are instances that photographic evidence of corrected non conformance can allow you to be accepted.

It's difficult to tell from here sat looking at screen, but it appears your approach is quite professional, which I expect would be reflected in your work. Which is the main thing they are after. Doubt if there is anyone on this forum that does everything explicitly as BS7671 says (if you can understand everything it says!).

 

[westward10]

I know it is a bit late but did you try to see if you could pull another earthing conductor through using the old one to pull it through.

 

[Nickj]

That was my original plan of action westward however the old 6mm earthing conductor was packaged with the tails in the form of 2 core and earth.

I then tried to follow the same route as the tails thinking it would be easiest however my rods couldn't get through so I took a different route and used trunking along with fire clips where needed.

Knowing what I know now I could have chased out the final approach and entered through the rear with the rest of cables.

If I redid it that's exactly what I'd do. whether it is worth redoing tomorrow with assessment on Tuesday is quite the dilemma. I could end up with a less neat install due to the constrains than I have now.

I'd like to avoid a reassessment at all costs due to it meaning another 6 week wait for appointment etc.

Damned if I do damned if I don't

 

[Richard Burns]

From the point of view of the assessor, if he asks about this, you have cogent and reasoned statements indicating that you had considered the issues and decided that the situation was safe and compliant with BS7671 as far as you understand it.
If you can state this with the assessor at the time and therefore show that you are competent then this should be acceptable.
If the assessor still decides that rectification is necessary then, because you are already demonstrating competence, a simple photographic resolution should be sufficient.

 

[Pat H]

I agree in the unlikely event the assessor feels the earth needs re-routing and you agree to that change a simple photo by email should be enough. They maynot even need that.

 

[Nickj]

That's a relief. I'll leave it as is and argue my case if it comes up.

Now to find all my paperwork...

 

[Midwest]

Remember the biscuits, although they seemingly they're a bit health conscious now, the last one declined my triple choc hobknobs

 

[Nickj]

Selection of biscuits tea and coffee all available. All of the finest quality. If only people still accepted brown envelopes haha

 

[Midwest]

From the point of view of the assessor, if he asks about this, you have cogent and reasoned statements indicating that you had considered the issues and decided that the situation was safe and compliant with BS7671 as far as you understand it.
If you can state this with the assessor at the time and therefore show that you are competent then this should be acceptable.
If the assessor still decides that rectification is necessary then, because you are already demonstrating competence, a simple photographic resolution should be sufficient.

That's what I said, lie through one's teeth

 

[Richard Burns]

That's what I said, lie through one's teeth

Oh dear, oh dear!
If you can't baffle them with brilliance, then befuddle them with.. "cow excrement"

 

[westward10]

I am assuming there will be some spare ways at the new board. How do you intend to fill them, I always stick a breaker in them much better than blanks which the assessor may not like.

 

[Nickj]

There are spare ways and I have filled them with blanks.

I did consider this carefully and thought about spare breakers, those new dummy breakers and blanks.

I decided that I'd follow manufacturers instructions and inside the box there were blanks to be used to fill spare ways.

Blanks fit into the board snugly and whilst they could be removed it wouldn't be accidentally as you do need to manipulate them a little to get them out.

Bs7671 does say to follow manufacturers instructions and so if there is an issue with these surely it's for the manufacturer to answer?

This board is mounted high enough to stop children playing but low enough for an adult to operate it at arms reach.

Overall I am happy with this choice...

 

[Andy78]

What make is the board ?
Some push in blanks may comply and some may not. I always use dinrail mounted blanks to ensure a good secure hold and compliance.

I recently used used a BG garage board that was supplied with push in blanks. They could be flicked out easily with a fingernail, so not compliant, no matter what the instructions said.

BS7671 asks that products are selected for their suitability and compliance so the onus is on the designer/installer.

 

[Nickj]

It's a bg board. I've tried to remove them and whilst I could it took a fair bit of wrangling to do it. Switching over to blank mcbs wouldn't be much of a task.

I'm guessing any make blank would fit? The bg ones aren't in stock and so I couldn't get them in time.

These MK ones are in stock and I could put them in tomorrow http://www.NoLinkingToThis/p/mk-blank-mcb-pack-of-5/71995#product_additional_details_container.

