IET
Decrease font size
Increase font size
Topic Title: EMMA SHAW CASE
Topic Summary: Result of the Court case
Created On: 31 March 2014 04:35 PM
Status: Read Only
Linear : Threading : Single : Branch
 EMMA SHAW CASE   - John Peckham - 31 March 2014 04:35 PM  
 EMMA SHAW CASE   - John Peckham - 31 March 2014 05:19 PM  
 EMMA SHAW CASE   - OMS - 31 March 2014 05:23 PM  
 EMMA SHAW CASE   - AJJewsbury - 31 March 2014 05:26 PM  
 EMMA SHAW CASE   - John Peckham - 31 March 2014 05:30 PM  
 EMMA SHAW CASE   - impvan - 31 March 2014 05:31 PM  
 EMMA SHAW CASE   - rocknroll - 31 March 2014 05:46 PM  
 EMMA SHAW CASE   - perspicacious - 31 March 2014 06:02 PM  
 EMMA SHAW CASE   - jcm256 - 31 March 2014 06:03 PM  
 EMMA SHAW CASE   - aligarjon - 31 March 2014 08:21 PM  
 EMMA SHAW CASE   - jcm256 - 31 March 2014 08:53 PM  
 EMMA SHAW CASE   - aligarjon - 31 March 2014 10:26 PM  
 EMMA SHAW CASE   - sparkingchip - 31 March 2014 11:54 PM  
 EMMA SHAW CASE   - antric2 - 01 April 2014 12:40 AM  
 EMMA SHAW CASE   - Zoro - 01 April 2014 09:23 AM  
 EMMA SHAW CASE   - davezawadi - 01 April 2014 10:57 AM  
 EMMA SHAW CASE   - OMS - 01 April 2014 11:17 AM  
 EMMA SHAW CASE   - mapj1 - 01 April 2014 12:41 AM  
 EMMA SHAW CASE   - antric2 - 01 April 2014 12:46 AM  
 EMMA SHAW CASE   - aligarjon - 01 April 2014 08:07 AM  
 EMMA SHAW CASE   - AJJewsbury - 01 April 2014 09:15 AM  
 EMMA SHAW CASE   - weirdbeard - 01 April 2014 03:27 PM  
 EMMA SHAW CASE   - AJJewsbury - 01 April 2014 11:15 AM  
 EMMA SHAW CASE   - AJJewsbury - 01 April 2014 11:36 AM  
 EMMA SHAW CASE   - OMS - 01 April 2014 12:23 PM  
 EMMA SHAW CASE   - phantom9 - 01 April 2014 01:14 PM  
 EMMA SHAW CASE   - OMS - 01 April 2014 01:43 PM  
 EMMA SHAW CASE   - AJJewsbury - 01 April 2014 01:22 PM  
 EMMA SHAW CASE   - davezawadi - 01 April 2014 02:14 PM  
 EMMA SHAW CASE   - ennel - 01 April 2014 07:07 PM  
 EMMA SHAW CASE   - Zoro - 02 April 2014 10:20 AM  
 EMMA SHAW CASE   - weirdbeard - 01 April 2014 03:21 PM  
 EMMA SHAW CASE   - OMS - 01 April 2014 03:28 PM  
 EMMA SHAW CASE   - AJJewsbury - 01 April 2014 03:15 PM  
 EMMA SHAW CASE   - AJJewsbury - 01 April 2014 03:27 PM  
 EMMA SHAW CASE   - John Peckham - 01 April 2014 03:36 PM  
 EMMA SHAW CASE   - phantom9 - 02 April 2014 09:05 AM  
 EMMA SHAW CASE   - phantom9 - 02 April 2014 09:10 AM  
 EMMA SHAW CASE   - OMS - 02 April 2014 10:16 AM  
 EMMA SHAW CASE   - sparkingchip - 02 April 2014 12:00 PM  
 EMMA SHAW CASE   - phantom9 - 02 April 2014 06:57 PM  
 EMMA SHAW CASE   - AJJewsbury - 02 April 2014 09:15 AM  
 EMMA SHAW CASE   - phantom9 - 02 April 2014 09:21 AM  
 EMMA SHAW CASE   - AJJewsbury - 02 April 2014 09:38 AM  
 EMMA SHAW CASE   - mapj1 - 02 April 2014 10:26 AM  
 EMMA SHAW CASE   - OMS - 02 April 2014 12:06 PM  
 EMMA SHAW CASE   - AJJewsbury - 02 April 2014 12:14 PM  
 EMMA SHAW CASE   - mapj1 - 02 April 2014 01:20 PM  
 EMMA SHAW CASE   - OMS - 02 April 2014 01:50 PM  
 EMMA SHAW CASE   - AJJewsbury - 02 April 2014 03:04 PM  
 EMMA SHAW CASE   - OMS - 02 April 2014 04:13 PM  
 EMMA SHAW CASE   - GeoffBlackwell - 02 April 2014 04:22 PM  
 EMMA SHAW CASE   - rocknroll - 02 April 2014 04:26 PM  
 EMMA SHAW CASE   - AJJewsbury - 02 April 2014 05:50 PM  
 EMMA SHAW CASE   - phantom9 - 02 April 2014 06:36 PM  
 EMMA SHAW CASE   - Zuiko - 02 April 2014 07:02 PM  
 EMMA SHAW CASE   - geoffsd - 02 April 2014 07:33 PM  
 EMMA SHAW CASE   - OMS - 02 April 2014 08:24 PM  
 EMMA SHAW CASE   - phantom9 - 02 April 2014 11:38 PM  
 EMMA SHAW CASE   - mawry - 03 April 2014 02:39 PM  
 EMMA SHAW CASE   - briandoherty - 06 April 2014 06:09 PM  
 EMMA SHAW CASE   - Zs - 07 April 2014 07:27 PM  
 EMMA SHAW CASE   - mawry - 08 April 2014 11:13 AM  
 EMMA SHAW CASE   - mikejumper - 08 April 2014 07:46 PM  
 EMMA SHAW CASE   - napitprofessional - 09 April 2014 12:06 AM  
 EMMA SHAW CASE   - Zoro - 09 April 2014 10:50 AM  
 EMMA SHAW CASE   - napitprofessional - 09 April 2014 02:01 PM  
 EMMA SHAW CASE   - AJJewsbury - 02 April 2014 08:23 PM  
 EMMA SHAW CASE   - Parsley - 02 April 2014 10:30 PM  
 EMMA SHAW CASE   - electricman - 02 April 2014 11:06 PM  
 EMMA SHAW CASE   - ericmark - 03 April 2014 02:37 PM  
 EMMA SHAW CASE   - Zoro - 04 April 2014 09:20 AM  
 EMMA SHAW CASE   - John Peckham - 06 April 2014 03:53 PM  
 EMMA SHAW CASE   - electricman - 08 April 2014 11:19 PM  
 EMMA SHAW CASE   - AJJewsbury - 08 April 2014 11:23 PM  
 EMMA SHAW CASE   - mikejumper - 09 April 2014 04:42 PM  
 EMMA SHAW CASE   - OMS - 09 April 2014 05:14 PM  
 EMMA SHAW CASE   - psychicwarrior - 10 April 2014 08:56 AM  
 EMMA SHAW CASE   - napitprofessional - 11 April 2014 05:54 PM  
 EMMA SHAW CASE   - davezawadi - 12 April 2014 11:46 AM  
 EMMA SHAW CASE   - sparkingchip - 12 April 2014 12:33 PM  
 EMMA SHAW CASE   - John Peckham - 12 April 2014 01:21 PM  
 EMMA SHAW CASE   - weirdbeard - 12 April 2014 06:28 PM  
 EMMA SHAW CASE   - sparkingchip - 12 April 2014 06:51 PM  
 EMMA SHAW CASE   - weirdbeard - 12 April 2014 08:11 PM  
 EMMA SHAW CASE   - sparkingchip - 12 April 2014 10:57 PM  
 EMMA SHAW CASE   - phantom9 - 12 April 2014 04:02 PM  
 EMMA SHAW CASE   - Grobbyman - 12 April 2014 05:44 PM  
 EMMA SHAW CASE   - Zoro - 12 April 2014 06:11 PM  
 EMMA SHAW CASE   - Fm - 12 April 2014 11:26 PM  
 EMMA SHAW CASE   - sparkingchip - 12 April 2014 11:37 PM  
 EMMA SHAW CASE   - Fm - 12 April 2014 11:40 PM  
 EMMA SHAW CASE   - sparkingchip - 13 April 2014 12:04 AM  
 EMMA SHAW CASE   - phantom9 - 13 April 2014 09:25 AM  
 EMMA SHAW CASE   - OMS - 14 April 2014 10:13 AM  
 EMMA SHAW CASE   - potential - 14 April 2014 10:32 AM  
Search Topic Search Topic
Topic Tools Topic Tools
View similar topics View similar topics
View topic in raw text format. Print this topic.
 31 March 2014 04:35 PM
User is offline View Users Profile Print this message



John Peckham

Posts: 9097
Joined: 23 April 2005

The Mr Hoult the NICEIC QS was found guilty last week of the charges relating to Section 7 of the Health and Safety at Work Act.

Mr Tomkins the electricians mate was found not guilty today of charges under section 7 of the Health and Safety at Work Act by a majority verdict of the jury.

-------------------------
John Peckham

http://www.astutetechnicalservices.co.uk/
 31 March 2014 05:19 PM
User is offline View Users Profile Print this message



John Peckham

Posts: 9097
Joined: 23 April 2005

The case relates to the Death of 22 year old Emma Shaw who was the occupant with her 18 child month of a rented 1st floor flat in West Bromwich in December 2007.

The flat was one of new 42 flats that had electrical installation carried out by Anchor Building and Electrical services an NICEIC Approved Contractor in 2006.

The internal walls were constructed of "C" section metal studwork covered with plasterboard. A hall cupboard contained a pressurised water boiler above which was mounted a consumer unit supplied from a distribution circuit from a switch fuse in a an riser cupboard external to the flat. The means of earthing was TN-C-S. None of the circuits in the consumer unit were RCD protected. Circuit No. 3 supplied one of the immersion heaters in the boiler.

The electrical installation had been 1st fixed the plaster board fitted to the metal studding before the installation was 2nd fixed. Circuit 3 supplied a 20A double pole switch at high level which supplied a cable outlet at low level, this in turn supplied the water heater in flex.

The cable to the flex outlet was longer than it should be and when the plasterboard was installed the cable was trapped between the plasterboard and the stud-work. In addition a plasterboard screw passed through the cable clipping the Line and CPC conductors and in to the studwork.

The installation had been energised without any testing and the fault current had blown away part of the screw and CPC. This was verified by forensic examination at the HSE laboratories. This left a high resistance fault from the line conductor to the metal studwork.

