Consumer units -why metal?

[ey143]

What is the reason that consumer units need to be made of metal rather than plastic as they were a few years ago?

 

[EFLImpudence]

'Cos the London Fire Service says so and pitiful capitulation by those who make our rules.

Actually to be precise they must now be made of or enclosed in "non-combustible" material but no one knows what that is so they plumped for steel.

 

[333rocky333]

 

[flameport]

Someone obtained some statistics about an increase in fires involving fuseboxes/consumer units in a certain area of the country over some period of time and then decided that this was entirely due to them being made of plastic.
Therefore it was deemed essential for them to be made of non combustible materials, steel being the cheapest and easiest option.

The actual cause of the fires and whether it started in or was caused by the consumer unit was not considered.
Neither was the fact that plastic consumer units have been routinely installed in their millions for several decades and the apparent increase in fires occurred only recently.
Or the kind of property they were installed in, whether the electrical system had been installed properly, had it been tampered with, inspected recently or at all, etc.

 

[JohnW2]

The actual cause of the fires and whether it started in or was caused by the consumer unit was not considered. .... Neither was the fact that plastic consumer units have been routinely installed in their millions for several decades and the apparent increase in fires occurred only recently. .... Or the kind of property they were installed in, whether the electrical system had been installed properly, had it been tampered with, inspected recently or at all, etc.

Nor was any consideration apparent given to the increased risk of electric shock which presumably arises from surrounding the innards of a CU with earthed metal - at least, in the hands of people who do silly or incautious things (and there are a good few of them around!).

Nor does the regulation, as implemented, make all that much sense. A fire would presumably start within the CU (devices, cables etc.), not by the case itself spontaneously bursting into flames - but there is no requirement for 'fire containment'. It seems that, provided the case is made of the mythical 'non-combustible' material, it can have as many holes in it as IP considerations will allow.

Kind Regards, John

 

[ey143]

If a consumer unit is located in a small cloak room of a size 1m x 2m which also houses a under floor heating manifold, would the heat from the small area have any baring on a risk of fire at a consumer unit on its own?

 

[EFLImpudence]

No.

 

[John D v2.0]

there is no requirement for 'fire containment'. It seems that, provided the case is made of the mythical 'non-combustible' material, it can have as many holes in it as IP considerations will allow.

I think it's basically the 80:20 role at work. There's no need to go straight to perfection. At least now there's less likely bits of melted cu dripping all over whatever people have stored up against their cu.
And actually the IP rating is just for ingress not fire, so you can have a massive hole and just cover it in trunking. But generally it's going to be an improvement on plastic that melts quicker.

 

[Adam_151]

The actual cause of the fires and whether it started in or was caused by the consumer unit was not considered.
Neither was the fact that plastic consumer units have been routinely installed in their millions for several decades and the apparent increase in fires occurred only recently.

But for most of those several decades, the plastic boards have had suitable fire retardants in, so if it gets a bit hot, it melts a little and sooner or later it is smelt and suitably repaired. But not the plastic catches light far too easily, and combined with 5 day wonders changing boards, and then the tails being moved round by the smart meter installer, its a perfect storm

 

[ban-all-sheds]

So yet again we take a sledgehammer to bash out the symptoms of problems which could have been better sorted by addressing the causes - less disruption, less expense, and better results as well.

WTF is wrong with the people running this country?

 

[deadshort]

What is the reason that consumer units need to be made of metal rather than plastic as they were a few years ago?

I think we can thank WYLEX for that,the fires probably had bugger all to do with the tupperware enclosures and more
likely their faulty mcb's.

DS

 

[JohnW2]

I think it's basically the 80:20 role at work. There's no need to go straight to perfection. ...

Yes, but what they actually did is about as far from perfection as one can imagine. The suggestion (the publicised evidence for which appears weak) was that an increasing number of house fires were originating within CUs. If that is what one believes, the the need is for fire containment - which the new reg has not asked for.

And actually the IP rating is just for ingress not fire, so you can have a massive hole and just cover it in trunking ....

I didn't mean to suggest that IP rating had anything to do with fire. My point was that, so long as the CU case (however much of it still existed!) was made of a 'non-combustible' material, it could have as many (uncovered) holes in it (for flames to escape through) as were permissible in terms of Ingress Protection.

Like many others, I am very sceptical of the wisdom of (or need for) this new requirement, for all sort of reasons that we have discussed in the past. Indeed, given that there is also the theoretical downside which I mentioned above, I'm not even convinced that, in the long-term, it will actually result in a net reduction in deaths of serious injuries.

Kind Regards, John

 

[ban-all-sheds]

I'm not even convinced that, in the long-term, it will actually result in a net reduction in deaths of serious injuries.

The people who write the regulations DGAS about that.

 

[JohnW2]

The people who write the regulations DGAS about that.

They presumably must 'care', since otherwise they wouldn't even be bothering to write regulations which are intended to be safety-related. However, it seems that they are 'easily led'/bullied/whatever, not to mention the commercial interests which are represent amongst the 'authors'.

Kind Regards, John

 

[ban-all-sheds]

They presumably must 'care', since otherwise they wouldn't even be bothering to write regulations which are intended to be safety-related.

No - if they really cared then they would do their job properly. Simply doing what someone else tells them will solve a problem without them applying any of their years of experience and training is neither caring nor proper.

However, it seems that they are 'easily led'/bullied/whatever, not to mention the commercial interests which are represent amongst the 'authors'.

No - they just want an easy life.

What kind of engineer, when told that there are a lot of fires originating inside CUs, decides that the way to solve that problem is to make the enclosures "non-combustible" rather than stopping the fires happening in the first place?

What they have done is analogous to the authorities ruling that cars should be rubber-band powered and made out of soft foam as a way to solve the problem of drunk drivers killing and injuring people in crashes.