If nothing else it would be something to talk to him about and distract him from the main earth

 

[Andy78]

No idea if the MK blanks would fit. I tried Hager blanks and although they provided an IP2X fit, they didn't really fit and I wasn't happy with it. I ended up buying more mcbs to plug the gap.

 

[Midwest]

Oh common, last time I tried removing CU push in blank covers, I broke my precious finger nails . Din rail ones are better, but you still need a tool with the former.

Anyways, give this bloke a break. ''Don't have nightmares, do sleep well",

 

[Midwest]

Oh dear, oh dear!
If you can't baffle them with brilliance, then befuddle them with.. "cow excrement"

Sometimes Richard, you brilliance misses the point.

 

[Andy78]

Oh common, last time I tried removing CU push in blank covers, I broke my precious finger nails . Din rail ones are better, but you still need a tool with the former.

Anyways, give this bloke a break. ''Don't have nightmares, do sleep well",

I held this opinion until I tried the metal clad BG garage board recently. Most push in blanks are very solid.
You can't sweepingly approve or disapprove any type of product though, especially when it comes to BG. They really do only take a stern look to make them fall out.

 

[westward10]

A modular DIN rail blank of fit a breaker. The only cover blank worth their salt are the twist fit ones which cannot be removed with the cover in place.

 

[Octopus]

I use the Wylex metal blanks - they can only be fitted before the cover is fitted. And I fit them to other makes of CU

 

[DPG]

Trouble is then you need to bond them. Daz. (popcorn ready).

 

[Pat H]

Trouble is then you need to bond them. Daz. (popcorn ready).

Ok I'll bite... As long as the metal enclosure has exposed metal at the rear of that blanks connection won't it be bonded via that?
And if it does need a bonding cable will 10mm be enough

 

[DPG]

The metal to metal contact between enclosure and blank would be inadequate . Daz

 

[Pat H]

The metal to metal contact between enclosure and blank would be inadequate . Daz

A rivet maybe?

 

[DPG]

Brass nut and bolt with flylead to earth bar. Daz

 

[Wilko]

I'm concerned about introducing another conducting surface - it can't be good can it? I've been filling spaces with mcb or a plastic dummy.

 

[Pat H]

Brass nut and bolt with flylead to earth bar. Daz

10mm or go the whole hog and make it 16mm? after all it could contact a pretty serious bus bar...

 

[Nickj]

Hi all,

I've fitted the mk blank mcbs. They look ok (not as neat as the plastic blanks in my humble opinion).

Just to clarify one point.

They fit neatly but I would say just about fall short of ip4x. I am correct in thinking for the mcbs and main switch I only need ip2x? (I'm way above ip2x, close to ip4x).

Thanks all for your help, tomorrow is the day and so I'm pretty much out of time

 

[Pat H]

Only the top is ip2x the rest is ip4x

 

[Nickj]

Sorry pat confused by your response?

 

[DPG]

Wrong way around maybe. Daz

 

[Pat H]

Sorry yes the other way round.
Only the top is ip4x the rest is ip2x
My bad

 

[westward10]

I use the Wylex metal blanks - they can only be fitted before the cover is fitted.
These are the blanks I was referring to didn't realise Wylex now do them in metal, normally fill spares with mcbs. So this begs the question are plastic blanks still acceptable with the metal enclosure.

 

[Nickj]

Thanks all, I'll post tomorrow to let you know how it goes.

Plastic blank mcbs meet all requirements. Let's not forget the mcbs themselves are plastic.

The plastic blanks I can see being an issue as they can be removed without the use of a tool to varying degrees, some are great but really the ones I had could be removed with some wrangling.

The plastic blank mcbs cannot be removed without a tool amd therefore are entirely up to the job.

The reason I didn't use the metal ones are for the reasons discussed above. The board is painted and so they wouldn't have been earthed.

Chances of a cable coming into contact with them is slim but still a chance I guess.

Feeling absolutely fine with the blank mcbs

 

[Pat H]

Don't sweat it. Worst case he makes a comment and you discuss it.

 

[DPG]

You're worrying far too much about these blanks! Daz