18 months later the stat. on the water heater failed and the cylinder over pressurised and the safety valve operated and the safety valve operated and discharged in to a tun dish. The plastic waste pipe from the tun dish had parted because it was not glued and the water spilled on to the floor soaking the carpet. The water soaked under the foot of the wall and in to contact with the live studwork.

Miss Shaw was mopping up the water and had texted her partner to come home telling him the hall was flooded and the "electricity was sparking". he partner tetxed back to say to turn off the water stop cock sited in the same cupboard as the boiler.

Later she was found kneeling in the cupboard slumped forward and apparently lifeless. Subsequent examination and a Post Mortum determined that she was kneeling in the charged water and received a fatal shock when she touched the earthed stop valve.

West Midlands Police, the ambulance service and the fire service attended the scene. The police commenced an investigation for a suspicious death.

The police later arrested both the QS Hoult and Tomkins the electricians mate and they were interviewed under caution. Tomkins had signed an Electrical Installation Certificate as the Inspector. He admitted he was not qualified or competent to do so. He said he had been taken to the flat by the electrical site foreman and told to do ring continuity and loop impedance testing.He said when he got to the flat the installation was already energised. He did no other inspection and testing. He said that in the site hut they had sat around the table with the site foreman and was told the other tests had been done and he was told what to write on the test certificate.

This EIC was submitted to Anchors offices where a type written certificate was produced. The type written version had differences to Tomkins hand written version. The typed version had "P/P C Tomkins" in the single signature box for design. construction and inspection. Tomkins said in court he had not seen the typed form and he would not have consented to his signature being used. Mr Hoult the QS said that he just checked the figures on the form and signed it as the QS. he did not go to site and was not involved in the testing and inspection. Mr Hoult had known Tomkins for many years and it was alleged he knew about Tomkins status as a mate and his lack of qualifications.

Those are the brief facts that will no doubt generate a lot of questions. I have some of the detail from the expert witnesses, the police and others. The HSE produced an excellent DVD of a computer generated simulation of the accident shown in court to explain the circumstances and the consequences of the events in non-technical language.

-------------------------
John Peckham

http://www.astutetechnicalservices.co.uk/
 31 March 2014 05:23 PM
User is offline View Users Profile Print this message



OMS

Posts: 22864
Joined: 23 March 2004

Interesting - particularly in light of the recent Parliamentary committee dealing with Part P and some of the submissions and conclusions drawn from it.

Do we not now have a precendent case that suggets the installer does still indeed have the protection of the vicarious liability afforded by the employer ?

Or conversely, that employers need to employ competent people - which is always the case.

Regards

OMS

-------------------------
Let the wind blow you, across a big floor.
 31 March 2014 05:26 PM
User is offline View Users Profile Print this message



AJJewsbury

Posts: 17795
Joined: 13 August 2003

Thanks John. Very interesting.

- Andy.
 31 March 2014 05:30 PM
User is offline View Users Profile Print this message



John Peckham

Posts: 9097
Joined: 23 April 2005

Mr Hoult was charged with Failing to supervise, failing to take proper care in the reasonable recording of the test results contrary to Section 7 of the Health and Safety at Work Act.

I feel sure that I am not the only person who is not surprised that the the results for the inspecting and testing were completed as a group exercise sitting around the mess table in the site hut?

-------------------------
John Peckham

http://www.astutetechnicalservices.co.uk/
 31 March 2014 05:31 PM
User is offline View Users Profile Print this message



impvan

Posts: 922
Joined: 07 September 2005

And in addition to the electrical failings, what about the pipework from the safety valve?

I understood this was supposed to only ever be in metal?
 31 March 2014 05:46 PM
User is offline View Users Profile Print this message



rocknroll

Posts: 9677
Joined: 03 October 2005

Section 7

General duties of employees at work.

It shall be the duty of every employee while at work -

(a) to take reasonable care for the health and safety of himself and of other persons who may be affected by his acts or omissions at work;

and .

(b) as regards any duty or requirement imposed on his employer or any other person by or under any of the relevant statutory provisions, to co-operate with him so far as is necessary to enable that duty or requirement to be performed or complied with.

Sections 7 to 9 HSWA 1974.

These offences are punishable on conviction in the magistrates court by a fine up to £5,000, and on conviction in the Crown Court by an unlimited fine.

However, where a person is convicted in the Crown Court of any of the above offences that consists of a breach of licence requirements or certain provisions relating to explosives, the maximum penalty is two years' imprisonment and/or an unlimited fine.

Whilst the costs/fines look severe on paper you have to remember that where individuals are concerned they are subject to means testing which means what they only have to pay a contribution of up to 7% the rest comes from a social fund, the purpose of this is so people do not suffer economic or social hardship, like losing their jobs and material assets such as housing etc, just basic human rights.

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: 31 March 2014 at 06:00 PM by rocknroll
 31 March 2014 06:02 PM
User is offline View Users Profile Print this message



perspicacious

Posts: 8055
Joined: 18 April 2006

 31 March 2014 06:03 PM
User is offline View Users Profile Print this message



jcm256

Posts: 2327
Joined: 01 April 2006

It is easy to overlook some trivial defect when compiling a report but ticking a box that a RCD is present when none fitted is deplorable.

http://www.expressandstar.com/...electrocution-at-flat/
 31 March 2014 08:21 PM
User is offline View Users Profile Print this message



aligarjon

Posts: 4053
Joined: 09 September 2005

Originally posted by: jcm256

It is easy to overlook some trivial defect when compiling a report but ticking a box that a RCD is present when none fitted is deplorable.



http://www.expressandstar.com/...electrocution-at-flat/




why was the lack of rcd a defect. in 2007 i doubt anyone fitted rcd's to imersion circuits.

Gary

-------------------------
Specialised Subject. The Bleedin Obvious. John Cleese
 31 March 2014 08:53 PM
User is offline View Users Profile Print this message



jcm256

Posts: 2327
Joined: 01 April 2006

Yes you could be right, but the fact ticking a box that there was one when in fact there was not, was it a guess without checking we don't know.
 31 March 2014 10:26 PM
User is offline View Users Profile Print this message



aligarjon

Posts: 4053
Joined: 09 September 2005

yes it sounds like he didn't even go into the property. i suspect it goes on all the time.

Gary

-------------------------
Specialised Subject. The Bleedin Obvious. John Cleese
 31 March 2014 11:54 PM
User is offline View Users Profile Print this message



sparkingchip

Posts: 11682
Joined: 18 January 2003

 01 April 2014 12:40 AM
User is offline View Users Profile Print this message



antric2

Posts: 1267
Joined: 20 October 2006

With ref; to the RCD box being ticked for a non present RCD,
I upgraded a consumer unit some 3 or 4 years ago at a house just after a bathroom refit that had had a small con unit fitted with no RCD protection.
The cert had ticked the RCD present box but upon my testing was getting >310ms.
Where was the RCD in question I thought that was not operating correctly\gone faulty.
Phoned the electrician (Niceic Approved) who issued cert to ask where RCD was."It is an RCBO "he said...."No it isnt" I replied at which he replied that he had told his collegue to order and fit an RCBO .
When I asked him to explain how and why the x1 and x5 test had been recorded at 18ms he replied that all Hagar RCBO,s were 18ms trip time and that was that.....I was quite surprised at his audacity and flippant manner.

The customer was fuming,complained to the bathroom company....no joy....customer complained to NICEIC and because I had done the consumer unit and integrated the bathroom circuit onto my new RCD board would not take action.

This was one the installer had been caught out with but how many more guestimated certs of his are out there!!! NIC were not interested about that.
Regards
Antric
 01 April 2014 09:23 AM
User is offline View Users Profile Print this message



Zoro

Posts: 300
Joined: 31 July 2011

Originally posted by: antric2

With ref; to the RCD box being ticked for a non present RCD,

I upgraded a consumer unit some 3 or 4 years ago at a house just after a bathroom refit that had had a small con unit fitted with no RCD protection.

The cert had ticked the RCD present box but upon my testing was getting >310ms.

Where was the RCD in question I thought that was not operating correctly\gone faulty.

Phoned the electrician (Niceic Approved) who issued cert to ask where RCD was."It is an RCBO "he said...."No it isnt" I replied at which he replied that he had told his collegue to order and fit an RCBO .

When I asked him to explain how and why the x1 and x5 test had been recorded at 18ms he replied that all Hagar RCBO,s were 18ms trip time and that was that.....I was quite surprised at his audacity and flippant manner.

The customer was fuming,complained to the bathroom company....no joy....customer complained to NICEIC and because I had done the consumer unit and integrated the bathroom circuit onto my new RCD board would not take action.


This was one the installer had been caught out with but how many more guestimated certs of his are out there!!! NIC were not interested about that.

Regards
Antric


The NICEIC and their owners the Electrical Safety Council are never interested in safety issues, when another of their members are found doing non compliant and dangerous work.

The list of cases where the NICEIC/ESC turn there backs and walk away grows day by day, so much for the propaganda about being a safety organisation.

Even in this case with the sad death of Emma Shaw (22), the NICEIC/ESC walked away, I don't know how they can pretend any more to have any interest in the safety of the public.

With the slow collapse of the Part P Schemes structure, you can see why it is happening, when it is based on the standards and policies of the NICEIC.

With the Trade having given the Schemes aver £160 million over the last nine years we are no better off, it should be scrapped.

.
 01 April 2014 10:57 AM
User is offline View Users Profile Print this message



davezawadi

Posts: 4259
Joined: 26 June 2002

This case has another interesting point which is worth considerng.
The use of metal studwork obviously contributed to the outcome, so should we consider if this is actually an exposed conductive part, and therefore should have been bonded to earth. It is very difficult to tell if cables are trapped when boarding this studwork as it simply distorts allowing the boards to fit flat, and the long and pointed screws are very capable of penetrating almost anything.

-------------------------
David
BSc CEng MIET
 01 April 2014 11:17 AM
User is offline View Users Profile Print this message



OMS

Posts: 22864
Joined: 23 March 2004

Personally I wouldn't want to see an approach that tries to effectively earth every metallic component within the wall structure - madness.

I'm old enough (just) to have worked on a number of system build schools that had colour coated metallic partioning systems. This was the 15th edition and everyone wanted to earth and bond everything - it was total madness. I can remember sitting there actually showing bonding points to the panels on drawings because the senior engineer had decreed it -

Hindsight I appreciate, but we now have Reg 522.6.103 and we also have RCD protection to meet the requirements of additional protection - a million little curly green and yellow pigtails isn't going to be helpful in my opinion. To be a bit regimentally insane about it, how would you inspect them post construction as a simple reson for why no to do it

If the installer actually knows what he is doing (and gives a *****) then it's difficult to see how cables are routinely being trapped between boards and studs - basically there shouldn't be enough "slack" for that to happen - and equally, penetrating the C stud and hitting the cable shouldn't happen - as the cables shouldn't be using the stud as containment.

