My understanding (which may well be incomplete or wrong) is that the standard's tests for AFDDs work on the assumption that once there is a break in a cable which causes intermittent arcing, the arcing chars some of the insulation over time, and the carbon makes future arcing easier. So the tests are with carbon rods. A lot of the youtube tests try to create arcs with small copper to copper gaps, which tend not to last more than a second or two, and may be seen by the AFDD as a motor-type spark and not trigger a disconnect.

So when a youtuber shows an AFDD failing to disconnect, it may be that the AFDD is actually working correctly. Or it may be being completely useless. Or the standard isn't up to scratch. We can't tell from the video.

mapj1 said:

the acceptance tests as written in the standard are not especially realistic of faults as they occur in the real world.

Maybe the people who write the UK standard need to revisit the standard?

It is not a UK specific standard, it is a European one, and it in turn it is heavily based on the US one. But yes, I would strongly support a bit more transparency about what AFFDs must detect by design to pass type approval, then what else they may detect as a bonus,  and what they  must not trip on,  to avoid false alarms, as well as how well or badly they reject arc like interference coming from the supply side.

The technology is not especially complex by electronic digital signal processing standards - essentially sampling, then Fourier transforms and some spectral pattern recognition, but it is very, very  different to the one condition-one trip operation we associate with existing protective devices.

And I think it really should be testable in the field.

Mike.

mapj1 said:

It is not a UK specific standard, it is a European one, and it in turn it is heavily based on the US one

My understanding is that a US AFDD is quite different to a UK AFDD

I also think that test instrument manufacturers like CA (Chauvin Arnoux) , TIS(Test Instruments Solutions), Megger should be involved with writing the standard that way they can make test kit for the AFDD device for the UK market. 

https://blog.se.com/energy-management-energy-efficiency/energy-regulations/2013/07/09/iec-62606-a-first-step-towards-international-standards-for-arc-fault-protection/

https://www.export.legrand.com/en/white-paper-detection-electrical-arcs

And the American tests are described here (as with Europe the standard itself is expensive, but other folk have discussed it enough that the main tests are well known - and unlike the Euronorms, there is free digital viewing, although copying is forbidden.

https://code-authorities.ul.com/wp-content/uploads/2014/05/Dini2.pdf

https://www.shopulstandards.com/ProductDetail.aspx?productId=UL1699_3_S_20170503

Mike,

Well, given what we have seen and experienced thus far, i would say that these things are next to useless, immature to market, and try to solve a problem which really isn't out there in the real world to any great extent. Surge protection in domestic consumer units was a hard sell but it was swallowed even though it stuck in the gullet, but these things are a very expensive step too far. The technology is not provable and I am surprised that the IET got suckered into mandating these things at all. I would urge that extreme caution be applied to installing these things. There is no come-back on the manufacturer because the things cannot be proved to work in the field either way, so guess who is left holding the baby when things go pear-shaped.

Me? I'm not going near them.

Well put!

It is a bit of a conundrum. Refuse to fit and the worst may be a C3 on any future EICR. Fit one and it doesn't work, and a life or property is lost and it's a trip to the High court,hopefully with deeper pockets than those of the manufacturer, who will swear blind that the thing worked 'But you didn't set it up properly, or you didn't install the latest firmware update' There's no means of testing for satisfactory operation either way, so why put yourself at risk in the first place?

Nope, a C3 will do me..

My understanding is that AFDDs have been used in Germany for several years now.  I wonder if they are the same type as that used in the UK?  It would be interesting to know how the Germany Electrcian/Technician see this product?  Are the UK issues we see due to the AFDD being used on a ring final circuit rather than a radial?  Is th cable used a factor, T&E with exposed Earth/CPC?

Maybe some imput from AFDD manufacturers could help to further the debate. 

If you want the German electricians' discussions on this topic, search for Fehlerlichtbogen-Schutzeinrichtung, (AccidentalArcSafetyDevice)

or in or in more informal debate/documents Brandschutzschalter (FireSafetySwitch). Naturally you will need to speak German, or make much use of google translate to make sense of the search results.

