Metal CU. Why?

[pc1966]

Unfortunately that final link did'nt work. Looks interesting. As, firemen are obviously on the front line and have firsthand experience of the real issues

This forum borks links to the IET site for reasons that are not obvious. However, the important bits from the article (to me at least) are quoted below:

Fires in plastic consumer units - a pattern of fires emerges

Back in 2011, the Fire Investigation Team identified an increase in the number and severity of fires involving consumer units. The team started looking carefully at the cause of those fires and established that there were issues with high resistance connections, where cables were not secured properly. This had the potential to lead to localised heating, arcing and, in some cases, to fires. There was also an emerging problem due to a large batch (over 1 million units) of non-compliant miniature circuit breakers (MCBs), which were subject to a product recall and which could also fail catastrophically.

Severe fires

The team were also seeing more fires that were spreading beyond the consumer unit and putting people’s lives at risk. Through a careful process of laboratory examinations and tests at Brigade consultant scientists Bureau Veritas, concern was raised about the flammability of the plastic enclosures of consumer units. Working closely with Electrical Safety First, more extensive tests of five plastic consumer units from different manufactures were carried out in 2012. These tests gave significant cause for concern due to the intensity of the fire and the levels of toxic smoke produced.

Location, location, location

A significant cause for concern when a consumer unit becomes involved in a fire is that it is commonly located on an escape route, for example, under the stairs or behind the front door. When this is combined with the fairly usual situation of coats, outdoor wear and other household items being stored nearby, once the fire starts, it often develops very quickly. London Fire Brigade was becoming extremely alarmed at the number of injuries occurring at such fires and the need for people to be rescued as they became trapped when the escape route was involved in fire.

A way forward

Working with Electrical Safety First, industry body BEAMA and other stakeholders, the process of presenting evidence for change began. A JPEL/64 project group was set up and ‘robust’ discussions about possible changes to BS 7671 (the Wiring Regulations) continued over several months.

Representatives from the Department of Communities and Local Government (DCLG) attended and raised concerns about possible changes. As a result of these concerns, DCLG commissioned independent tests at the Building Research Establishment (BRE). BRE tested two plastic and two metal consumer units and the subsequent report appeared to strongly support the need for change, stating:

“Both plastic consumer units caught fire and their casings became involved in the fire”… … “Both metal consumer units contained the fire within the unit” (Source: BRE report BD2890)

Also, some manufacturers ran their own tests, the outcomes of which again demonstrated the need for change. This led to a new regulation to be included in Amendment No. 3 to BS 7671, effectively requiring consumer unit enclosures in domestic households to be manufactured from non-combustible material (such as steel) or to be enclosed in a cabinet or enclosure constructed of non-combustible material. This new regulation is a welcomed step-change improvement in fire safety.

 

[LastManOnline]

This forum borks links to the IET site for reasons that are not obvious. However, the important bits from the article (to me at least) are quoted below:

Fires in plastic consumer units - a pattern of fires emerges

Back in 2011, the Fire Investigation Team identified an increase in the number and severity of fires involving consumer units. The team started looking carefully at the cause of those fires and established that there were issues with high resistance connections, where cables were not secured properly. This had the potential to lead to localised heating, arcing and, in some cases, to fires. There was also an emerging problem due to a large batch (over 1 million units) of non-compliant miniature circuit breakers (MCBs), which were subject to a product recall and which could also fail catastrophically.

Severe fires

The team were also seeing more fires that were spreading beyond the consumer unit and putting people’s lives at risk. Through a careful process of laboratory examinations and tests at Brigade consultant scientists Bureau Veritas, concern was raised about the flammability of the plastic enclosures of consumer units. Working closely with Electrical Safety First, more extensive tests of five plastic consumer units from different manufactures were carried out in 2012. These tests gave significant cause for concern due to the intensity of the fire and the levels of toxic smoke produced.