Regards

OMS

-------------------------
Let the wind blow you, across a big floor.
 01 April 2014 12:41 AM
User is offline View Users Profile Print this message



mapj1

Posts: 12039
Joined: 22 July 2004

It is of course desperately sad for all involved, but also mercifully rare that a fault like this actually leads to fatality, as a number of things have to be badly wrong together. I this case the screw, the water and the fact she was in the water when, we must presume, she reached for the earthed plumbing.
We will not know how many wires out there are spiked by screws and nails, but luckily don't lead to ill effect, though we may guess its a good few from the number of times a wire is found that was clearly damaged ages before discovery - well I've found a few, and I've even drilled a cable I put in myself, and felt suitably foolish afterwards.
I also doubt that all cases will be found by the current testing methods, though actually doing them can only be a help. Certainly the presence of just a live screw alone, not touching E is unlikely to be spotted if the wall is dry, maybe a large area of foil backed board could be detected by measuring L-E versus N-E capacitance imbalance, but I can't see that getting added onto the list of things to be tested any time soon.
An RCD would have helped, in this case at least, so we can expect these sort of headlines to gradually become less common if we continue to encourage RCD use.
How would we be reacting if all the testing and paper work had been completed correctly, and the accident had still occurred I wonder ? (assuming the insulation had been L+N to E >100meg = "test pass" on switch-on day?)

regards

Mike

-------------------------
regards Mike
 01 April 2014 12:46 AM
User is offline View Users Profile Print this message



antric2

Posts: 1267
Joined: 20 October 2006

Another thing; I think the safety council should run an awareness campaign to highlight the need to regularly test RCD function with the test button and also to highlight the safety advantage of having RCDs installed in their home.
Regards
Antric
PS; I am not an RCD salesman...honest
 01 April 2014 08:07 AM
User is offline View Users Profile Print this message



aligarjon

Posts: 4053
Joined: 09 September 2005

i suspect that if the screw had just nicked the live and into the frame the result would have been the same with the installation passing all tests and livened up. or could actually happen on an existing installation that is already powered up if screws are fitted and the cables aren't back properly, which lets face it is possible with the way they stuff insulation into the voids these days.

Gary

-------------------------
Specialised Subject. The Bleedin Obvious. John Cleese
 01 April 2014 09:15 AM
User is offline View Users Profile Print this message



AJJewsbury

Posts: 17795
Joined: 13 August 2003

The installation had been energised without any testing and the fault current had blown away part of the screw and CPC. This was verified by forensic examination at the HSE laboratories. This left a high resistance fault from the line conductor to the metal studwork.

Interesting that it "blow away" (vaporized?) part of the c.p.c. before the MCB opened - given the requirements of section 543 would that have been expected? If the c.p.c. had remained intact in this case, it would seem that it would have been impossible to reset the MCB and the fault would have been apparent.

Perhaps we should question the idea of faults of negligible impedance?

- Andy.
 01 April 2014 03:27 PM
User is offline View Users Profile Print this message



weirdbeard

Posts: 3116
Joined: 26 September 2011

Originally posted by: AJJewsbury

Interesting that it "blow away" (vaporized?) part of the c.p.c. before the MCB opened - given the requirements of section 543 would that have been expected? If the c.p.c. had remained intact in this case, it would seem that it would have been impossible to reset the MCB and the fault would have been apparent.


.


Just conjecture on my part, but when they energised the installation the first time, they might not have switched on the immersion switch - then the immersion was connected and switched on by a plumber, who could have switched up the breaker a couple of times until it held, leading to the burning away of the cpc?

Easy (repeated) user resetting - one of the downsides of MCBs? Might not have happened if it was a rewirable fuse?

-------------------------
:beer)
 01 April 2014 11:15 AM
User is offline View Users Profile Print this message



AJJewsbury

Posts: 17795
Joined: 13 August 2003

The use of metal studwork obviously contributed to the outcome, so should we consider if this is actually an exposed conductive part, and therefore should have been bonded to earth.

earthed?

Probably difficult to achieve in practice - perhaps a better alternative would be to use a wiring system that included earthed metal between the live conductors and the rest of the world - BS 8436 cables perhaps (assuming you don't want the expense of pyro). That would guard against the screw just hitting L alone without shorting to c.p.c too.

I believe the Americans have a preference for flexible steel conduit in these situations - it's a pity our regs prohibit it even though there'd be no vibration in such cases. The French tend to use singles in flexible conduit for concealed domestic wiring too - it must make alterations so much easier - but they tend to use the plastic variety.

- Andy.
 01 April 2014 11:36 AM
User is offline View Users Profile Print this message



AJJewsbury

Posts: 17795
Joined: 13 August 2003

penetrating the C stud and hitting the cable shouldn't happen - as the cables shouldn't be using the stud as containment.

Although the cables will have to pass through a C stud at some point - top, bottom, left or right; and it's not unknown to find a rogue over-length screw in a box of plasterboard screws.

- Andy.
 01 April 2014 12:23 PM
User is offline View Users Profile Print this message



OMS

Posts: 22864
Joined: 23 March 2004

Isn't that why we have defined routing zones, Andy ?

Basically, this is a workmanship issue - good workmanship and proper materials should minimise the potential for trapping/spiking the cable - coupled with reasonable testing, the risk has to be very low of this being a repeatable incident - I suspct there won't be another for quite a while.

and it's not unknown to find a rogue over-length screw in a box of plasterboard screws.


True - but not that many - and you would expect a good boardera nd tacker to sling it out - particularly if using magazine feed screw fixers


Regards

OMS

-------------------------
Let the wind blow you, across a big floor.
 01 April 2014 01:14 PM
User is offline View Users Profile Print this message



phantom9

Posts: 1757
Joined: 16 December 2002

Just wanted to throw in a curved ball.

If the incoming water supply pipe was MDPE and the water pipes within the flat were metal, the bonded pipe had earth potential introduced to it. If the pipework had not been bonded could she have survived? The fatal shock was received, was it not, when she knelt down to turn the water stopcock off. This apparently completed the fault circuit and she died. If the fault path had been prevented from completing could she have survived?
 01 April 2014 01:43 PM
User is offline View Users Profile Print this message



OMS

Posts: 22864
Joined: 23 March 2004

Originally posted by: phantom9

Just wanted to throw in a curved ball.



If the incoming water supply pipe was MDPE and the water pipes within the flat were metal, the bonded pipe had earth potential introduced to it. If the pipework had not been bonded could she have survived? The fatal shock was received, was it not, when she knelt down to turn the water stopcock off. This apparently completed the fault circuit and she died. If the fault path had been prevented from completing could she have survived?


It's not just the bonding - and connection via the cylinder heaters or boiler connection or electric shower would make the pipe earthy, even if it wasn't extraneous and thus not bonded.

Regards

OMS

-------------------------
Let the wind blow you, across a big floor.
 01 April 2014 01:22 PM
User is offline View Users Profile Print this message



AJJewsbury

Posts: 17795
Joined: 13 August 2003

If the incoming water supply pipe was MDPE and the water pipes within the flat were metal, the bonded pipe had earth potential introduced to it. If the pipework had not been bonded could she have survived? The fatal shock was received, was it not, when she knelt down to turn the water stopcock off. This apparently completed the fault circuit and she died. If the fault path had been prevented from completing could she have survived?

I has similar thoughts - but presumed that since there was an earth path from the stopcock then the internal plumbing must have been metallic - hence it would have had a connection to earth via the immersion c.p.c. - so omitting bonding wouldn't have helped in this case. (Unless it was a brass stopcock in an otherwise all plastic system and some 15th Ed reject had bonded the stopcock!)

- Andy.
 01 April 2014 02:14 PM
User is offline View Users Profile Print this message



davezawadi

Posts: 4259
Joined: 26 June 2002

I agree with you OMS about earthing everything in sight, but as I think there was probably very little possibility of detecting this fault once the power was applied, we have an impasse. You could say RCD everything, but that is not the answer because this is not a case where additional protection is indicated. It is a basic workmanship issue true, but any wiring inside this kind of partition is in danger from the construction screws even if it is in the "safe zones". As wiring inside stud walls is rarely fixed, at least in my experience, the zones are not very relevant, and they are bound to have fixing screws anyway.

However the discussion has moved away from what I consider to be the important matter, that is the practices of supposedly "approved" contractors. This case (and many many less serious ones, in outcome at least) show that the QS system is fatally flawed in that it is totally open to abuse and fraud. The unqualified tester appears to be used in flagrant breach of the EAWR by his employer and supervisor. The QS may have been under pressure to issue certs by the same employer. What has happened to the employer? Someone suggested he got a pat on the head from the approval body.

And this works, as in Part P I assume?

Another point you might like to try Andy, BS8436 cables do not prevent this problem because the contact cross section of the foil is very small and may well just burn away before the CPD opens. They are intended for fire resistance and electrical screening.
http://www.batt.co.uk/products...Tube/LSZH-Cable-BS8436

-------------------------
David
BSc CEng MIET
 01 April 2014 07:07 PM
User is offline View Users Profile Print this message



ennel

Posts: 51
Joined: 20 October 2003

Originally posted by: davezawadi

Another point you might like to try Andy, BS8436 cables do not prevent this problem because the contact cross section of the foil is very small and may well just burn away before the CPD opens. They are intended for fire resistance and electrical screening.

Originally posted by: AJJewsbury

They're meant not to - a nail penetration test is part of the standard (unlike FP etc) and the stated withstand (42,000 A²s for 1.0mm² and 1.5mm² cable and 60,000 A²s for 2.5mm² cables) is actually higher than that for the c.p.c. for equivalent flat T&E cables (13,225 A²s for 1.0mm² and 29,756A²s for a 1.5mm²).
But then we do have reports of c.p.c.s 'blowing away' during a fault, so perhaps even conventional copper ones aren't immune from such possible problems either.
- Andy.


No Dave, BS8436 cables are for far more than just fire resistance and electrical screening, although they do have those properties. And this 'extra feature' is the reason that BS8436 cables are required to be protected by RCD/RCBOs with type B tripping curves, which will operate at fault currents below that at which the earthed screening vapourises under 'nail test' conditions.

However it can be hard to convince a contractor who has installed type C RCBOs instead of the specified type Bs of this necessity, when his QS takes the view "but the Zs of the circuits concerned is less than the maximum permitted for type C breakers - so the circuits comply fully with BS7671".

ennel
 02 April 2014 10:20 AM
User is offline View Users Profile Print this message



Zoro

Posts: 300
Joined: 31 July 2011

The problem was not the screw, you will never stop screws being driven into cables. The threat to safety was the circuit had never been tested, but the Certifier the "Electricians Mate" Certified that it had. The prosecution was under HSE Section 7 legislation, not EAWR.

The Qualified Supervisor, who had not supervised the "Electricians Mate" then checked the Certificate, which had multiple errors and then signed the certificate as checked.

The Certifier the "Electricians Mate" had C&G Part 1 and over 35 years experience in the trade, stated that he was not an Electrician.

