Metal CU. Why?

[LastManOnline]

Metal CU.

Am curious to know why the UK regs demanded a metal CU. Would it not have been helpful to first investigate what was causing overheating the CU?

 

[ferg]

I think the idea is for the enclosure to not add fuel to any consumer unit fire.

It's all very well pointing the finger at poor workmanship and materials but reality tells us they exist and the metal CU is to mitigate this.

 

[Dartlec]

Metal CU.

Am curious to know why the UK regs demanded a metal CU. Would it not have been helpful to first investigate what was causing overheating the CU?

I think anyone who had ever worked with them knew that it was loose connections in almost all cases.

It seems like it was more the case of - what's a simple solution that we can implement to show we're doing something - possibly with the input of the manufacturers who didn't want to have to do anything costly.

Though in theory the Regs only demand a CU is made of an 'incombustible' material and suggest metal as one option. I assume that steel is just the cheapest way of achieving that.

 

[telectrix]

It seems like it was more the case of - what's a simple solution that we can implement to show we're doing something - possibly with the input of the manufacturers who didn't want to have to do anything costly.

WINNER.

 

[James]

Asbestos is non combustible, I think it might come back in to fashion.

 

[LastManOnline]

Metal CU.

Am curious to know why the UK regs demanded a metal CU. Would it not have been helpful to first investigate what was causing overheating the CU?

But back to my original question. WHY the change?. WHAT exactly was the reasoning behind the necessity to change from pvc to metal?

 

[telectrix]

because the London Fire Brigade attributed several fires as originating from inside Consumer Units. rather than address the cause of poor installation practice and possibly cheap shoddy components, it was decided by the suits that it was a good idea to allow the CU fires to continue but encase them in a metal box to stop the fire spreading to granny's inflammable underwear on a clothes horse under the stairs in front of the CU.

 

[Dartlec]

But back to my original question. WHY the change?. WHAT exactly was the reasoning behind the necessity to change from pvc to metal?

I believe it was input from the fire brigade on the number of fires being caused, but I'm not sure what evidence they had that plastic was the main problem...

 

[LastManOnline]

But back to my original question. WHY the change?. WHAT exactly was the reasoning behind the necessity to change from pvc to metal?

Should have said that they were considering making the same change here (ROI) where we often "copy and paste" UK regs. Curiously they passed on this one. I agree as I have never experienced a fire at a CU (DB.) I have the same uneasy feelings about this one as, I have about AFDD, s.

 

[Lucien Nunes]

I recall that some CUs were tested and the plastic casing was found to be made from material that was not correctly self-extinguishing. Whilst one would hope that no part of a CU would ever ignite, nonetheless there are components inside that could be expected to arc violently in the event of a catastrophic fault. So there is a certain login in not wanting those components to be housed in a flammable box, which is what some cheap plastic CUs turned out to be. 100 years ago, it was accepted that while an asbestos-lined wooden box was attractive, cast-iron switchgear with porcelain insulators, i.e. completely non-combustible materials throughout, was less of a fire risk.

 

[Dartlec]

I recall that some CUs were tested and the plastic casing was found to be made from material that was not correctly self-extinguishing. Whilst one would hope that no part of a CU would ever ignite, nonetheless there are components inside that could be expected to arc violently in the event of a catastrophic fault. So there is a certain login in not wanting those components to be housed in a flammable box, which is what some cheap plastic CUs turned out to be.

Sounds like they might have been better specifying a proper standard for self-extinguishing plastic then?

It would be interesting to know if they properly assessed the risk of metal enclosures (in TT installations particularly) being properly earthed, vs the advantages of metal.

 

[LastManOnline]

I recall that some CUs were tested and the plastic casing was found to be made from material that was not correctly self-extinguishing. Whilst one would hope that no part of a CU would ever ignite, nonetheless there are components inside that could be expected to arc violently in the event of a catastrophic fault. So there is a certain login in not wanting those components to be housed in a flammable box, which is what some cheap plastic CUs turned out to be.

I ca

I recall that some CUs were tested and the plastic casing was found to be made from material that was not correctly self-extinguishing. Whilst one would hope that no part of a CU would ever ignite, nonetheless there are components inside that could be expected to arc violently in the event of a catastrophic fault. So there is a certain login in not wanting those components to be housed in a flammable box, which is what some cheap plastic CUs turned out to be. 100 years ago, it was accepted that while an asbestos-lined wooden box was attractive, cast-iron switchgear with porcelain insulators, i.e. completely non-combustible materials throughout, was less of a fire risk.