Location, location, location

A significant cause for concern when a consumer unit becomes involved in a fire is that it is commonly located on an escape route, for example, under the stairs or behind the front door. When this is combined with the fairly usual situation of coats, outdoor wear and other household items being stored nearby, once the fire starts, it often develops very quickly. London Fire Brigade was becoming extremely alarmed at the number of injuries occurring at such fires and the need for people to be rescued as they became trapped when the escape route was involved in fire.

A way forward

Working with Electrical Safety First, industry body BEAMA and other stakeholders, the process of presenting evidence for change began. A JPEL/64 project group was set up and ‘robust’ discussions about possible changes to BS 7671 (the Wiring Regulations) continued over several months.

Representatives from the Department of Communities and Local Government (DCLG) attended and raised concerns about possible changes. As a result of these concerns, DCLG commissioned independent tests at the Building Research Establishment (BRE). BRE tested two plastic and two metal consumer units and the subsequent report appeared to strongly support the need for change, stating:

“Both plastic consumer units caught fire and their casings became involved in the fire”… … “Both metal consumer units contained the fire within the unit” (Source: BRE report BD2890)

Also, some manufacturers ran their own tests, the outcomes of which again demonstrated the need for change. This led to a new regulation to be included in Amendment No. 3 to BS 7671, effectively requiring consumer unit enclosures in domestic households to be manufactured from non-combustible material (such as steel) or to be enclosed in a cabinet or enclosure constructed of non-combustible material. This new regulation is a welcomed step-change improvement in fire safety.

Many thanks for posting that info

 

[pc1966]

Many thanks for posting that info

No problem!

The article also mentioned the changes to have fire-resistant support for cables due to deaths of firefighters entangled in dropped cables, another Amendment 3 aspect, but as this thread is about metal CU I left that out.

 

[LastManOnline]

No problem!

The article also mentioned the changes to have fire-resistant support for cables due to deaths of firefighters entangled in dropped cables, another Amendment 3 aspect, but as this thread is about metal CU I left that out.

That's a pretty conclusive read. Interesting that the main issues are 1) loose connections (expected that) and ( 2) substandard materials like mcb, s (did, nt expect that)

 

[DPG]

That's a pretty conclusive read. Interesting that the main issues are 1) loose connections (expected that) and ( 2) substandard materials like mcb, s (did, nt expect that)

Yes there was a major problem with a batch of MCBs which were recalled. Very embarrassing for a major manufacturer. There will no doubt still be a lot out there.

 

[nicebutdim]

This forum borks links to the IET site for reasons that are not obvious. However, the important bits from the article (to me at least) are quoted below:

Fires in plastic consumer units - a pattern of fires emerges

Back in 2011, the Fire Investigation Team identified an increase in the number and severity of fires involving consumer units. The team started looking carefully at the cause of those fires and established that there were issues with high resistance connections, where cables were not secured properly. This had the potential to lead to localised heating, arcing and, in some cases, to fires. There was also an emerging problem due to a large batch (over 1 million units) of non-compliant miniature circuit breakers (MCBs), which were subject to a product recall and which could also fail catastrophically.

Severe fires

The team were also seeing more fires that were spreading beyond the consumer unit and putting people’s lives at risk. Through a careful process of laboratory examinations and tests at Brigade consultant scientists Bureau Veritas, concern was raised about the flammability of the plastic enclosures of consumer units. Working closely with Electrical Safety First, more extensive tests of five plastic consumer units from different manufactures were carried out in 2012. These tests gave significant cause for concern due to the intensity of the fire and the levels of toxic smoke produced.

Location, location, location

A significant cause for concern when a consumer unit becomes involved in a fire is that it is commonly located on an escape route, for example, under the stairs or behind the front door. When this is combined with the fairly usual situation of coats, outdoor wear and other household items being stored nearby, once the fire starts, it often develops very quickly. London Fire Brigade was becoming extremely alarmed at the number of injuries occurring at such fires and the need for people to be rescued as they became trapped when the escape route was involved in fire.

A way forward

Working with Electrical Safety First, industry body BEAMA and other stakeholders, the process of presenting evidence for change began. A JPEL/64 project group was set up and ‘robust’ discussions about possible changes to BS 7671 (the Wiring Regulations) continued over several months.