The Certifier said he did not "IR test " the immersion heater circuit, he Certified that he had. (It was a Heatstore unvented mains cylinder with two immersion heaters).
The QS signed the Certificate with those errors.

The Certifier was given information for the certificate from others whilst in the site hut. Including the supply which he Certified as TN-S, but in fact was TN-C-S, and labelled up as PME at the intake position.
The QS signed the Certificate with those errors.

The Certifier stated that the circuit had an RCD (which it did not) , then certified that that the 3 test results for that RCD were N/A. The installation was under the 16th Edition, so did not require one
The QS signed the certificate with those errors.

The Certificate stated phase/phase IR results, on a single phase installation.
The QS signed the certificate with those errors.


The problem is that the supervision and certification required by HSE legislation, is not met by the NICEIC QS system. This poses the serious question, when are the ESC/NICEIC going to change their position and require that the Certifier is Competent to do so under HSE legislation, not the QS sat in the office.

The stance from the ESC/NICEIC that, this would be to expensive, must concern the public, that people on the doorstep from an NICEIC enterprise could cost a lot, to make them Competent.

.

Edited: 02 April 2014 at 10:28 AM by Zoro
 01 April 2014 03:21 PM
User is offline View Users Profile Print this message



weirdbeard

Posts: 3116
Joined: 26 September 2011

Originally posted by: AJJewsbury
- hence it would have had a connection to earth via the immersion c.p.c. -



Wasn't it the immersion cpc that was blow apart by the fault?

-------------------------
:beer)
 01 April 2014 03:28 PM
User is offline View Users Profile Print this message



OMS

Posts: 22864
Joined: 23 March 2004

Originally posted by: weirdbeard

Originally posted by: AJJewsbury

- hence it would have had a connection to earth via the immersion c.p.c. -





Wasn't it the immersion cpc that was blow apart by the fault?


Apparently so - but there are likely to be other earth connections to the CWS pipework in addition to the bonding - shower, second element supply, boiler etc etc

Regards

OMS

-------------------------
Let the wind blow you, across a big floor.
 01 April 2014 03:15 PM
User is offline View Users Profile Print this message



AJJewsbury

Posts: 17795
Joined: 13 August 2003


Another point you might like to try Andy, BS8436 cables do not prevent this problem because the contact cross section of the foil is very small and may well just burn away before the CPD opens.

They're meant not to - a nail penetration test is part of the standard (unlike FP etc) and the stated withstand (42,000 A²s for 1.0mm² and 1.5mm² cable and 60,000 A²s for 2.5mm² cables) is actually higher than that for the c.p.c. for equivalent flat T&E cables (13,225 A²s for 1.0mm² and 29,756A²s for a 1.5mm²). But then we do have reports of c.p.c.s 'blowing away' during a fault, so perhaps even conventional copper ones aren't immune from such possible problems either.

- Andy.
 01 April 2014 03:27 PM
User is offline View Users Profile Print this message



AJJewsbury

Posts: 17795
Joined: 13 August 2003

Wasn't it the immersion cpc that was blow apart by the fault?

good point - although John did say "Circuit No. 3 supplied one of the immersion heaters in the boiler. " - suggesting that there might have been 2 or more immersions? As OMS said, chances are some other class 1 item was in contact with the pipework anyway.
- Andy.
 01 April 2014 03:36 PM
User is offline View Users Profile Print this message



John Peckham

Posts: 9097
Joined: 23 April 2005

There was a second immersion and the pipework was supplementary bonded.

-------------------------
John Peckham

http://www.astutetechnicalservices.co.uk/
 02 April 2014 09:05 AM
User is offline View Users Profile Print this message



phantom9

Posts: 1757
Joined: 16 December 2002

It takes one case like this to get everyone debating yet today there will be probably 100 people killed through several road accidents, the same tomorrow, the next day and the day after. ONE fatality in the scope of things leaves me to consider that this case is a genuine accident and nobody should have been prosecuted. More than one event contributed to the fatality. Plasterers installing the board on to the metal frame and screwing through the cable caused the fatality, not lack of testing. That is a failure to discover the damage to the cable caused by the person who screwed through it. He probably even knew he'd done it but the "who cares" attitude by workers on site means accidents are always going to occur. The plasterer caused it. It is "who touched it last" syndrome and it is totally unfair to prosecute a guy just because he signed a piece of paper. Electricians reading the case will know that, unless a strict supervision scheme is in place overseeing the electrical installation, insulation testing is rarely carried out. Real world and text book world. Poles apart.
 02 April 2014 09:10 AM
User is offline View Users Profile Print this message



phantom9

Posts: 1757
Joined: 16 December 2002

I just wanted to add that my ever present questioning of the value of equipotential bonding has led me to concur that bonding is not safe and it would be better to not bond anything at all. I believe in theis case that had no bonding been in place Emma Shaw would still be alive. A bold statement to make but true.
 02 April 2014 10:16 AM
User is offline View Users Profile Print this message



OMS

Posts: 22864
Joined: 23 March 2004

Originally posted by: phantom9

I just wanted to add that my ever present questioning of the value of equipotential bonding has led me to concur that bonding is not safe and it would be better to not bond anything at all. I believe in theis case that had no bonding been in place Emma Shaw would still be alive. A bold statement to make but true.


Don't be silly - it would need what is effectively an all insulated system to save Emma Shaw from this fault

Draw out the circuit paths - the victim would have received a shock if she touched any earthed metalwork - the HWS cylinder, hot or cold pipework, a class 1 appliance with a functioning CPC etc etc

Are you seriously suggesting that the solution would be to remove earthing and bonding from the system (and to eliminate naturally earthy components as well).

If you doubt the value of both main and supplementary bonding, then do a bit of basic research into the concept of touch voltage - then tell me it has no value - and I'll tell you in no uncertain terms that it has significant value.

As a starting point, the touch voltage driving curent through the impedance of the human body will be

Vt = If x R2

Then think about what R2 comprises - as a hint it is the resistance of the CPC back to the point of equalization (ie the point of bonding)

Now take a TN or TT system and determine that with our without bonding If won't change mutch - but R2 changes from just the impedance of the CPC within the building to the impedance of the CPC both within the building and the earth path outside the building right back to the transformer.

At a simple level you should see that if we multiply If by a bigger number then Vt must increase ?

Regards

OMS

-------------------------
Let the wind blow you, across a big floor.
 02 April 2014 12:00 PM
User is offline View Users Profile Print this message



sparkingchip

Posts: 11682
Joined: 18 January 2003

My eldest daughter and her partner have just bought their first flat on Monday of this week,the plumbing and electrical systems are identical to that in Emma Shaw's flat.

I'd better be a good dad and run some tests then upgrade the level of RCD protection, as only the sockets are protected, also show them the main switch, so if there are problems they know where to turn off the electric supply to the whole flat.

Andy
 02 April 2014 06:57 PM
User is offline View Users Profile Print this message



phantom9

Posts: 1757
Joined: 16 December 2002

Originally posted by: OMS

Originally posted by: phantom9



I just wanted to add that my ever present questioning of the value of equipotential bonding has led me to concur that bonding is not safe and it would be better to not bond anything at all. I believe in theis case that had no bonding been in place Emma Shaw would still be alive. A bold statement to make but true.




Don't be silly - it would need what is effectively an all insulated system to save Emma Shaw from this fault



Draw out the circuit paths - the victim would have received a shock if she touched any earthed metalwork - the HWS cylinder, hot or cold pipework, a class 1 appliance with a functioning CPC etc etc



Are you seriously suggesting that the solution would be to remove earthing and bonding from the system (and to eliminate naturally earthy components as well).



If you doubt the value of both main and supplementary bonding, then do a bit of basic research into the concept of touch voltage - then tell me it has no value - and I'll tell you in no uncertain terms that it has significant value.



As a starting point, the touch voltage driving curent through the impedance of the human body will be



Vt = If x R2



Then think about what R2 comprises - as a hint it is the resistance of the CPC back to the point of equalization (ie the point of bonding)



Now take a TN or TT system and determine that with our without bonding If won't change mutch - but R2 changes from just the impedance of the CPC within the building to the impedance of the CPC both within the building and the earth path outside the building right back to the transformer.

At a simple level you should see that if we multiply If by a bigger number then Vt must increase ?

Regards

OMS


OMS you are more educated than I so I will talk in simple layman's terms as to how I see this.

I understand the need for earthing. All circuits are earthed and the main earthing conductor completes the earthing of the circuits. The part where I disagree is bringing extraneous-conductive-parts in to the electrical system by placing bonding conductors on them. It is pure theory is it not that this earthing system comprising of earth, main bonding and supplementary bonding makes parts that would not otherwise be part of the electrical system safer if they do inadvertently acquire a voltage through a fault. It is a well known fact that CURRENT causes death not VOLTAGE. A voltage can be present on something but current will only flow if a circuit can be made. 50mA of current is sufficient to kill. Merely touching a live part if no current can flow will not kill you but you will get a painful shock if the voltage is big enough.

The metal frame in Emma Shaws case was made live because the earthing conductor was damaged and voltage was present on the frame by virtue of the screw driven in to the cable. So the frame was then live but no current was flowing it was at 230V potential. When water was added to the scenario current was finding a path driven by the voltage (voltage is the force driving the flow) and multiple fault circuits were present in the area where Emma Shaw was. Some of these circuits were created by virtue of the metal pipework being bonded and hence giving low impedance paths for electricity to use. When Emma grabbed hold of the stop[cock to turn off the water she was literally grabbing a circuit that directed multiple fault paths through her body because the pipework was at 0V potential and she was the connection to complete another fault path. My contention is that had there been no electrical connection from the pipework to earth that she would not have completed a circuit. She would have felt a shock and painful one but not nearly as big as the one that killed her.

Now all of this is purely hypothesis and just the way I see it. I cannot back any of this up with calculations because I have neither the time nor the ability to do it. It is based on intuition and gut feeling.
 02 April 2014 09:15 AM
User is offline View Users Profile Print this message



AJJewsbury

Posts: 17795
Joined: 13 August 2003

I believe in theis case that had no bonding been in place Emma Shaw would still be alive. A bold statement to make but true.

Not so - in this case the pipework would still have been solidly earthed by the 2nd immersion's c.p.c. Plastic pipework might have saved her though.
- Andy.
 02 April 2014 09:21 AM
User is offline View Users Profile Print this message



phantom9

Posts: 1757
Joined: 16 December 2002

She was crawling around on the wet floor and not receiving shocks. The fact she touched the water pipework killed her. It was bonded. Had it not been there was no fault path. This theory that bonded e-c-p's brings voltage to safe levels falls flat on its face. You have mentioned "a solid earth connection from the second immersion heater" but earthing a bonding are not the same. Plastic pipework is the same as not bonding. You remove the electrical conductivity. Plastic pipework insulates. Not introducing earth potential to an e-c-p is the same, you remove the opportunity for electric current to have a path to complete the circuit.
 02 April 2014 09:38 AM
User is offline View Users Profile Print this message



AJJewsbury

Posts: 17795
Joined: 13 August 2003

earthing a bonding are not the same.

