To JP -

I apologise if I have personally offended you in some way. I get exasperated with the changes to the wiring regulations where a cynic might rightfully suggest that some such changes appear to be driven in pursuit of profit rather than enhanced safety. Take arc fault protection devices for example, which from what I have gathered, do not actually work, other than to enhance the bottom lines of the vendors. Surge protection devices are another example, a couple of jelly bean components in a plastic enclosure which may or may not function, yet priced more expansively than saffron on a per-gram bases. Where are these surges emanating from? Supply-side switching rather than customer side?


As for LFB lobbying the IET for metal consumer units, it would have been much simpler if the IET/JPL et al had conducted some independent studies of their own.

A far better and more pragmatic solution might have been to specify non-flammable consumer units where the mains supply intake is situated under a wooden staircase, which is especially common in terraces.

This would have made sense and would have added a little more credence to the argument, since a staircase is an escape route.

One thing I never found was any evidence where a fire was started as a consequence of maintenance neglect of the supplier's equipment.

Was there no evidence available as to how many badly maintained supply intakes had been the root cause of at least some of these fires?

Why were consumer units on the customer side targeted instead?

I hope you can now begin to see why I posted what I did - and when you look at the make-up of the wiring regs committee you can see why one might wonder as to how and why some of the changes are driven.

I support the IET, or rather, supported the IEE as was, but I do struggle to muster up enthusiasm for an organisation which appears to do itself no favours when it comes to it's own reputation, but then again, I suppose that's my problem again, after all, I am but a mere consumer.

In the times we live in now professional organisations like the IET and UKPN/DNOs find themselves stuck between a rock and a hard place in as much as whatever rules they make will be scrutinised hard by engineering folk like us here and lawyers  so one tiny mistake and the legal people will be all over it like a rash  so I have some sympathy with professional bodies these days of litigation make it hard to make big decisions for fear of trouble later on. Now I agree that metal CUs mite have benefitted from more discussion and research BUT as I said the decision made mite of been partly made out of fear for want of a better word

There will be plenty of comparison data from other countries as almost nowhere else on the planet considers a plastic enclosure for electricity to be a bad idea.

On the other hand, not many other countries try stuffing 7-strand 25mm² into shallow cage clamp terminals or draw up to 100A/phase for domestics.

 

Use a BG consumer unit with an IP rated aluminium enclosure. 

Interesting - is that a CU with an aluminium case, or a plastic CU in an additional aluminium enclosure? Either way, it seems a little suspect - aluminium has a much lower melting point than steel (I've melted drinks cans in a simple bonfire - steel food cans survive pretty much intact) - and BS 7671 only reference to the required performance is to ferrous metal.

at the request of the London Fire Service who made their case to JPEL due to the number of fires they were attending involving consumer units. 

I still wonder if it might have been more appropriate to lobby the committee behind BS EN 61439 rather than BS 7671.


   - Andy.

Indeed, and if the fires and accidents remain at comparable rates even after the change of CU, that would indicate perhaps we should look at other variations such as meter tail terminations and other measures.

Further to my last,

Lawyers and the threats of litigation should not be permitted to dictate how the laws of physics are applied!

Therin lies the rub. It is as if the whole pyramid of responsibility is being inverted whereby the Little Man is at the pointy end and being made responsible for items and activities way beyond his control.

Take for example, the requirement to report upon the state of the DNO's equipment when issuing certification. Why did the IET allow this?

The certification requests information on the type and rating of the main supply fuse(s), yet this information can only be obtained by breaking the cut-out seals (and potentially the law), withdrawing the fuse and copying down the details.

Also, why has a heading entitled 'Risk Assessment Y/N appeared on the forms? Risk assess what exactly? Continued use of the installation as is?

Sorry if I am on a rant,

Also, why has a heading entitled 'Risk Assessment Y/N appeared on the forms?

Where's that? (and is that on BS 7671 forms, or some club's bespoke ones?)


I might guess it's asking about the risk assessment that's need to omit 30mA RCD protection from socket outlets by 411.3.3 - but that that's a complete guess and could be way out...


  - Andy.

In the model form, in the section "Details of departures from BS 7671", it has "Details of permitted exceptions (Regulation 411.3.3). Where applicable, a suitable risk assessment(s) must be attached to this Certificate".


411.3.3 is about needing a risk assessment for omitting an RCD.

whjohnson:

. . . Was there no evidence available as to how many badly maintained supply intakes had been the root cause of at least some of these fires? . . . 

• It has (or should have) given the opportunity to ensure that every installation was sealed correctly, as every installation has to be visited as part of the project. 

• “Supply Fail” and “Meter Terminal Cover Removed” are just two of the standard alarms sent by every smart meter. As the smart meter was sealed correctly on installation, these alarms can give clues to interference with the cutout and / or metering equipment, which the DNO / Meter Operator should be following up. 

Regards,


Alan.

The thing is Alan, as far as I am aware, there is no proactive maintenance regime in place for the regular inspection of a suppliers equipment.

Smart meters may well tell tales, but they won't cure a loose and overheating connection inside the meter itself, nor the cutout.

The simplest cure-all when it comes to minimising interfering with meters is the fitting of a simple £10 isolator, then there's no excuse, and the switch provides a single point of isolation for all to use.

Add to this the confusion as to who exactly is responsible for such equipment and it is a recipe for blame deflection which ends up going round in perpetual circles, with regular choruses of "Not ours mate, not ours".

How does that assist the consumer and the likes of the LFB when it comes to fire prevention and locating the root cause of a fire?

“there is no proactive maintenance regime in place for the regular inspection of a suppliers equipment.”

That is a question for the appropriate DNO / Meter Operator. We have a regime in place, allied to meter readings, and will still have a regime in place once smart meters are installed. 


“Smart meters may well tell tales, but they won't cure a loose and overheating connection inside the meter itself, nor the cutout.”

No, but it should show if there is a problem, whether the issue is related to the meter installation (which would be concerning), or the butchering of seals by others. 


“Add to this the confusion as to who exactly is responsible for such equipment” 

There is no confusion in the legislation. The DNO owns the cutout, the Meter Operator owns the meter. The DNOs have given Meter Operator staff training on removing and replacing cutout fuses and seals, and may do so on behalf of the DNO. 


Regards,


Alan.