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Topic Title: We never learn, do we ?
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Created On: 12 May 2013 02:23 PM
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 12 May 2013 02:23 PM
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OMS

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Well, it's happened again, needlessly.

Point 4 et seq

Another two avoidable deaths to add to the earlier Hertfordshire incident - and yet still we have people who can't or won't clip the damn cables.

OMS

-------------------------
Failure is always an option
 12 May 2013 02:43 PM
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slittle

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Tragic, but to be fair if it's not that hot then any plastic clips will have joined the rest of the heap on the floor.

I've got some pics of a cottage in R'n'Rs part of the world which went a week or so ago (belongs to a customers in-laws). The amount of stuff hanging from what remains of the ceiling could be an issue.

The other issue of course will be the BA crews committed with live wires hanging down around them until the DNO arrives to isolate (if possible). Perhaps as an industry we need to look at going back to something like the buckle clips that don't melt/burn

Stu
 12 May 2013 03:05 PM
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sparkingchip

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Reading that through it is easy to see the issue.

Picking up on this paragraph:
"6 It is recommended that Building Regulations are amended to ensure that all
cables, not just fire alarm cables, are supported by fire-resistant cable supports.
This could be achieved by an amendment to BS 7671 (2008) Institute of Electrical
Engineers Wiring Regulations."

Removing the option to put a bit of sticky backed PVC minitrunking and expecting twin and earth cables to be neatly installed with Saren Buckle clips or similar will challenge some installers and will be questioned on cost grounds by clients.

There is a culture of trying to be the fastest installer in town rather than ensuring neatness and durability.

In this particular case though it actually reads as it was fire rated cable in PVC mintrunking, so the support and fixing did not match the cable, allowing the cables to drop and get caught between the back of the fire fighters necks and the tanks of the breathing apparatus. But it could happen with any surface mounted cable with supports and fixings that will readily melt in a fire.
 12 May 2013 03:43 PM
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OMS

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In this particular case though it actually reads as it was fire rated cable in PVC mintrunking, so the support and fixing did not match the cable


Which is why BS 5839 requires the clips to match the fire resistance of the cabling system.

That was a lesson learned from Hertfordshire and apparently ignored here.

More generally, any sensible designer looks to use containment that secures cables in the event of fire - particularly in circulation routes. Metal trunking and PVC conduit would be a good example, with the trunking in the circulation and punching through to the rooms in PVC conduit.

Voice and data on primary runs of steel tray or basket would be another

Installers don't like it - I've lost track of the requests from installers to change to T&E as "value engineering", do I have to use metal cored ty wraps, do i have to use armoured cable cleats, we normally use cable ties etc etc etc

There is no value in the engineering if it kills people is there - it's the irony of a contractor pointing out to me the other day that he always uses LSF cable regardless - as he was busy tie wrapping it to anything available in the ceiling voids

regards

OMS

-------------------------
Failure is always an option

Edited: 12 May 2013 at 04:06 PM by OMS
 12 May 2013 04:01 PM
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rogersmith7671

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This very sad event has nothing whatsoever do do with installers or "city and guilds level 3 only electricians" or even fire alarm installers.
However this installation in a large block of flats has everything to do with the designer and their stupid consultants who specified the job in the first place.
The report also call for training and awareness guidance for firefighters in respect of these sorts of particular hazards.
If you are being shown this thread and others as examples of installer "incompetence" by third parties in order to justify a reduction in your final payment to a contractor, please think again.
 12 May 2013 04:43 PM
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OMS

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This very sad event has nothing whatsoever do do with installers or "city and guilds level 3 only electricians" or even fire alarm installers.


Really - was it the little naughty people who came along and removed all of the metalic fixings then - or perhaps they were never there in the first place ?

However this installation in a large block of flats has everything to do with the designer and their stupid consultants who specified the job in the first place.


It's social housing - the specification probably said "Provide a fire alarm system to category XYZ in acordance with BS 5839.2002 and current amendments" - there is no suggstion a consultant was ever involved - there is most certainly a suggestion that an installer was however.

The report also call for training and awareness guidance for firefighters in respect of these sorts of particular hazards.


Stable door, bolted, gone, horse - yes fire fighters should be aware of the problem, but it's not the highest risk when running into a smoke filled building with a BA set on - isn't this a matter for installers to follow the basic minimum provisions of the standards - they are signing a certificate to that effect.