True, but nevertheless both do effectively connect metal items to earth - so either can provide a return path for shock current.

Plastic pipework is the same as not bonding

Not quite - plastic pipework is the same as earth free or insulating location (as far as the plumbing is concerned).

- Andy.
 02 April 2014 10:26 AM
User is offline View Users Profile Print this message



mapj1

Posts: 12039
Joined: 22 July 2004

The problem with not bonding is that it is just
'indeterminate connection' and you run the risk of having a faulty water heater that makes all the pipes in the house a bit live, and a steady few hundred mA to ground through the water pipes, and no body notices, and nothing trips, until the fault voltage is exported to a place with a real terra-firma earth in some other way, such as the kids go to use the outside tap in bare feet.
I take the point about the relative accident rates, it is the case, as I noted above, she was jolly unlucky, and that combination of events was jolly unlikely, and could just as well still have arisen even if the paper trail had been OK.
I would not use one accident as an argument for not earthing metal service pipes however.
Actually for the record it's more like 10 people a day declared dead in RTAs in the UK, and between 5 to 10 times that hospitalised for at least overnight, and mostly its not even mentioned on the local news. Even this pales beside deaths from other causes including misdiagnosed or late diagnosis of avoidable medical conditions - I will contentiously assert that we would save many more lives scrapping part P, and paying the equivalent money that now goes to NICIEC et al, into
preventive clinical screening services of one sort or another.
If we take treasury life values, we might like part P to save about 100 people a year to be as cost effective as say moer bowel cancer screening - well as nothing like that many are electrocuted so it can't possibly compete.
The fact that this is true by a large margin makes me suspect that a lot of supposedly safety related rules and regs are really there for other social- management reasons, such as making fiddling your income tax harder or something. But that's just a personal gripe.

regards
Mike.

-------------------------
regards Mike


Edited: 02 April 2014 at 01:07 PM by mapj1
 02 April 2014 12:06 PM
User is offline View Users Profile Print this message



OMS

Posts: 22864
Joined: 23 March 2004

I will contentiously assert that we would save many more lives scrapping part P, and paying the equivalent money that now goes to NICIEC et al, into preventive clinical screening services of one sort or another.


The cost of Part P isn't the problem - from a consumer point of view it has no real cost and from an industry point of view the cost is very modest - as Government intended

In my opinion it's that modest cost that has fuelled the schemes to seek volume membership - and within that volume there has no doubt been a diminution of basic standards of competency to maintain market share.

When that's coupled with the idea of having a two tier "electrician" and "installer" system, then is it any wonder that some employers will seek to capitalise on the uncertainty of who is competent to do what.

I'd expect the total costs of scheme membership, instrument calibration etc to not exceed £1K/annum for most jobbing electricians - that's just over £20/week or less than 50p/hour on rates. Significantly less than that for SME's who can dilute the cost over several employees.

There's no doubt that we could get more safety for the same spend, but personally speaking, Part P simply addressed a missing link in the regulation covering domestic installations - collectively the Building Regs will provide a springboard to improve housing quality, safety and efficiency as we move foward.

Regards

OMS

-------------------------
Let the wind blow you, across a big floor.
 02 April 2014 12:14 PM
User is offline View Users Profile Print this message



AJJewsbury

Posts: 17795
Joined: 13 August 2003

Part P simply addressed a missing link in the regulation covering domestic installations

Although curiously the Emma Shaw case was brought under the Section 7 of the Health and Safety at Work Act. , rather than building regs, even though part P would have been in effect at the time of the work and (if I recall correctly) had an explicit provision for testing (old P2).
- Andy.
 02 April 2014 01:20 PM
User is offline View Users Profile Print this message



mapj1

Posts: 12039
Joined: 22 July 2004

But it was clearly more than 6 months after the installation - then the statute of limitations of the magistrates courts act 1980 section 127 or whatever it's been updated too by now kicks in, and muddies the water, as simply failing to meet building regs alone, is a non-inditable offence.
In this case, installing and failing notify or to inspect alone would be un-prosecutable after 6 months if nothing else happened. I think in certain special cases, like not meeting environmental standards, there is a longer time limit.

Of course, really its far more serious in this case as there are overrtones of conspiracy to deliberately fake results, not to mention the actual fatality itself, so it makes sense to use a law with more bite.
I still wonder what folk would be saying if the tests had actually been performed to standard, and had recorded a pass on the day. I'm reasonably confindent that eevn if not this time, there are situations where a screw could in principle catch the live core and a non-grounded something else that can be touched later, and still evade detection by typical test intstruments on a dry day. Perhaps we should have a higher IR test limit requiring investigation, at least for brand new installations?
regards M.

-------------------------
regards Mike
 02 April 2014 01:50 PM
User is offline View Users Profile Print this message



OMS

Posts: 22864
Joined: 23 March 2004

Originally posted by: AJJewsbury

Part P simply addressed a missing link in the regulation covering domestic installations


Although curiously the Emma Shaw case was brought under the Section 7 of the Health and Safety at Work Act. , rather than building regs, even though part P would have been in effect at the time of the work and (if I recall correctly) had an explicit provision for testing (old P2).

- Andy.


Indeed - what else could have reasonably be use.

Section 7 actually says:

7 General duties of employees at work.
It shall be the duty of every employee while at work -
(a)to take reasonable care for the health and safety of himself and of other persons who may be affected by his acts or omissions at work; and .
(b)as regards any duty or requirement imposed on his employer or any other person by or under any of the relevant statutory provisions, to co-operate with him so far as is necessary to enable that duty or requirement to be performed or complied with.

Same legislation used for example in the Menendez shooting at Stockwell

So the Part P duty to test was on the employer ? - and the employee failed to do so

Regards

OMS

-------------------------
Let the wind blow you, across a big floor.
 02 April 2014 03:04 PM
User is offline View Users Profile Print this message



AJJewsbury

Posts: 17795
Joined: 13 August 2003

Indeed - what else could have reasonably be use.

I was just wondering that if the HSAWA does indeed cover domestics, like this case, then where's the gap that part P is intended to fill? (I thought that part P covered only domestics as the HSAWA covered workplaces).
- Andy.
 02 April 2014 04:13 PM
User is offline View Users Profile Print this message



OMS

Posts: 22864
Joined: 23 March 2004

But the two guys involved were employees (or posibly self employed) so HASAWA will always apply to them.

The domestic client does not attract the same duties under HASAWA but it still applies to all those "at work"

Or at least that would be my thinking on it Andy

Regards

OMS

-------------------------
Let the wind blow you, across a big floor.
 02 April 2014 04:22 PM
User is offline View Users Profile Print this message



GeoffBlackwell

Posts: 3846
Joined: 18 January 2003

I found it strange that the HASAWA was used but there were two defence barristers (one for each defendant) and I am sure they would have moved to have the cases thrown out if the law used did not apply.

Regards

Geoff Blackwell
 02 April 2014 04:26 PM
User is offline View Users Profile Print this message



rocknroll

Posts: 9677
Joined: 03 October 2005

Domestic premises have no duties under HASAW it terminates at the service position, but this was about the actions of the employer and employees where it requires employers (and the self-employed) to ensure that non-employees (eg the general public, contractors and contract staff) do not have their health and safety adversely affected by the employer's actions, has this been an incident in the workplace then the actual death would have figured more highly in the case.

Now that a person has been found guilty the aggrieved party/s can persue this on their own through common law if they so want.

Building Regulations are generally minor technical offences and dealt with through common law, there is no Part P offence it reverts to Regulation 7, building work shall be carried out - with proper materials and a workmanlike manner, that is the legal bit.

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!"
-------------------------
 02 April 2014 05:50 PM
User is offline View Users Profile Print this message



AJJewsbury

Posts: 17795
Joined: 13 August 2003

So is part P just targeted at the DIYer then? Seems a bit overkill - and why all these employees being obliged to join competent persons schemes?
- Andy.
 02 April 2014 06:36 PM
User is offline View Users Profile Print this message



phantom9

Posts: 1757
Joined: 16 December 2002

Lets just be clear on one point. A Jury has found an electrician to be guilty of signing unchecked electrical work and falsifying test results.

The CAUSE of the accident is not down to the electrician. It was CAUSED by the screw penetrating the cable! All subsequent events were of a consequence of the screw being in the cable.

Now, the prosecution was made under the HASW Act because of misdemeanours on the part of the electrical testing of the installation and failure to find the fault. This is completely different to what CAUSED it. Can we be absolutely clear on this please.

The Law in this case has focussed purely on the electrical installation because it would be impossible to bring the person who screwed in to the cable to justice. In other words the failure of the electricians to find what was at the time potentially fatal damage to a cable has been the case NOT who killed Emma Shaw as it was the person who screwed in to the cable who did this. Had the screw not been put in to the cable the installation was completely safe. The electricians failed to find it so have been prosecuted for that.
 02 April 2014 07:02 PM
User is offline View Users Profile Print this message



Zuiko

Posts: 521
Joined: 14 September 2010

Phantom - the prosecution was certainly not made under the HASWA because of misdemeanours.

There is no such thing as a misdemeanour in English Law.

Those found guilty in a criminal court are guilty of a criminal offence.





Regarding the need for bonding - listen to OMS, he is right on this one.
 02 April 2014 07:33 PM
User is offline View Users Profile Print this message



geoffsd

Posts: 2342
Joined: 15 June 2010

Phantom - the water pipe would have been earthed by its connection to boiler and immersion.
In this case the bonding made no difference.


A few years ago an MP's daughter was killed because of another screw into a line conductor with no contact to the cpc..
This screw was attaching a metal kitchen hook to the wall.
The lady was killed when she touched the wall hook at the same time as her leg was touching the washing machine.

So, in this case it would have been better had the wall hook been earthed and the washing machine not earthed.
I think you will agree that no one would advocate that for every household.

Unfortunately, accidents happen and there is always an odd solution where it would not have happened.
 02 April 2014 08:24 PM
User is offline View Users Profile Print this message



OMS

Posts: 22864
Joined: 23 March 2004

I understand the need for earthing.

Good

All circuits are earthed and the main earthing conductor completes the earthing of the circuits. The part where I disagree is bringing extraneous-conductive-parts in to the electrical system by placing bonding conductors on them.

Think about that again - if they are extraneous, they already have a potential (usually earth potential) - if you touch a metal item with an earth fault and that extraneous conductive part at earth potential you experience a touch voltage - it's what we used to call an indirect contact shock.