Appreciate that but I personally have NEVER experienced a fire at a DB (CU). What is, occurring in the UK that makes, it implement these, measures? What makes the UK situation more vulnerable to fires?

 

[Dartlec]

Appreciate that but I personally have NEVER experienced a fire at a DB (CU). What is, occurring in the UK that makes, it implement these, measures? What makes the UK situation more vulnerable to fires?

At a guess, screwfix £50 boards being thrown onto the wall by people who don't know what torque is?

Not sure if that's an issue in the same way over there?

 

[LastManOnline]

At a guess, screwfix £50 boards being thrown onto the wall by people who don't know what torque is?

Not sure if that's an issue in the same way over there?

It's not just against regulations but it's actually against the law over here for a layperson to install a CU. In fact it is now against the law for a qualified electrician to take the cover off a CU in a domestic installation unless he is a registered contractor as well as been a conventionally trained electrician. A little OTT I know but that's where we are at the Mo.

 

[Dartlec]

It's not just against regulations but it's actually against the law over here for a layperson to install a CU. In fact it is now against the law for a qualified electrician to take the cover off a CU in a domestic installation unless he is a registered contractor as well as been a conventionally trained electrician. A little OTT I know but that's where we are at the Mo.

Interesting - not sure that would go down well here Though I guess it would be consistent with Gas Regs. But pointless if it's not enforced anyway...

 

[westward10]

It's not just against regulations but it's actually against the law over here for a layperson to install a CU. In fact it is now against the law for a qualified electrician to take the cover off a CU in a domestic installation unless he is a registered contractor as well as been a conventionally trained electrician. A little OTT I know but that's where we are at the Mo.

Are you an REC.

 

[LastManOnline]

Interesting - not sure that would go down well here Though I guess it would be consistent with Gas Regs. But pointless if it's not enforced anyway...

it is been strictly enforced here.My inspector (we currently get 1 inspection a year) has made a point in recent years of highlighting the number of people fined or jailed for contravening the law (previously known as "the regs").
Anyway here's a thought regarding my original question. There are many foreigners in my area with homes, some resident, some holiday. I notice that those most likely to carry out their own electricial work are from UK. I wondered could this be a factor in your issues with CU fires?.
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Are you an REC.

Yes

 

[pc1966]

I notice that those most likely to carry out their own electricial work are from UK. I wondered could this be a factor in your issues with CU fires?.

I'm not sure there has been a massive increase in DIY activity for CUs to explain fire matters in recent years.

While you see a few pop up here asking for advice, I suspect the main issue for CU fires has been "professionals" who are useless at electrics. Not just the builders & plumbers who have a go and get berated here, but also a general de-skiling of the trade due to the loss of apprenticeships and the pressure to get qualifications in a few week's worth of a course.

While I am in favour of torque screwdrivers (on the same principle that I would always use a torque wrench for doing a cylinder head, etc) the recent increase in that aspect is probably also down to poorer skills/experience, and maybe poorer products with less tolerance to tightening effort, all down to the same issue.

 

[LastManOnline]

I'm not sure there has been a massive increase in DIY activity for CUs to explain fire matters in recent years.

While you see a few pop up here asking for advice, I suspect the main issue for CU fires has been "professionals" who are useless at electrics. Not just the builders & plumbers who have a go and get berated here, but also a general de-skiling of the trade due to the loss of apprenticeships and the pressure to get qualifications in a few week's worth of a course.

While I am in favour of torque screwdrivers (on the same principle that I would always use a torque wrench for doing a cylinder head, etc) the recent increase in that aspect is probably also down to poorer skills/experience, and maybe poorer products with less tolerance to tightening effort, all down to the same issue.

That is certainly an interesting point about the de-skilling taking place in the trade. I was, nt aware of that. What was the general reaction to the introduction of the metal CU like among sparks in general.? After all, working with metal is usually more labour intensive than plastic

 

[telectrix]

it's aknown fact that if Fire Brigade can't determine the cause of a fire, it's always put down as an electrical fault.

