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Topic Title: Loss of PEN - statistics required please.
Topic Summary: Does anyone have a information on the amount of occurrences per year?
Created On: 20 October 2017 10:06 AM
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 20 October 2017 10:06 AM
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JohnDMcC

Posts: 5
Joined: 20 October 2015

Hi all

New to this forum, but have found it very useful. Have just joined the IET to improve my own knowledge.

I have to do a workshop on various topics and one of them is "the effect of a loss of a PEN conductor"

Whilst the dangers etc are well know and documented i cannot seem to find a breakdown of the amount of occurrences. It would also be great if the statistics were broken down into regions.

Many thanks in advance

John M
 20 October 2017 11:11 AM
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Legh

Posts: 4045
Joined: 17 December 2004

Welcome to the forum
I very much doubt that this information will be readily available to you unless some kindly person sends you an early Christmas present.
Its unlikely that Utility companies will make known their failures on a public forum.
However, you never know there maybe a whistle blower out there....

Legh

-------------------------

http://www.leghrichardson.co.uk

de-avatared
 20 October 2017 12:50 PM
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statter

Posts: 148
Joined: 06 February 2013

Hello, this sort of information would be very helpful and is presumably used anyway by the committee to justify changes and upgrades to the regs. I would try the Energy Networks Association - google their NaFIRS scheme and you will find a contact. http://www.energynetworks.org/...ngineering/nafirs.html Good luck.
 20 October 2017 01:13 PM
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arg

Posts: 152
Joined: 18 March 2015

The HSE should have the info, as it's required to be reported under the ESQCR:

http://www.hse.gov.uk/esqcr/what-must-be-reported.htm

However, I've not seen them publishing it.
 20 October 2017 11:39 PM
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sparkingchip

Posts: 10107
Joined: 18 January 2003

Have a read of the IET electric vehicle charging book.

Andy B.
 21 October 2017 11:22 AM
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statter

Posts: 148
Joined: 06 February 2013

If the HSE have them you can get them using a Freedom of Information request. Its a straightforward process.
 23 October 2017 09:19 AM
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gkenyon

Posts: 4954
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Originally posted by: sparkingchip

Have a read of the IET electric vehicle charging book.



Andy B.
At best, this will only provide a technical perspective from 3-4 years ago - and that may not match current perspective that we saw glimpses of in the 18th Edition DPC.

-------------------------
EUR ING Graham Kenyon CEng MIET TechIOSH
G Kenyon Technology Ltd

Web-Site: www.gkenyontech.com
 23 October 2017 09:23 AM
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JohnDMcC

Posts: 5
Joined: 20 October 2015

Hi all many thanks for your responses, if the information does come my way i will post back here. As long as i am allowed
 27 October 2017 09:30 PM
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UKPN

Posts: 667
Joined: 17 January 2012

"While the dangers are well known"

Dangers? what dangers? does the poster work for the IET? In a correctly installed electrical installation with the required earthed equipotential bonding and a DNO network constructed to the ESQCR regulations every precaution is taken to avoid danger. The distribution companys have over 80 years experience of network design and the word danger is not in our vocabulary.

Regards, UKPN
 29 October 2017 01:09 PM
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AJJewsbury

Posts: 16008
Joined: 13 August 2003

Dangers? what dangers?

Electric shock - as no equipotential zone is ever perfect (e.g. Burnley primary school - "Thirteen children suffer electric shocks and teacher is 'blown through the air") and many electrical installations (and some extraneous-conductive-parts) need to extend beyond the building anyway.

Fire & burns from bonding conductors and other parts having to carry very significant neutral currents when the DNO's CNE fails (see accounts from our own John Peckham) - normal PME bonding sizes only account for diverted N currents in normal service when the CNE is intact, not when they're expected to carry all the N current from one, or several, installations on their own.

Permanent and expensive damage to electrical equipment due to overvoltage on lightly loaded phases (although that's true for any 3-phase system with a broken N regardless of earthing system).