Representatives from the Department of Communities and Local Government (DCLG) attended and raised concerns about possible changes. As a result of these concerns, DCLG commissioned independent tests at the Building Research Establishment (BRE). BRE tested two plastic and two metal consumer units and the subsequent report appeared to strongly support the need for change, stating:

“Both plastic consumer units caught fire and their casings became involved in the fire”… … “Both metal consumer units contained the fire within the unit” (Source: BRE report BD2890)

Also, some manufacturers ran their own tests, the outcomes of which again demonstrated the need for change. This led to a new regulation to be included in Amendment No. 3 to BS 7671, effectively requiring consumer unit enclosures in domestic households to be manufactured from non-combustible material (such as steel) or to be enclosed in a cabinet or enclosure constructed of non-combustible material. This new regulation is a welcomed step-change improvement in fire safety.

When you think about it, plastic was an odd choice of material in the first instance. Other than being non-conductive I can't think of many reasons why it might have been used, other than cost. While safely installed distribution boards shouldn't be a fire risk, the fact is that this risk exists.

One thing that stuck me while reading through this thread is the aesthetic issue. Yeah I know it wont be of great importance to most electricians, but it would be a source of annoyance for many home owners (not going to be sexist and say women). Old metal BS3036 boards from the 70s or 80s generally look as good as the day they were installed, although a bit dated, but 90s plastic units are often yellowed with age and can look a bit manky and I reckon the current crop of boards should be less contentious for decor conscious homeowners.

There are probably plastics in existence that are considered to be non-combustible and which don't emit toxic fumes when heated, but I'm not aware of any manufacturer that tried this route. Bakelite would be a suitable choice, but I doubt many people would want to work with it!

 

[Dustydazzler]

Wouldn’t it be nice if you could get consumer units made of glass or other transparent non flammable material?

Might force a bit more pride in some people’s work.

There have been a few installations posted on here that look so good it is almost a crime to cover them up!

just leave the lid off ...

 

[DPG]

When you think about it, plastic was an odd choice of material in the first instance. Other than being non-conductive I can't think of many reasons why it might have been used, other than cost. While safely installed distribution boards shouldn't be a fire risk, the fact is that this risk exists.

One thing that stuck me while reading through this thread is the aesthetic issue. Yeah I know it wont be of great importance to most electricians, but it would be a source of annoyance for many home owners (not going to be sexist and say women). Old metal BS3036 boards from the 70s or 80s generally look as good as the day they were installed, although a bit dated, but 90s plastic units are often yellowed with age and can look a bit manky and I reckon the current crop of boards should be less contentious for decor conscious homeowners.

There are probably plastics in existence that are considered to be non-combustible and which don't emit toxic fumes when heated, but I'm not aware of any manufacturer that tried this route. Bakelite would be a suitable choice, but I doubt many people would want to work with it!

The yellowing is a good point. Early UPVC doors had the same problem. No excuse for it these days really, if good quality materials are used. Showers often seem to have the problem though.

 

[nicebutdim]

The yellowing is a good point. Early UPVC doors had the same problem. No excuse for it these days really, if good quality materials are used. Showers often seem to have the problem though.

I don't get to see many examples up close, but one other question in my mind was whether plastic units tend to become brittle or fragile with the passing of time?

 

[stewartrossinv]

It is through the in-depth investigations conducted by fire investigation teams after major fires that causal patterns in what are still relatively rare fires are discovered. London Fire Brigade is the largest in the UK (Scottish Fire and Rescue the second-largest), and its fire investigation teams found and drew national attention to the problems with fridge freezers and so on as already mentioned. I have no doubt that the issues they found are real.