If you are being shown this thread and others as examples of installer "incompetence" by third parties in order to justify a reduction in your final payment to a contractor, please think again.


Contractors and others, should carefully read and understand BS 5839-1 and in particular, from section 26.2:

f) Methods of cable support should be !non-combustible and such that circuit integrity will not be reduced below that afforded by the cable used, and should withstand a similar temperature and duration to that of the cable, while maintaining adequate support.
NOTE 8 - In effect, this recommendation precludes the use of plastic cable clips, cable ties or trunking, where these products are the sole means of cable support.
NOTE 9 - Experience has shown that collapse of cables, supported only by plastic cable trunking, can create a serious hazard for fire-fighters, who could become entangled in the cables.

my emphasis in bold

Note 9 arose from the Hertfordshire incident several years prior to this one.

Totally avoidable in my view.

Regards

OMS

-------------------------
Failure is always an option
 12 May 2013 05:27 PM
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perspicacious

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As far as I'm aware, for the last 20 years or so, every drum of soft skinned cable has a label on it that reminds the installer, along the lines of, that if it is to be used for fire safety services, that the cable shall be supported with fire resistant fixings.

Regards

BOD
 12 May 2013 05:33 PM
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ebee

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Originally posted by: rogersmith7671

This very sad event has nothing whatsoever do do with installers or "city and guilds level 3 only electricians" or even fire alarm installers.

However this installation in a large block of flats has everything to do with the designer and their stupid consultants who specified the job in the first place.

The report also call for training and awareness guidance for firefighters in respect of these sorts of particular hazards.

If you are being shown this thread and others as examples of installer "incompetence" by third parties in order to justify a reduction in your final payment to a contractor, please think again.


As most of you will have realised, I enjoy making a daft quip or post on occasion because I have a silly sense of humour.
However I do not think this topic is a joking matter.
But I fail to see that any of the points quoted above are intended to be taken seriously at all.

-------------------------
Regards,
Ebee (M I S P N)

Knotted cables cause Lumpy Lektrik
 12 May 2013 06:16 PM
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SKElectrical

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I think OMS is saying: please take time to use better quality products, be they metal trunking in main corridor runs, or armoured clips for cable in trunking or out of trunking.
I recently tie wrapped an LSF cable in a ceiling void with plastic tie wraps where there was no tray for support. Hmnn. Letters like that above will certainly deter me in future.
I would welcome changes to the building regulations on this matter - although I don't think the right place for a clause is in BS7671. Lastly, whilst, I welcome changes, I hope that they are not excessive / impractical, and any such changes are discussed and agreed with the consultation of practising electricians.
 12 May 2013 06:28 PM
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OMS

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What I'm actually saying, is that we have all the mechanisms in place for this now, without changing anything - we have requirements in standards and we have duties on designers (and a lot of installers/electricians are designers) under the CDM regs and other statutory instruments. What we are not seeing is even a bare inkling of common sense in the design, selection and erection of electrical systems

This, if it finds its way into BS 7671 and building regulations will be a classic case of regulations being about 2 steps behind the cutting edge of worst practice. I'm not saying we need miles of metallic containment - just the occasional loop of all round band if you really must just sling it into ceiling voids

Regards

OMS

-------------------------
Failure is always an option
 12 May 2013 07:19 PM
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perspicacious

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"I recently tie wrapped an LSF cable in a ceiling void with plastic tie wraps"
"Lastly, whilst, I welcome changes, I hope that they are not excessive / impractical, and any such changes are discussed and agreed with the consultation of practising electricians."

Has anyone got a new drum of fire resistant cable so that they can post details from the label about the fixing methods required?

My understanding is that the concept of the soft skinned cable is that you allow it to burn and the resultant "clinker" that remains, acts as an insulator preserving cable functionality. However, should this clinker "fall off", the cores could touch and lead to failure of intended function. Hence the requirement from 20 years or more ago to fix with fire resistant fixings every 300 mm (from memory) so that the "clinker" stays in place.

There is then the secondary function of keeping it in place to avoid it being a physical hazard when it falls.

Meanwhile, the only online info I can find from any manufacturer's www is below, which doesn't seem to mention that since the introduction of soft skinned cable in 1980's? it appeared to be a manufacturer's requirement to use fire resistant fixings if the cable were to be used in such a situation (to keep the "clinker" in place)

Regards

BOD

Posted: 27/01/06 16:56:57
Fire Resistant Cable Fixing
Terry Journeaux of Prysmian Cables outlines the new requirements of the code of practice for fire alarm systems BS5839-1:2002 in respect of cable fixings and gives details of a new fixing method.

