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Topic Title: NEW REQUIREMENT FOR NEW SUPPLY FROM UKPN
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Created On: 10 December 2013 10:46 PM
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 10 December 2013 10:46 PM
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John Peckham

Posts: 7459
Joined: 23 April 2005

One of my network of contractors called me this evening to ask my opinion on a requirement being imposed on him by UKPN before they will connect a new supply.

This is a in a conversion of a building to flats. he has erected a Ryfield board as usual to supply each of the new flats. The DNO have provided a new head, I think either 200A or 400A. The man came to connect up but refused as he wants to see a main switch between the head and the Ryfiled board. The contractor has not allowed for the cost for this and even worse the enclosure constructed to house the supply equipment and metering is not big enough for a big switch/isolator.

I have advised him to get UKPN to confirm this in writing and also ask for the policy document that requires this. I have seen or been involved with quite a few new block of flats and UKPN seem to make it up as they go along as to where they want the head, meters, distribution circuits, red heads/solid links, switch fuses at the origin or distribution circuits supplied direct off the Ryfield etc etc.

Is this a new policy or a personal preference for the person who came to site? Has anyone else had a similar requirement imposed upon them?

It seems a good idea to me as a benefit for fire fighters to have a single easy means of isolation but is it a new policy?

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John Peckham

http://www.astutetechnicalservices.co.uk/
 11 December 2013 09:22 AM
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Parsley

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Joined: 04 November 2004

John

Take a look at this link page 17 and 18.

http://library.ukpowernetworks...ccupied+buildings.pdf

Regards
 11 December 2013 12:12 PM
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OMS

Posts: 19666
Joined: 23 March 2004

The contractor is de facto building network operator (BNO) in this respect - difficult to see how him omitting a main switch or circuit breaker is compliant with BS 7671 and thus the requirements of the DNO.

Regards

OMS

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Failure is always an option
 11 December 2013 02:02 PM
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Jobbo

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John

UKPN and the energy provider always provide a scope of works and a drawings, that you generally have to stick 100% too, otherwise the guy coming to connect up will make any excuse to walk away. Sometime they even walk away when you have done everything to the letter. Get your friend to have a look at the information provided and go from there.

P.S What happened to this years Xmas drink?

Regards

Jobbo
 11 December 2013 05:13 PM
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jcm256

Posts: 1866
Joined: 01 April 2006

Perhaps they spied one or both of the following scenarios, in which you have to abide by the regulations (what regulation was that in BS7671) don't' have the current regulation book to hand now at the moment.


Protection against overload
If the neutral conductor is correctly sized (including harmonics), no specific protection of the neutral conductor is required because it is protected by the phase protection.
However, in practice, if the c.s.a. of the neutral conductor is lower than the phase c.s.a, a neutral overload protection must be installed.

Protection against short-circuit
If the c.s.a. of the neutral conductor is lower than the c.s.a. of the phase conductor, the neutral conductor must be protected against short-circuit.
If the c.s.a. of the neutral conductor is equal or greater than the c.s.a. of the phase conductor, no specific protection of the neutral conductor is required because it is protected by the phase protection.


Nothing to do with the question but also read:

In the last decade very few people would have expected the phenomenal growth in non linear loads and
resulting harmonics. Low voltage networks incorporating half rated neutrals had many loads
incorporating hundreds of pcs, variable speed drives and UPS.
These systems are now becoming dangerously close to overheating,
particularly on the neutral conductor.
The problem with harmonic profiles is trying to predict how these will
increase over the years.



It is not as if UKPN a China (Hong Kong) owner are making any money asking for additional protection. so it must be on technical grounds.

Edited: 11 December 2013 at 05:38 PM by jcm256
 11 December 2013 05:35 PM
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UKPN

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"seem to make it up as they go along"

"make any excuse to walk away"

its boring-about time certain posters on here moved into the 21st century-these types of supplies have been around for ages-

Regards
 11 December 2013 07:05 PM
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peteTLM

Posts: 3152
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I have never seen a mainswitch between the head and the 1st ryefield board.

UKPN- poster- all we ask is consistency, and as a company, you certainly dont provide that.

I have seen new installs in flats (all ukpn- edf areas) recently with and without short circuit protection for the SWA submain. Where it is provided, 1 job had another ryefield board with multiway input (thus providing protection but not breaking the neutral in anyway), another individual switchfuses, and others no protection at all.

Its about time you lot looked after your earthing provisions on TNS supplies as well mate, rather than just treating it as a cash cow 'oh, you have to pay for TNCS'.

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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
 11 December 2013 07:15 PM
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OMS

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I have never seen a mainswitch between the head and the 1st ryefield board


Historically, no

but:

the risers and laterals were always under the control of the DNO (or former area boards).

As the DNO's now can't be ar****d to look after them, they have quietly pushed that over to the Building Network Operator.

As part of this, the DNO now want (usually) a sealed, main switch, circuit breaker or switchfuse seperating thier cut out from the traditional ryfields unit and subsequent SNE distribution to the red heads, meters and individual flat consumer units.

I'd bet if someone checked UKPN's manual on this, it has a main switch shown clearly

It's the classic problem of "but we've always done it that way, mate"

Regards

OMS

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Failure is always an option
 11 December 2013 07:43 PM
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slittle

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I've got a project on the go at the moment which will end up with a Ryefield.

It was made very clear when the project designer visited site that they would provide a cutout from which we needed to install a mainswitch and then into whatever distribution we deemed necessary.

I think it all changed with the guidelines that came out last year.


Jobbo, I think Christmas has crept up on us a bit quick this year, perhaps we'll have to do a welcome 2014 drink instead

Stu
 11 December 2013 08:14 PM
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Jobbo

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I know what you mean stu, been a manic few months. A new year meet, sounds like a plan.
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