- Andy.
 29 October 2017 03:46 PM
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Zoomup

Posts: 3366
Joined: 20 February 2014

Yes Andy, the Briercliffe Primary School in Burnley apparently had a lost neutral and the fences and other metal parts became live. http://www.bbc.co.uk/news/uk-e...d-lancashire-27925511

Z.
 29 October 2017 06:17 PM
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sparkingchip

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 29 October 2017 06:29 PM
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sparkingchip

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Originally posted by: Zoomup

Yes Andy, the Briercliffe Primary School in Burnley apparently had a lost neutral and the fences and other metal parts became live. http://www.bbc.co.uk/news/uk-e...ashire-27925511



Z.


An electrically live fence suggests PME has been exported outside of the equipotential zone.

It also begs the question if the metal fence posts provided sufficient earth electrodes to prevent a dangerous voltage being present on the fence.

Andy B.
 29 October 2017 10:54 PM
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mapj1

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well, presuming they had cameras or lights on the fence posts that used the building earth. Clearly a run of fence posts and the steel frame of a pre-fab wwbuilding all in parallel are not enough to hold down the neutral to any sensible level.

-------------------------
regards Mike
 29 October 2017 11:12 PM
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sparkingchip

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Originally posted by: mapj1

well, presuming they had cameras or lights on the fence posts that used the building earth. Clearly a run of fence posts and the steel frame of a pre-fab wwbuilding all in parallel are not enough to hold down the neutral to any sensible level.


No one died as a result of the electric shocks they received, does that meet the definition of preventing dangerous voltage levels?

Andy B.
 30 October 2017 11:47 AM
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gkenyon

Posts: 4954
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Originally posted by: sparkingchip

Originally posted by: mapj1



well, presuming they had cameras or lights on the fence posts that used the building earth. Clearly a run of fence posts and the steel frame of a pre-fab wwbuilding all in parallel are not enough to hold down the neutral to any sensible level.




No one died as a result of the electric shocks they received, does that meet the definition of preventing dangerous voltage levels?



Andy B.
Perhaps not ... "danger" in the Electricity at Work Regulations means "risk of injury", and further "injury" is defined in the same legislation as "death or personal injury from electric shock, electric burn, electrical explosion or arcing, or from fire or explosion initiated by electrical energy, where any such death or injury is associated with the generation, provision, transmission, transformation, rectification, conversion, conduction, distribution, control, storage, measurement or use of electrical energy"

So, if they had a "level of perception" shock (this could have led to, for example personal injury as a result of secondary effects) ... the voltage level was perhaps "dangerous" by this definition?

Just a thought ...

-------------------------
EUR ING Graham Kenyon CEng MIET TechIOSH
G Kenyon Technology Ltd

Web-Site: www.gkenyontech.com
 30 October 2017 01:39 PM
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AJJewsbury

Posts: 16008
Joined: 13 August 2003

An electrically live fence suggests PME has been exported outside of the equipotential zone.

Although another possibility is that the fence was earthy, just something else they were already touching was live (e.g. part of the building) - most people seem to assume that if they feel a shock when they touch something then it must be that something that's live - rather than realising that it's just completing the circuit...
- Andy.
 31 October 2017 08:30 AM
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Zoomup

Posts: 3366
Joined: 20 February 2014

"A school in Lancashire where 13 children and a teacher received electric shocks after a power cut in the area is to reopen.
Briercliffe County Primary School in Burnley was evacuated on Wednesday after the shocks, understood to be from live metal items including door handles."

Does this BBC report give any clue?

Z.
 31 October 2017 12:40 PM
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alancapon

Posts: 6919
Joined: 27 December 2005

No, the BBC report gives no details of what the fault was.

Regards,

Alan.
 31 October 2017 02:04 PM
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AJJewsbury

Posts: 16008
Joined: 13 August 2003

No, the BBC report gives no details of what the fault was.

Although the complete absence of any comments from the IET, 'Electrical Safety First' et al, might be taken as suggesting it wasn't an installation side problem?

- Andy.
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