 

[pc1966]

I think it is true that there are a lot of fires that are electrically started, but I also suspect the majority are not due to fixed building wiring but are defective appliances.

For example, it was a fridge-freezer that started the Genfell fire, the worst in UK recent history. But the main reasons that led to such a great loss of life was lax building standards and, to a some degree, various issues relating to fire-fighting. But usually it is things like tumble dryers that are more common fire hazards it seems.

I can't speak for others but I am in favor of metal CU, it just seems sensible to have something that is reasonably tough and fire-resistant even if the risk from a well-fitted CU is negligible. But as mentioned, a decent grade of plastic that meets fire containment and LSOF behavior would be fine as well.

Perhaps they don't trust industry and/or cheap imports to keep meeting a specific grade of plastic, but "is it metal?" is harder to dodge. Who knows?

 

[StephenRowley]

Is it really that more taxing to install a metal CU than plastic enough to actually worry too mcuh about the requirements for the CU to metal?

 

[LastManOnline]

I think it is true that there are a lot of fires that are electrically started, but I also suspect the majority are not due to fixed building wiring but are defective appliances.

For example, it was a fridge-freezer that started the Genfell fire, the worst in UK recent history. But the main reasons that led to such a great loss of life was lax building standards and, to a some degree, various issues relating to fire-fighting. But usually it is things like tumble dryers that are more common fire hazards it seems.

I can't speak for others but I am in favor of metal CU, it just seems sensible to have something that is reasonably tough and fire-resistant even if the risk from a well-fitted CU is negligible. But as mentioned, a decent grade of plastic that meets fire containment and LSOF behavior would be fine as well.

Perhaps they don't trust industry and/or cheap imports to keep meeting a specific grade of plastic, but "is it metal?" is harder to dodge. Who knows?

I think it is true that there are a lot of fires that are electrically started, but I also suspect the majority are not due to fixed building wiring but are defective appliances.

Agree 100% on this point about the fixed wiring not been the origin of electrical fires. Statistics on this one not easy to come by. Secondly I would have no objection to installing metal CU, s in domestic installs providing there are sound and justifiable reasons for doing so. I struggle a little with the concept of having to adjust the materials because of poor installation skills on the part of untrained/semi trained personnel. I would prefer if the issue was approached from the direction of upskilling the personell

 

[StephenRowley]

I don't think it's necessary because of them expecting poor workmanship. It's just an additional safety precaution in case someone does make a slip up nobody's prefect, although it may have been overly cautious.

What's that old saying "if you haven't done anything wrong you haven't done anything"

 

[Dustydazzler]

it's aknown fact that if Fire Brigade can't determine the cause of a fire, it's always put down as an electrical fault.

I suppose years ago it could have been attributed to old Doris falling asleep with a lit cigarette in her mouth , but hardly anyone smokes these days so Cigarette fires must be on the fall...

 

[James]

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!

 

[Pete999]

Metal CU.

Am curious to know why the UK regs demanded a metal CU. Would it not have been helpful to first investigate what was causing overheating the CU?

Question What are Junior and Senior Trades qualifications issued in IRELAND? out of interest
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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!

Seen a few that need covering up though

 

[LastManOnline]

Question What are Junior and Senior Trades qualifications issued in IRELAND? out of interest
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Seen a few that need covering up though

I assume you meant When they are issued? If nothing has changed since I came out of my time, than junior trades after 2 years and senior trades on year 4.Some sparks would then simultaneously do the C&G equivalent

 

[Pete999]

I assume you meant When they are issued? If nothing has changed since I came out of my time, than junior trades after 2 years and senior trades on year 4.Some sparks would then simultaneously do the C&G equivalent

Thanks Ed, but what exactly are the two Quals, Junior and senior what do they equate to? City and Guilds wise
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I assume you meant When they are issued? If nothing has changed since I came out of my time, than junior trades after 2 years and senior trades on year 4.Some sparks would then simultaneously do the C&G equivalent

OK but what are the CnG equivalent? not an unreasonable question I think.

 

[LastManOnline]

Thanks Ed, but what exactly are the two Quals, Junior and senior what do they equate to? City and Guilds wise
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OK but what are the CnG equivalent?

Apologies. I don't believe the Junior trades has an equivalent in The UK. The Senior trades used to be equivalent to the C&G course B. That's how it was in my time. (For "my time" read "old fogies")