In 2018-19 there were 11 deaths associated with a source of ignition being categorised as 'electrical distribution' out of a total of 164 fatalities in accidental dwelling fires in England (from data recorded on the national Incident Recording System and published annually by the Home Office, available at Fire statistics - https://www.gov.uk/government/collections/fire-statistics). It is not possible to know from the published information how many of these deaths resulted from overheating in consumer units, if any, or from wiring, trailing leads and other sources in the domestic environment. The details gathered by fire investigation teams in general remain confidential as in some cases investigations can result in legal action being taken.

The misuse of smokers materials accounted for 55 accidental dwelling fire deaths in England in 2018-19, so smoking remains a major cause of fire deaths.

I am not in any way doubting the importance of the contribution to fire safety that metal consumer units can and do make. To give just one example of the importance of legislative change in saving lives in fires, the change to the composition of furnishings in the 1980s (with the requirement for fire-retardant fillings and so on) has contributed to ongoing reductions in fire deaths and is responsible for saving hundreds of lives in the years that have passed. That along with the mandatory adoption of mains-powered smoke detection, which gives due warning of a fire to allow for escape from what otherwise could be fatal circumstances. When properties are protected by battery-powered smoke alarms it is heartbreaking for crews to find after a fire that the batteries were disconnected...

 

[ipf]

This forum borks links to the IET site for reasons that are not obvious. However, the important bits from the article (to me at least) are quoted below:

Fires in plastic consumer units - a pattern of fires emerges

Back in 2011, the Fire Investigation Team identified an increase in the number and severity of fires involving consumer units. The team started looking carefully at the cause of those fires and established that there were issues with high resistance connections, where cables were not secured properly. This had the potential to lead to localised heating, arcing and, in some cases, to fires. There was also an emerging problem due to a large batch (over 1 million units) of non-compliant miniature circuit breakers (MCBs), which were subject to a product recall and which could also fail catastrophically.

Severe fires

The team were also seeing more fires that were spreading beyond the consumer unit and putting people’s lives at risk. Through a careful process of laboratory examinations and tests at Brigade consultant scientists Bureau Veritas, concern was raised about the flammability of the plastic enclosures of consumer units. Working closely with Electrical Safety First, more extensive tests of five plastic consumer units from different manufactures were carried out in 2012. These tests gave significant cause for concern due to the intensity of the fire and the levels of toxic smoke produced.

Location, location, location

A significant cause for concern when a consumer unit becomes involved in a fire is that it is commonly located on an escape route, for example, under the stairs or behind the front door. When this is combined with the fairly usual situation of coats, outdoor wear and other household items being stored nearby, once the fire starts, it often develops very quickly. London Fire Brigade was becoming extremely alarmed at the number of injuries occurring at such fires and the need for people to be rescued as they became trapped when the escape route was involved in fire.

A way forward

Working with Electrical Safety First, industry body BEAMA and other stakeholders, the process of presenting evidence for change began. A JPEL/64 project group was set up and ‘robust’ discussions about possible changes to BS 7671 (the Wiring Regulations) continued over several months.

Representatives from the Department of Communities and Local Government (DCLG) attended and raised concerns about possible changes. As a result of these concerns, DCLG commissioned independent tests at the Building Research Establishment (BRE). BRE tested two plastic and two metal consumer units and the subsequent report appeared to strongly support the need for change, stating:

“Both plastic consumer units caught fire and their casings became involved in the fire”… … “Both metal consumer units contained the fire within the unit” (Source: BRE report BD2890)

Also, some manufacturers ran their own tests, the outcomes of which again demonstrated the need for change. This led to a new regulation to be included in Amendment No. 3 to BS 7671, effectively requiring consumer unit enclosures in domestic households to be manufactured from non-combustible material (such as steel) or to be enclosed in a cabinet or enclosure constructed of non-combustible material. This new regulation is a welcomed step-change improvement in fire safety.

Correct, and we (mostly) know it makes a lot of sense.
Standards of materials used is so important. As an example, we see old Wylex CU's in such a mess, including photos on here. Cables sizes, fusing of all types and sizes, earthing and all sorts of mix ups.
We miss one point though, why did they last so long, faults or not, without CU fire problems?
OK, we have rcd protection and other plusses, but for me....the class and solidarity of connections, along with simplicity of design made such a difference.
Now, we get onto circuit breakers. Some of the designs and connections are pathetic and who gives a damn if someone sticks all sorts of different make breakers in a board?
Then we get some idiots who can't, or don't, even fit a tiny busbar correctly.
The list goes on.......