If I bond that conductor to the MET the fault causing the aplliance case to rise in voltage also pulls up that extraneous part and the voltage between the parts (ie the touch voltage experienced by the person is reduced


It is pure theory is it not that this earthing system comprising of earth, main bonding and supplementary bonding makes parts that would not otherwise be part of the electrical system safer if they do inadvertently acquire a voltage through a fault.

It most certainly is not theory - it a physical fact - ohms law dictates it

It is a well known fact that CURRENT causes death not VOLTAGE.

LoL - you'll be telling me next that "it's the volts that jolt but the mills that kill" - it is incredibly difficult to seperate the amps from the volts when you have a resonably fixed impedance like a human body
OK - if you want to be a pedant, if I apply a voltage to an impedance, then we will have current - the value of current being dictated by the voltage and the impedance combination. As the human body impedance is broadly fixed, then less or more voltage means less or more current - ohms law again.

A voltage can be present on something but current will only flow if a circuit can be made.

Indeed, the human body has impedance so the circuit is always made if only by capacitive coupling - why do you think we have limits on systems like Medical IT arrangements that are protecting from micro shock - in those kind of cases we are taking about perhaps a few milliamps in a suppressed patient being fatal

50mA of current is sufficient to kill.

It's a lot less than that actually - depends on the person and where we apply it - a few mills will do the job once we are through the skin - don't forget the human body is just a resonably tough bag containing lots of conductive fluids

Merely touching a live part if no current can flow will not kill you but you will get a painful shock if the voltage is big enough.

You would need to be very highly insulated for no current to flow - and that's not practicable in reality. I suspect Emma Shaw was already experiencing some current flow before she touched earthy metalwork



Seriously, you need to research and understand the touch voltage concept - because if you let your current thinking drive your design approach regarding bonding of extraneous conductive parts (or not in your case) then that is truly dangerous.

Do not let a little knowledge cause you a problem- take the time to understand the basic science behind the reasons for earthing and bonding - trust me, they are rooted in good science

Regards

OMS

-------------------------
Let the wind blow you, across a big floor.
 02 April 2014 11:38 PM
User is offline View Users Profile Print this message



phantom9

Posts: 1757
Joined: 16 December 2002

Originally posted by: OMS



Seriously, you need to research and understand the touch voltage concept - because if you let your current thinking drive your design approach regarding bonding of extraneous conductive parts (or not in your case) then that is truly dangerous.

Do not let a little knowledge cause you a problem- take the time to understand the basic science behind the reasons for earthing and bonding - trust me, they are rooted in good science

Regards

OMS


Just to reassure you I do carry out main equipotential bonding! My debate is about trying to justify it. I have GN8 but not GN5. I will add that to my list.
 03 April 2014 02:39 PM
User is offline View Users Profile Print this message



mawry

Posts: 334
Joined: 26 April 2004

There's a book by BD Jenkins. Electrical installation calculations which has a nice bit on the Touch Voltage Concept in one of the appendices. You can get the latest version from Amazon for 20 odd quid.

Someone also posted on here a few years back a very nice spreadsheet that was very good at indicating the relationships between V, I and R1, R2 etc.
 06 April 2014 06:09 PM
User is offline View Users Profile Print this message



briandoherty

Posts: 313
Joined: 08 May 2004

Originally posted by: mawry
There's a book by BD Jenkins. Electrical installation calculations which has a nice bit on the Touch Voltage Concept in one of the appendices. You can get the latest version from Amazon for 20 odd quid.
Someone also posted on here a few years back a very nice spreadsheet that was very good at indicating the relationships between V, I and R1, R2 etc.

I guess there's a chance that the spreadsheet referred to is the one I spent rather more of my employer's time on than I ought to have done when there was money to be earned elsewhere....brian's fault current / touch voltage spreadsheet

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

Brian
 07 April 2014 07:27 PM
User is offline View Users Profile Print this message



Zs

Posts: 3877
Joined: 20 July 2006

http://www.dailymail.co.uk/new...fined-just-1-000.html

Daily Mail article for your information.

Zs
 08 April 2014 11:13 AM
User is offline View Users Profile Print this message



mawry

Posts: 334
Joined: 26 April 2004

That's the one Brian, nice work!
 08 April 2014 07:46 PM
User is offline View Users Profile Print this message



mikejumper

Posts: 2810
Joined: 14 December 2006

If testing had been carried out properly would it have picked up this fault?

If the screw just clipped the live conductor on it's way into the metal studwork, thereby connecting the two together, how would any of the insulation tests we usually do show this?
 09 April 2014 12:06 AM
User is offline View Users Profile Print this message



napitprofessional

Posts: 452
Joined: 08 March 2008

Originally posted by: mikejumper

If testing had been carried out properly would it have picked up this fault?



If the screw just clipped the live conductor on it's way into the metal studwork, thereby connecting the two together, how would any of the insulation tests we usually do show this?



In this case, insulation testing would have found the fault instantly. It was self-evident, therefore, that the testing had not been done - even though the (apparently) "industry standard" value of 200 meg was entered onto the forms, albeit in the wrong column.

Clearly, Anchor Building and Electrical (in line with so many others) subscribed to the ongoing notion that lack of measured test results should not stand in the way of producing a completed certificate ....

I wonder when the next "one-off" will occur?

-------------------------
B. Eng (Hons) MIET
 09 April 2014 10:50 AM
User is offline View Users Profile Print this message



Zoro

Posts: 300
Joined: 31 July 2011

Nobody should take comfort at the thought of not testing, in the case of Emma Shaw, that maybe the fault may not have been found by testing to BS7671.

By forensic examination and evidence given in court, the screw was touching both live and cpc, which IR tests before energisation would have found.

After the incident the IR tests carried out, gave a reading of 0.2M ohm, even when the screw threads had been blown away by the fault current.

No dead test were carried out, and test results were made up, and entered onto the certificate by the Non competent, Unqualified Certifier.

The QS certified that he had checked the NICEIC certificate, but it had multiple errors. The QS has a personal responsibility to supervise but he did not, he has a personal responsibility to check the certificate he did not.

Part P Schemes are based on the flawed NICEIC QS system, they do not require individual Competence I believe this was a contributing factor.

The fact that the NICEIC are fighting to retain this system on the basis that it would be to expensive is disgusting, especially when they are owned by the Electrical Safety Council, or whatever they are calling themselves this week.

It was good that the Select Committee rejected this propaganda and told the Schemes to comply with having individual Competence. The only expense would be to contractors that charge for an Electrician and don't supply one.

.
 09 April 2014 02:01 PM
User is offline View Users Profile Print this message



napitprofessional

Posts: 452
Joined: 08 March 2008

How will the public react to being charged more for what they already think they are paying for and getting .....

-------------------------
B. Eng (Hons) MIET
 02 April 2014 08:23 PM
User is offline View Users Profile Print this message



AJJewsbury

Posts: 17795
Joined: 13 August 2003

My contention is that had there been no electrical connection from the pipework to earth that she would not have completed a circuit.

I completely agree. The point is that the pipework would still have a connection to earth via the metal tank and the other class 1 immersion heater fitted into it via its c.p.c. (and probably a few other points on the system besides). Omitting bonding in most cases wouldn't remove all earth paths.

(Omitting bonding on a PME system also means that c.p.c. so things like immersion heaters may then have to carry all the diverted N current for the installation my themselves - probably not a good thing from a fire prevention point of view.)

- Andy.
 02 April 2014 10:30 PM
User is offline View Users Profile Print this message



Parsley

Posts: 1383
Joined: 04 November 2004

Phantom 9

If you haven't already got a copy I recommend you invest in GN5. The Ut and importance of bonding explanation in GN5 is better than the in GN8 IMO.

From what I've read it looks like the cause was a failure of basic protection or direct contact in old money not the bonding of the pipe work.
The accident was caused by poor workmanship by the installers and possibly lack of care by the dry liners. ADS didn't really come into it, it wasn't an earth fault per se. The basic protection section of GN5 also comments on the importance of precautions against damage by other trades during installation.

I think this accident demonstrates that the introduction of 30ma RCDs for domestic installations was a good idea.

A lot of construction sites aren't managed probably, who carries out the CoW role on most sites? It's why cold bridging is an issue and why performance of MVHR doesn't meet the design expectations. No wonder off site modular fabrication is becoming more popular with clients.

Regards
 02 April 2014 11:06 PM
User is offline View Users Profile Print this message



electricman

Posts: 871
Joined: 17 November 2005

Hello All,

It is such long time since I posted. I still pop by for a regular read but got out of the habit of posting.

The reason I post tonight is that last night I struggled to nod off thinking about the poor girl, dead, on her knees, head first under the sink. It really got me thinking and this reflection has continued today.

I have been an electrician now since 1981 and have worked at a lot of outfits both big and small and have to say that the fiddling is endemic in the industry. It is not the exception but the rule.

Two examples for you now..... one old and one new with a million skipped ones in between.

In the 80's I worked at the electric board as a domestic spark. There were 110 domestic sparks in the old Norweb. Now the Norweb area went from Buxton to Carlisle on the left hand side of The Pennines. I lived in Manchester and reckon I worked with perhaps thirty of them over a half decade. Every man was issued with an Edgcombe Peebles insulation/ continuity tester and a loop impedance meter. For you newbies out there they were a grey meter in yellow leather cases with real life moving needles!. Anyway I digress! The job sheets were very rudimentary. On the sheet there were simple test results. It said

IR ....... M.Ohms
EFLI........Ohms

I would say 9 out 10 sparks would put an 8 on its side in the first bit (that is the symbol for infinity) and 0.5 in the second, with the meters never leaving the boot of the car. Utterly shocking. In 5 or 6 years working there I came across half a dozen houses with no electrical earth whatsoever. If you multiply that up by the ones that were missed by the other 'electricians' it does not bear thinking about.

So, now thirty years later to the new tale from eh well today actually. I am working for a local contractor and was doing a board change on a holiday cottage that failed its PIR. I fired the board up and started with the first circuit which happened to be a cooker and its circuit. I R1+R2 tested the circuit and then did an insulation test. I tested between live conductors with the cooker switch off and got 125 Mohm. I then turned on the switch (to bring the cooker into play) and got about 15Mohm if I remember rightly. Now, because I have been doing the job a long time, I reckon these figures are fine. A little leakage on the cooker and a bit of damp in round the switch perhaps. The contractor who employs me left the 'fail' PIR for me to work the address off and so on and I was shocked to see the figures for the cooker I just did. Everything was above 299MOhm

So there it is folks. The clowns that killed the poor girl are not rogues or a rarity. No, I am like the kid in that Bruce Willis moivie that sees dead people. I have been round them all my life and felt compelled to say it.