Compared with BS5839-1:1988, the 2002 edition introduces some significant changes affecting cable selection and installation:

.The use of fire resisting cables is now recommended for all manual call point and automatic fire detector circuits.
.The use of fire resisting cables is also recommended for all final mains power supply circuits
.Two different levels of resistance of cables to damage during the course of fire are recognized, and recommendations for application of each type are provided
.New test requirements for cables introduced
.Recommendations for networked systems, particularly in respect of cable types, are included
.New guidance on segregation
.Restrictions on use of multicore cable
.New guidance on cable fixings and accessories.
The new code of practice was published in October 2002 and became effective from July 2003 for new designs. This period was to allow for the necessary training in system design and installation practices and also to allow for the development and approval of new or modified products necessary to meet the new requirements.

However, it is clear that although new products are appearing on the market, there is still much confusion in the market place as to the exact nature of the new requirements and how they can be satisfied.

The new testing requirements for fire resisting cables have received much attention but the new guidance on cable fixings should not be ignored.

Guidance on cable fixings and accessories
BS5839-1:2002 recognizes that methods of cable support should be such that circuit integrity will not be reduced below that afforded by the cable used, and should withstand a similar temperature and duration to that of the cable, whilst maintaining adequate support. In practice this means that fixings for "standard" cables should survive for 30 minutes at a nominal temperature of 850C without loss of integrity and those for "enhanced" cables for 120 minutes at a nominal temperature of 950C.

Plastic cable clips, ties or trunking are therefore noted as not suitable as the sole means of cable support.

The inclusion or trunking illustrates that although plastic trunking may be used for aesthetic or protection reasons, the cable (and trunking) must still be fixed to a suitable non-combustible substrate to meet the requirement of the code of practice.

Whilst these requirements for fixings are consistent with the advice to use proven metal fixings given for many years by major fire resistant cable manufacturers such as Prysmian, there were no specific requirements in earlier editions of BS5839.

Likewise terminals used to joint cables, except those within system components, should be constructed of materials that will withstand a similar temperature and duration to that of the cable. Manufacturers recommendations should be followed, but ceramic rather than plastic terminal blocks will most likely be necessary to fully meet the requirements. Fire resistant junction boxes are already available on the market to meet this requirement.

The need to address the fixings issue was born from problems reported from real fire situations. In one hotel fire investigated by the author, a fire alarm cable had been run from the main building to an annex across a courtyard tied to the bottom of an existing overhead steel cable tray with plastic cable ties. During an incident arising from a fire starting in the courtyard, it was noted that the fire alarm system in the annex had ceased to operate. Upon investigation, it was observed that although the cable tray was still intact, the fire alarm cable was no longer to be seen. It was found on the courtyard floor under various fire debris. The integrity of the whole fire alarm system had been compromised by the use of a few inappropriate fixings.
 12 May 2013 08:27 PM
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slittle

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I'll have a drum in my hands in the morning BOD.

There is normally an odd length on a drum in the truck but it got used last week.

There's 500m on site so if I remember I'll post.


Stu
 12 May 2013 08:51 PM
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dg66

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When i was installing fire alarm systems back in the 80's all our cables were clipped with pvc covered copper P clips every 9 inches.

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

Dave(not Cockburn)
 12 May 2013 09:54 PM
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sparkingchip

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Don't get too focused on fire rated cable. This could be SWA fixed with plastic cable cleats, twin and earth fixed with plastic clips amogst other examples.

If you have some cable running across the top of a doorway or across a ceiling for example that could drop across a passageway or staircase then there is an issue.

What is the advantage of pvc conduit over pvc minitrunking? Do you need to install the pvc conduit with metal saddle clips to gain an advantage?

Andy
 12 May 2013 10:23 PM
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rogersmith7671

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"As most of you will have realised, I enjoy making a daft quip or post on occasion because I have a silly sense of humour.

However I do not think this topic is a joking matter.

But I fail to see that any of the points quoted above are intended to be taken seriously at all."

Oh look a Dalek, or is that a dyslexic?
I see the PM gang came round quick.
 13 May 2013 07:49 AM
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ebee

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rogersmith,
have I misunderstood what you said?
I hope so.