 

[Midwest]

Unfortunately that final link did, nt work. Looks interesting. As, firemen are obviously on the front line and have firsthand experience of the real issues

I'll try again. IET Link

Given up. Just Google 'IET why were metal consumer unit introduced'. Hopefully you'll find the piece, 3 places down. Its headed '55 - Special Edition II 2015'. Going for a lie down now.

 

[DPG]

I'll try again. IET Link

I'd give up

 

[Pete999]

Here’s a couple of links from Electrical Safety First, a charity organisation in UK, and the IET, with their views on the subject, FYI @Edmond Noonan. There’s various others that give the reasoning, or context if you will.

https://www.electricalsafetyfirst.org.uk/media/1258/consumer-unit-connections.pdf

Consumer Unit Mythbuster | Electrical Safety First

Consumer Unit Mythbuster From 1st January, consumer units and similar switchgear assemblies installed in domestic premises must either have their enclosure cons

www.electricalsafetyfirst.org.uk

https://electrical.------.org/wirin...tection-against-fire-the-fire-officer-s-view/

Here’s a couple of links from Electrical Safety First, a charity organisation in UK, and the IET, with their views on the subject, FYI @Edmond Noonan. There’s various others that give the reasoning, or context if you will.

https://www.electricalsafetyfirst.org.uk/media/1258/consumer-unit-connections.pdf

Consumer Unit Mythbuster | Electrical Safety First

Consumer Unit Mythbuster From 1st January, consumer units and similar switchgear assemblies installed in domestic premises must either have their enclosure cons

www.electricalsafetyfirst.org.uk

https://electrical.------.org/wirin...tection-against-fire-the-fire-officer-s-view/

Or maybe upgrade the training for DIs, poor training has to be a factor in thid

I'll try again. IET Link

Given up. Just Google 'IET why were metal consumer unit introduced'. Hopefully you'll find the piece, 3 places down. Its headed '55 - Special Edition II 2015'. Going for a lie down now.

Question I have always wanted to ask , but was afraid of repercussions, was or is it something to do with "boil in the bag Electricians being Qualified and able to join CP schemes"? just a question nothing else.

 

[DPG]

Or maybe upgrade the training for DIs, poor training has to be a factor in thid

Question I have always wanted to ask , but was afraid of repercussions, was or is it something to do with "boil in the bag Electricians being Qualified and able to join CP schemes"? just a question nothing else.

Pete, you do tend to go on about this issue.

 

[Pete999]

Pete, you do tend to go on about this issue.

Yes I do don't I quite right too. I thought that' why we fight all theses Wars for, free speech and free expression of our opinions, until the issue of boil in the bag Sparkles exist I will continue to campaign for proper Apprenticeships and abolish the quick fix issue cus that;s all it is a "quick fix"

 

[telectrix]

it's not just short course DI's, it's DIYers, builders, kitchen fitters, and also a proportion of time served sparks, ad. nauseam. blame is on poor training (or lack of any training) no matter who done it.

 

[Pete999]

it's not just short course DI's, it's DIYers, builders, kitchen fitters, and also a proportion of time served sparks, ad. nauseam. blame is on poor training (or lack of any training) no matter who done it.

Well said Tel

 

[telectrix]

thing is, us old school know that after tightening a terminal, we let it rest for a few minutes, wriggle it, then tighten again. bet this ain't taught on the 5week courses for one.

 

[Pete999]

it's not just short course DI's, it's DIYers, builders, kitchen fitters, and also a proportion of time served sparks, ad. nauseam. blame is on poor training (or lack of any training) no matter who done it.

Agree Tel but some can bang on about it, the Establishment will not waiver, too much cash involved I'm afraid, to many fingers in the pies.