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?.
[automerge]1601326578[/automerge]

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.