-------------------------
Regards,
Ebee (M I S P N)

Knotted cables cause Lumpy Lektrik
 13 May 2013 09:00 AM
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tomgunn

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Originally posted by: sparkingchip

Reading that through it is easy to see the issue.

In this particular case though it actually reads as it was fire rated cable in PVC mintrunking, so the support and fixing did not match the cable, allowing the cables to drop and get caught between the back of the fire fighters necks and the tanks of the breathing apparatus. But it could happen with any surface mounted cable with supports and fixings that will readily melt in a fire.


This is a dreadful thing that has happened. But, why are you blaming the cable clips? Once the alarm has gone off then thats it - everyone knows theres a fire. What I have read form the inquest mentions that the cables became entangled in the firefighters equipment but this seems something that should have been noted, and trained for before , ( ( b)
Modifying breathing apparatus sets to reduce the risk of cables becoming caught between the wearer's back and the cylinder ((as introduced by Hampshire Fire and Rescue Service - please contact HFRS for more details))): So there have been problems with cables becoming entangled and this was addressed by the Hampshire brigade, so why was it not carried out by the rest of the country?

It seems to me that this inquest is looking for someone else to blame, as they do. Its interesting, actually, my son in laws a fireman up north and I was somewhat surprised to hear that there is no control throughout the country re their equipment as he told me, on several occasions, that each area of firefighting equipment does not fit other areas of firefighting equipment, how weird / outrageous is that?

Once again, yes its sad but I feel its down to training more than anything and it is actually one of their recommendations in the report but I do get the feeling that they are trying to point the blame away from the firefighters, and I know what a difficult and dangerous job they do coupled with the fact that this countries in ruins and Cameron / Boris are trying to reduce the amount of firefighters in London. EVERYTHING is on the cheap, cheap motorway police, cheap navy, ( 2 carriers without planes etc... ), cheap army - its all endemic... part time people cause trouble and this should be amended but that'll cost money and we all understand that its more important to send millions if not billions to other countries in aid!!!

OMS, you ask - 'we never learn do we?' who? The poor people / firefighters on the front line... the poor squadies losing their lives and limbs for absolutely NOTHING in Afghanistan as when its finished in 2014 it'll return to how it was before, probably even worse and without going in too deeply about this disaster and the fact that lives / limbs and families torn apart for nothing, ( mind you - the lucky ones who survive this mess over there will be coming home to get the good olde tin tack! AND, very sorry about this - I watched the man from the government actually say this twice on the BBC news about the injured soldiers returning - and what he said was 'we are not a charity' hows about that!!!!! ), then I would ask this inquest to not look at the cable clips - but perhaps at the government for cuts cuts and even more cuts!!!

I really feel that the problem lies with the government... these people should be given the best training, the best equipment and all of the support from parliament - but it aint gonna happen my fiends as long as 'they' can save a few pounds then that'll do and sod the rest attitude!

Another saying, 'lest we forget'... meaning, learn from the past... invest in our country... train and have the best that we have to serve in all areas and not the cheap will do attitude... well, thats me for the chop!!

Tom

-------------------------
Tom .... ( The TERMINATOR ).

handyTRADESMAN ... haha

Castle Builders

Why did Nick Clegg cross the road? Because he said he wouldn't!

I can resist anything..... except temptation! ( Karl Gunn ).
 13 May 2013 09:30 AM
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normcall

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Like 'dq66', I used to use PVC covered copper 'P' clips for emergency wiring.

Obviously an age thing where practical means more than theory. (Reason I can't pass exams - far too complicated having to think!)

-------------------------
Norman
 13 May 2013 10:27 AM
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sparkingchip

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But if asked to put a emergency light in the middle of a landing ceiling would you think twice about using 1.5mm t&e in pvc minitrunking surface fixed to the ceiling to get to it?

By the time the plastic is melting you or I would be out of the area or incapable of moving far. I assume the issue here is that being flats there could be or was people trapped beyond the fire on the access route so the brigade needed to get past the fire. This is not really about cable clips in ordinary two storey domestic type properties, it is about having a safe means of access to a high multistorey building above the height of ladders and high access equipment that can be used from the exterior of the building.

If you know that a stairway or passageway has to be secure as possible in a fire then cable and clip selection for any surface mounted cable runs has to be appropriate and clearly any type of cable in minitrunking presents a risk as does any type of cable supported with plastic clips.

I'm not convinced changing BS7671 would make much difference though as in this case appropriate regulations had been breached anyway because it did not conform to the regulations already in place.