-------------------------
"You're a crackpot till you hit the jackpot!"
Werner Von Braun 1969
 03 April 2014 02:37 PM
User is offline View Users Profile Print this message



ericmark

Posts: 329
Joined: 12 February 2008

Like "electricman" I look back at what I have done and think there by the grace of god goes I. In my latter years I was far more into the inspection and testing but at about the same time that this all happened the builders doing my mothers wet room ran off into the Welsh hills never to be seen again. So my son and I took over the job. I informed the LABC what had happened and said we were taking over. The inspector arrived and asked about who would test my son with C&G 2391 and PLI said he would but this was rejected by inspector. He said my dads got a degree in electrical and electronic engineering can he sign it and he agreed I could sign the installation certificate. I did have a C&G 2391 but this was not told to the LABC inspector and to be frank nothing taught on my degree course helped with inspection and testing.

Work was done I filled in paper work delivered to local shire hall and after a week or so a completion certificate arrived in the post the LABC inspector never visited the house after that first visit. So in real terms he did exactly the same as the NICEIC QC guy. OK nothing went wrong but the Government example shown did seem to be just sit in your office and shuffle paper. Unlike the semi-skilled worker the LABC inspector had no idea of how good my work would be. Also since I did not design that part was left unsigned and there was a note in the exceptions that design was by building firm and items fitted by them were not covered by the certificate which included fitting a new consumer unit.

I really do feel sorry for the NICEIC QC guy he only did the same as government inspectors at the time showed was required by example.
 04 April 2014 09:20 AM
User is offline View Users Profile Print this message



Zoro

Posts: 300
Joined: 31 July 2011

Originally posted by: ericmark

Like "electricman" I look back at what I have done and think there by the grace of god goes I. In my latter years I was far more into the inspection and testing but at about the same time that this all happened the builders doing my mothers wet room ran off into the Welsh hills never to be seen again. So my son and I took over the job. I informed the LABC what had happened and said we were taking over. The inspector arrived and asked about who would test my son with C&G 2391 and PLI said he would but this was rejected by inspector. He said my dads got a degree in electrical and electronic engineering can he sign it and he agreed I could sign the installation certificate. I did have a C&G 2391 but this was not told to the LABC inspector and to be frank nothing taught on my degree course helped with inspection and testing.

Work was done I filled in paper work delivered to local shire hall and after a week or so a completion certificate arrived in the post the LABC inspector never visited the house after that first visit. So in real terms he did exactly the same as the NICEIC QC guy. OK nothing went wrong but the Government example shown did seem to be just sit in your office and shuffle paper. Unlike the semi-skilled worker the LABC inspector had no idea of how good my work would be. Also since I did not design that part was left unsigned and there was a note in the exceptions that design was by building firm and items fitted by them were not covered by the certificate which included fitting a new consumer unit.

I really do feel sorry for the NICEIC QC guy he only did the same as government inspectors at the time showed was required by example.

Yes LABC still guess at what the requirements for Certifying Electrical Installations are, even after nine years of Part P and the Schemes providing training for them.

With multiple basic errors on the Certificate, I am not that sympathetic to the NICEIC QS.

It should be a warning for all QS's, there is a personal legal responsibility when they sign a Certificate, Section 7 now carries a custodial sentence.

.
 06 April 2014 03:53 PM
User is offline View Users Profile Print this message



John Peckham

Posts: 9097
Joined: 23 April 2005

When the 2 suspects were arrested and interviewed under caution the police asked how long would it take to carry out an inspection and test on a new flat? About half a day came the answer. The detective sergeant then asked the QS how it was on one day a person had signed certificates indicating they had tested 7 flats on one day, 8 on another day and on a Friday when they went home early 13 flats?

-------------------------
John Peckham

http://www.astutetechnicalservices.co.uk/
 08 April 2014 11:19 PM
User is offline View Users Profile Print this message



electricman

Posts: 871
Joined: 17 November 2005

About 15 years ago, I was working in shop fitting. The joiners threw up a jumbo stud wall and boarded one side in a couple of hours. I wired a 2.5 for a till socket. I drilled a hole at the top of the wall and fitted a brass bush and lockring. I dropped the conductor inside the board and coiled it up for the next shift...Meanwhile, the joiners boarded the other side and we went back to the digs.
The next morning the decorators were starting to tape the joints and I was ready to connect up. As always, I did a quick IR test and got a reading between L and E, not off the scale, as one would expect you...but nowhere down at the minimum allowed. When I tested between the screws in the board and L I got continuity. I left the megger on its ' bell' setting and started removing screws. Around the fifth screw removal sent the bell set to silence and a perfect reading.
It was just another day in my life where I remarked to myself the usual questions....

1 how many sparkies would bother testing 10 metres of cable pulled in in that sort of job
2 If they were confronted with a bum reading, how many would ignore it and crack on

When the regulations demanded that RCD protection be required for metal stud walls it came not a moment too soon.

-------------------------
"You're a crackpot till you hit the jackpot!"
Werner Von Braun 1969
 08 April 2014 11:23 PM
User is offline View Users Profile Print this message



AJJewsbury

Posts: 17795
Joined: 13 August 2003

If testing had been carried out properly would it have picked up this fault?

If the screw just clipped the live conductor on it's way into the metal studwork, thereby connecting the two together, how would any of the insulation tests we usually do show this?

In this particular case, JP reported that the c.p.c. had been blown away by the fault - suggesting that the screw initially hit L + c.p.c. - so even the simplest of insulation test should have spotted that.

It could very easily have been different though - as you suggest I doubt an insulation test would spot a screw into L alone, and the outcome could have been identical.

Similarly the Danny Edwards case where L & c.p.c. had been reversed at the socket - had the socket been on a radial, the normal "R1+R2" test as frequently taught wouldn't have spotted the problem before energization.

The courts and public have this quaint idea that testing will find any fault - while the real world is often a little less perfect (just ask any software developer).

I think we might be able to do better though. In the case of screws through hidden cables, it seems to me that the 'double insulation' approach is flawed as it clearly isn't robust enough for service conditions (people will put nails & screws into walls where they want, regardless of any 'safe zones' we might dream up). So the obvious alternative is real ADS - i.e. put earthed metal between the live conductors and any potential victims. MICC, SWA or steel conduit - or my current favourite at the moment - BS 8436 cables. I see it as catching the problem as it happens, not hoping to catch it at some later date when some poor victim completes the circuit to earth and hoping the RCD has been exercised recently. At the very least BS 8436 cable makes the insulation test viable again.

- Andy.
 09 April 2014 04:42 PM
User is offline View Users Profile Print this message



mikejumper

Posts: 2810
Joined: 14 December 2006

Originally posted by: AJJewsbury

If testing had been carried out properly would it have picked up this fault?



If the screw just clipped the live conductor on it's way into the metal studwork, thereby connecting the two together, how would any of the insulation tests we usually do show this?


In this particular case, JP reported that the c.p.c. had been blown away by the fault - suggesting that the screw initially hit L + c.p.c. - so even the simplest of insulation test should have spotted that.
- Andy.

Indeed it would.
I should have re-read JP's post.

If we know that test results are often made up and that even when they're done properly not all faults show up then I suppose what we install and how we install it has change to allow for that.

Another thought on this:
(I'm assuming the cable was flat twin & earth.)

In a situation like this wouldn't it have been better for both conductors to be blown away rather than the one being able to withstand the fault long enough to allow the other to be destroyed?

Would the outcome have been different if the cpc had the same csa as the live and was insulated in the same way?
 09 April 2014 05:14 PM
User is offline View Users Profile Print this message



OMS

Posts: 22864
Joined: 23 March 2004

All good points Mike,

What we've learned here is that inspection has fallen lower in the heirarchy than testing - there is a reason for the order of the words and I've always favoured inspection supported by testing at the correcty way to do things - rather than approach that makes inspection subordinate to testing.

We've also learned that proper installation methods and correct materials ie the selection and erection of systems is important.

As our IT chums like to say about "quality"

You can design it in
You can can install it in
But you can't test it in

So I would say that we need a focus on preventing the defects rather than quality testing in reality.

It's highly likely that full sized insulated CPC's would be an asset, however, in this case, the damage by the screw could easily remove "material" and result in unequal condictor sizes anyway with the same outcome.

As Andy mentioned above we need an earthed screen around live cores to ensure earth faults cause disconnection before live parts contact conductive unearthed components - we need more attention by installers to exactly what they do - I've seen enough "hanging gardens of Babylon" on new builds to say that the probability of this incident must be resonably high - I've also seen enough installations in metal frame systems to know that with just a little care and attention, coupled with appropriate programming of trades on site, can virtually eliminate the problem of screws through cables. Even a bit of loose plastic conduit can cure this issue of trapped cables.

Regards

OMS

-------------------------
Let the wind blow you, across a big floor.
 10 April 2014 08:56 AM
User is offline View Users Profile Print this message



psychicwarrior

Posts: 683
Joined: 18 October 2010

@Davezawadi

i was thinking the same thing.... why shouldnt it bonded ........yes i know its not extraneous [im presuming in this case], so maybe the old argument of introducing more of a problem by unnecessary bonding is less an issue than not bonding in some situations ..... electricity eh......'funny ' stuff



as said earlier up, thankfully a rare but quite upsetting case none the less.

i hope this doesnt develop into a case to allow panic regulating and futher empowering the already questionable governance and bodies present in this industry.

let good sense and reason prevail i hope, driven by those that know! (who ever they may be)
 11 April 2014 05:54 PM
User is offline View Users Profile Print this message



napitprofessional

Posts: 452
Joined: 08 March 2008

If good sense and reason prevailed we would require those who carry out electrical work to know what the hell they are doing - the trade understands, but an "industry" stands in the way ....

-------------------------
B. Eng (Hons) MIET
 12 April 2014 11:46 AM
User is offline View Users Profile Print this message



davezawadi

Posts: 4259
Joined: 26 June 2002

I have often commented about the bad idea of earthing everything in sight, but this is slightly different. As OMS admits, this is not an unknown problem with metal studwork, and as it is all covered up there is much less downside of making a conductive environment and the consequent increased danger of shocks. Using cables with metal sheaths is all very well, as is bits of conduit inside the studwork, but both are somewhat inconvenient in otherwise T&E installations. This construction method seems to create a significant extra risk compared with traditional construction, because cable positioning is obviously critical to safety and cannot be inspected properly. Bonding to the local CPC would be very low cost and would not appear to have much downside in terms of additional safety, particularly if we have RCD protection as well.

-------------------------
David
BSc CEng MIET
 12 April 2014 12:33 PM
User is offline View Users Profile Print this message



sparkingchip

Posts: 11682
Joined: 18 January 2003

If there was local bonding from the immersion heater local isolation switch terminals at the end point of the circuit to the metal stud with a broken CPC it wouldn't have achieved anything would it?

Andy
 12 April 2014 01:21 PM
User is offline View Users Profile Print this message



John Peckham

Posts: 9097
Joined: 23 April 2005

522.6.103 Covers the installation of cables in walls made of metal components. For some bizarre reason the sensible requirements of this section need not be applied if the installation is under the supervision of a skilled or instructed person. How the skilled or instructed person can exercise some sort of magic power over cables sandwiched inside a wall is one I cannot comprehend.