So it's down to education and training of designers and installers.

Andy
 13 May 2013 11:50 AM
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OMS

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Originally posted by: tomgunn

Originally posted by: sparkingchip

Reading that through it is easy to see the issue.

In this particular case though it actually reads as it was fire rated cable in PVC mintrunking, so the support and fixing did not match the cable, allowing the cables to drop and get caught between the back of the fire fighters necks and the tanks of the breathing apparatus. But it could happen with any surface mounted cable with supports and fixings that will readily melt in a fire.


This is a dreadful thing that has happened. But, why are you blaming the cable clips?

Because they melted and the cables became like the hanging gardens of Babylon - don't you see the risk of that in poor visibility and constrained by BA sets, in an escalating temperature - they were the hazard that trapped FRS personnel.

Once the alarm has gone off then thats it - everyone knows theres a fire.

Really - you of all people know better than that - often we have staged alarms and staged evacuation - and after the alarms are gone off FRS usually need to enter - keep in mind there were persons reported at this incident - so they werer going in regardless.


What I have read form the inquest mentions that the cables became entangled in the firefighters equipment but this seems something that should have been noted, and trained for before ,

Or of course the installer could have understood BS 5839 and acted acordingly - a few metal cored P clips in the minitrunking or a few metal saddles on the PVC conduit would all that was needed.

Modifying breathing apparatus sets to reduce the risk of cables becoming caught between the wearer's back and the cylinder ((as introduced by Hampshire Fire and Rescue Service - please contact HFRS for more details))): So there have been problems with cables becoming entangled and this was addressed by the Hampshire brigade, so why was it not carried out by the rest of the country?

It was - read BS 5839 - I quoted from it above


It seems to me that this inquest is looking for someone else to blame, as they do. Its interesting, actually, my son in laws a fireman up north and I was somewhat surprised to hear that there is no control throughout the country re their equipment as he told me, on several occasions, that each area of firefighting equipment does not fit other areas of firefighting equipment, how weird / outrageous is that?

Are we expecting totally geographically distant brigades to attend the same incident - they will all have issues with dangling cables though

Once again, yes its sad but I feel its down to training more than anything and it is actually one of their recommendations in the report but I do get the feeling that they are trying to point the blame away from the firefighters, and I know what a difficult and dangerous job they do coupled with the fact that this countries in ruins and Cameron / Boris are trying to reduce the amount of firefighters in London. EVERYTHING is on the cheap, cheap motorway police, cheap navy, ( 2 carriers without planes etc... ), cheap army - its all endemic... part time people cause trouble and this should be amended but that'll cost money and we all understand that its more important to send millions if not billions to other countries in aid!!!

Not relevant Tom - it was ***** poor installation practices that caused this


OMS, you ask - 'we never learn do we?' who? The poor people / firefighters on the front line... the poor squadies losing their lives and limbs for absolutely NOTHING in Afghanistan as when its finished in 2014 it'll return to how it was before, probably even worse and without going in too deeply about this disaster and the fact that lives / limbs and families torn apart for nothing, ( mind you - the lucky ones who survive this mess over there will be coming home to get the good olde tin tack! AND, very sorry about this - I watched the man from the government actually say this twice on the BBC news about the injured soldiers returning - and what he said was 'we are not a charity' hows about that!!!!! ),

Don't go there Tom, really - those soldiers are someones son, nephew, cousin, husband, father - you don't need to tell me anything about it, trust me - they are not political footballs.

then I would ask this inquest to not look at the cable clips - but perhaps at the government for cuts cuts and even more cuts!!!

Don't make this a political rant - it was ***** poor installation practices coupled with the usual comprehensive failure of design thinking.


I really feel that the problem lies with the government... these people should be given the best training, the best equipment and all of the support from parliament - but it aint gonna happen my fiends as long as 'they' can save a few pounds then that'll do and sod the rest attitude!

Again, don't circumvent a very inconvenient truth - the Coroner specifically pointed out the issue of cabling - just a few years after the hertfordshire incident.


Another saying, 'lest we forget'... meaning, learn from the past... invest in our country... train and have the best that we have to serve in all areas and not the cheap will do attitude... well, thats me for the chop!!

"Lest we forget" means different things to different people Tom, lets leave it there.

Tom [IMG][/IMG]


regards

OMS

-------------------------
Failure is always an option
IET » Wiring and the regulations » We never learn, do we ?

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