I think the skilled or instructed person requirement has disappeared from the AMD 3 DPC but I have managed to corrupt my copy. Can anyone direct me to the link to find it or alternatively send me a copy please?

Edit

Just found the DPC on this site. The DPC does away with the magic powers of the skilled or instructed person. Cables not mechanically protected will in the future need RCD protection.

-------------------------
John Peckham

http://www.astutetechnicalservices.co.uk/

Edited: 12 April 2014 at 01:30 PM by John Peckham
 12 April 2014 06:28 PM
User is offline View Users Profile Print this message



weirdbeard

Posts: 3116
Joined: 26 September 2011

Originally posted by: John Peckham

522.6.103 Covers the installation of cables in walls made of metal components. For some bizarre reason the sensible requirements of this section need not be applied if the installation is under the supervision of a skilled or instructed person. How the skilled or instructed person can exercise some sort of magic power over cables sandwiched inside a wall is one I cannot comprehend.



Hi John, with regards to the case in question it seems that the initial sandwiched cable failure was a breach of the 'good workmanship' reg 134.1.1, in the fundamental principles section....ie...the cabling was not installed in such a way to avoid damage by the boarders.

The supervision of a skilled and instructed person only comes into play once that person has been handed over a proper and safely installed installation.

-------------------------
:beer)
 12 April 2014 06:51 PM
User is offline View Users Profile Print this message



sparkingchip

Posts: 11682
Joined: 18 January 2003

Over the years as a carpenter, partition installer and electrician I have worked on all types of partitions used in modern British housing over the last thirty years.

75mm lightweight concrete blocks built off timber sole plates over the floorboards.
Timber stud walls of varying thicknesses both site and factory built.
Stramit partitions consisting of large slabs of straw.
Paramount partitions consisting of two sheets of plasterboard with a cardboard box inner.
Laminated plasterboard partitions consisting of three or four sheets of plasterboard glued together.
Metal stud partitions.

With both laminated plasterboard and metal stud the electricians first fix leaving the cables hanging down from the ceiling or sticking up from the floor and it is the job of the partition erectors, not the electricians, to put them into their final position.

So the partition erectors have a responsibility to ensure that the cables are installed correctly as well as the electricians in both laminate and metal stud partitions.

Andy
 12 April 2014 08:11 PM
User is offline View Users Profile Print this message



weirdbeard

Posts: 3116
Joined: 26 September 2011

Originally posted by: sparkingchip


So the partition erectors have a responsibility to ensure that the cables are installed correctly as well as the electricians in both laminate and metal stud partitions.


But....getting them to put their signature for their part of the electrical installation isn't so staightforward....afterall they're not 'electrically skilled'?

Much better practice to make sure the first fix cannot be compromised by subsequent trades, even if it does take a little longer to do?

-------------------------
:beer)
 12 April 2014 10:57 PM
User is offline View Users Profile Print this message



sparkingchip

Posts: 11682
Joined: 18 January 2003

With laminate and metal studs partitions there is not actually anything in place when the electrician first fixes for the cables to be placed, it has nothing to do with taking more time.

There is nothing in place to position cables or boxes.

The only time there was an exception was when I worked alongside the Renelec guys on a hospital where the metal partition erection stopped part way through because plastic conduit was being used as part of the wiring system. So the partition erectors installed the metal frame and boarded one side then I installed noggins and pads to support wall mounted equipment whilst a guy from Renelec installed the conduit.

On every other job with both laminate and metal stud twin and earth was hung in place for the boarders to pull through the boards with voids left in the partition so that in the electrical second fix cutouts coulds be made and drylining boxes installed, with marks on the ceiling or floor to indicate the height the cable was required to be brought out at.

Its all system building, which works fine so long as everyone on the team is neat and cares about the standard of their work..

The number of guys who have worked on volume housing sites such as those in the 1980's are thinning out and the young blood lack the speed and skill that was built up by the older tradesmen by repeating the same tasks over and over again,

I was working with electricians who only ever did 1st fixes, normally wiring two 2/3 bed houses a day or one 4/5 bed then a guy who only did 2nd fixes came along and did the 2nd fix. The best firms also had guys who did a 3rd fix where they installed the CU testing, inspecting and commissioning as they went along. The 1st and 2nd fixing guys never did any testing on these firms.

In amongst all this obsession with level 3 qualifications just remember the original City and Guilds levels "Craft" now level 2, "Advanced Craft" now level 3 and "Technician" now level 4.

A "Craftsman" level 2 should be more than capable of undertaking everyday installation work on domestic properties and is not just a "electricians mate" particullary with over thirty years experience, however that person should not be working out of scope and undertaking inspecting and testing without the additional training and qualification to do so and a "qualified supervisor" should be ensuring that they are not doing so or providing them with inaccurate test results for certificates that they as a QS are signing off.

Andy
 12 April 2014 04:02 PM
User is offline View Users Profile Print this message



phantom9

Posts: 1757
Joined: 16 December 2002

By thinking through the possibilities would it not be easier to ban routing electric cables through metal framed stud walls? In other words remove the hazard and the risk of the Emma Shaw incident would never arise again. Timber framed studwork has been used extensively for decades and I am not aware that there is any shock hazard associated with the timber frame in the same way that metal studwork has. It is far easier to remove the hazard than to try to impose strict regimes for electricians to adopt to make the hazard safe. Ban the use of metal frames stud partitions as wiring routes. There is no need for them.
 12 April 2014 05:44 PM
User is offline View Users Profile Print this message



Grobbyman

Posts: 378
Joined: 14 August 2005

Well our European friends seem to use them without killing too many people.
Perhaps we can learn something from them.
 12 April 2014 06:11 PM
User is offline View Users Profile Print this message



Zoro

Posts: 300
Joined: 31 July 2011

Originally posted by: Grobbyman

Well our European friends seem to use them without killing too many people.

Perhaps we can learn something from them.


Our European friends certainly could teach the UK something.

The job is only as good as the person that does it, no matter what the regulations say.

They use individual competence as HSE Section 7 requires, the Schemes and their Owners don't want to that, because it would be too expensive for them.
 12 April 2014 11:26 PM
User is offline View Users Profile Print this message



Fm

Posts: 2032
Joined: 24 August 2011

Why let joiners pull cables? Thats just asking for trouble

All my jobs see one side sheeted and wiring/containment installed. And the second sheet isnt installed until its signed off.

Allways works for me, however we tend to look for more than the minimum standard to comply
 12 April 2014 11:37 PM
User is offline View Users Profile Print this message



sparkingchip

Posts: 11682
Joined: 18 January 2003

If I had been designing, it would have been timber studding for partitions, with the stud erected, electrical first fix completed then both sides boarded.

That aside huge numbers of houses and flats have been completed with laminate and metal stud partitions with the boarders placing the cables in their final positions without any issues.

I didn't devise the systems, just reporting on them.

Andy
 12 April 2014 11:40 PM
User is offline View Users Profile Print this message



Fm

Posts: 2032
Joined: 24 August 2011

No doubt using fast fix boxes!
Get a dwang in and a metal ko box
 13 April 2014 12:04 AM
User is offline View Users Profile Print this message



sparkingchip

Posts: 11682
Joined: 18 January 2003

Dwang?

I had to Google that:
"Dwang
From Wikipedia, the free encyclopedia
For the term nogging used for infill in timber-framed buildings, see brick nog.


Platform framing
In construction, a nogging[1] or nogging piece[2] (England, Australia), dwang (Scotland,[1] South Island, New Zealand,[3]) blocking (North America), or noggin (North Island, New Zealand),.[4] They are also simply called nogs in New Zealand and Australia (No reference). They are horizontal bracing pieces used between wall studs or floor joists to give rigidity to the wall or floor frames of a building. Noggings may be made of timber, steel, or aluminium.
 13 April 2014 09:25 AM
User is offline View Users Profile Print this message



phantom9

Posts: 1757
Joined: 16 December 2002

Yes good post, Andy. The nogging is used to give rigidity, as you say, and braces the timber studs to stop them twisting. The same are used in floor joist systems where they have the added affect of reducing the span of the joist. Long joists can often be fitted with two noggins at third points.
 14 April 2014 10:13 AM
User is offline View Users Profile Print this message



OMS

Posts: 22864
Joined: 23 March 2004

Noggins are principally to provide "racking strength" in a framing system

The same effect can be achieved with the overboarding system - for example overboarding with an OSB board below the PB can eliminate the need for noggings entirely - and potentially provide all the fixing points required

All this nonsense about banning metal stud partitions is just that - as is the moaning regarding - "but we can't fix it to anything" - designers need to select systems that are appropriate for the construction methods

I must have worked on, designed, supervised installed and modified endless final circuit arrangements in metal framed partitions - asking for, or adding yourself, a few sections of "C stud" and putting the cable in place so as to avoid the obvious "hanging gardens" and subsequent entrapment problems is just simply a question of good workmanship and appropriate work face phasing - it may however require the use of a bit of suitable containment - god forbid

As I said earlier:

We've also learned that proper installation methods and correct materials ie the selection and erection of systems is important.

As our IT chums like to say about "quality"

You can design it in
You can can install it in
But you can't test it in

So I would say that we need a focus on preventing the defects rather than quality testing in reality.


Varying forms of construction is nothing new - electricians need to step up and start acting like professional members of an installation team instead of circling the wagons and moaning to each other that no one understands them - if you need fixing pads etc then ask for them.

Basically, Emma Shaw died as a result of a rough as **** approach to construction - even the most basic of site management should have in place a process such as FM described above - regardless of the choice of stud materials - and the so called tradesmen need to respond to that.

I've often asked site operatives what they are doing - most of the time you get a response of "putting in some sockets for this room, mate - why, what's it to you ?" - sometimes however you get " I'm helping to construct this new school/hospital/office, mate - it'll be a proper job when we finish"

Go Figure !

Regards

OMS

-------------------------
Let the wind blow you, across a big floor.
 14 April 2014 10:32 AM
User is offline View Users Profile Print this message



potential

Posts: 1774
Joined: 01 February 2007

Originally posted by: OMS

I've often asked site operatives what they are doing - most of the time you get a response of "putting in some sockets for this room, mate - why, what's it to you ?" - sometimes however you get " I'm helping to construct this new school/hospital/office, mate - it'll be a proper job when we finish"
Go Figure !
Regards
OMS

Absolutely spot on.
On the few occasions I've been the bystander (manager of the business) and had "electricians" working in the premises that is exactly the type of behaviour they have shown.
They behave as if they are a law unto themselves and covetously and unpleasantly react to anything they haven't thought of themselves.
They get short shrift from me, life is too short to tolerate little hitlers doing a relatively simple job.
Statistics

New here?

  • To participate in discussions, please log in and introduce yourself.

See Also:



FuseTalk Standard Edition v3.2 - © 1999-2022 FuseTalk Inc. All rights reserved.

 
..