This is a typical rant....

https://www.handwerksblatt.de/themen-specials/hitzige-debatte-um-brandschutzschalter/afdd-norm-brandschutzschalter-notwendig-oder-ueberfluessig

regds/mfg

Mike

It is interesting to read that our German colleagues are unhappy about AFDDs as well.  The cost and the way it was forced onto them by industry rather than sound technical engineering. It would good if anyone can reach out to any German Electrcians/Technicians that speak/write English to join the debate.  Are German AFDDs suffering from the same hit and miss scenario as the UK AFDDs?  Do the Germans have a way to test the AFDD in the feild for trip/no trip verification?  Are some of the AFDD used in Germany over sensitive?

It is interesting to read that our German colleagues are unhappy about AFDDs as well.  The cost and the way it was forced onto them by industry rather than sound technical engineering. It would good if anyone can reach out to any German Electrcians/Technicians that speak/write English to join the debate.  Are German AFDDs suffering from the same hit and miss scenario as the UK AFDDs?  Do the Germans have a way to test the AFDD in the feild for trip/no trip verification?  Are some of the AFDD used in Germany over sensitive?

You may find the more recent German changes informative also.

https://www.handwerksblatt.de/themen-specials/hitzige-debatte-um-brandschutzschalter/neue-regelung-fur-brandschutzschalter

To save you some translation effort. I attach the google translation below.

Also on other fora the general fermentation is that it is a victory for common sense, as now German electricians are free to do an RA to see if they need AFDD in a particular situation or not.  Reading between the lines, I think that many will now be deciding 'not' unless it is wiring for a  fuel dump or an art gallery..

regards Mike.

"

Well, judging by that, it seems that good old engineering common sense has prevailed over the marketing hype for once, and about time too.

Since JPLE64 or whatever they call themselves, seem to have cross border involvement, I wonder why back in Jan 2020, if they were aware of this debacle and subsequent DIN reform at the time, they didn't take it into consideration before mandating AFDDs into BS7671?

Maybe Grenfell, to say "We are doing something?"

Even though it seems to be an appliance that caused the initial fire. Anyone who takes an appliance apart knows they are made to a (low) price point. Their moulded plugs are rubbish, the connections inside are tiny and loose. Yet they get away with it.

Same with the plastic consumer units that were catching fire, but, we know,they couldnt catch fire, as the BS stated it should be made of self extinguishing or non-flammable plastic.But some did not meet the Standard, some Makers were making flammable plastic CUs.

But the Electricians got the blame for loose connections (yes, there were some), and the CU makers didnt get taken to Court for supplying Goods that didnt meet the British Standard they were supposedly tested and certified for. And of course, the Makers then got more income, as metal CUs were called for in high risk places, so , what should have been a perfectly good plastic CU was changed due to the Manufacturers bypassing the Rules, and then they made more money because of that. Cynical, me?

Do JPEL64 publish the minutes to their meetings or could we request the minutes to the meeting where AFDD were discussed and then mandated into BS7671.  If JPEL64, BSI and IET  were aware of what was going on in Germany they could have used the word recommend rather than the world shall.  After all the BS7671 has a definitions section that state what they mean when using the word shall.

We've been there before in another thread.

engx.theiet.org/.../afdds---when-do-they-work

I would urge you to have a look at who sits on the wiring regs committee to find your answers.

Mr Savoury has published another rather humorous Hager AFDD update -

www.youtube.com/watch

Good points well made. Take a look at Mr Savoury's latest youtube missive on the AFDD subject linked above - he makes the point that Hager have, by making their devices firmware updatable, transferred the risk onto any installer who does not keep a keen eye out for any future firmware updates. Basically, you install a few hundred of these across several sites over several years and you are the one responsible if a fire or fatality results as a consequence of you not keenly monitoring and ensuring that every device you install has been updated, so it looks like a lot of tyre wear and diesel consumption for those foolhardly enough to purchase/specify Hager AFDDs both now and in future.No other manufacturer imposes this at present.

I wonder how often the firmware is updated? 

Would an out of date firmware be a C3 on an EICR? (Does anyone here have a up to date copy of code breaker?)

Does the firmware revision need to be checked on the EICR, manufactures instruction seem to lean this way?

Is there a timeframe that the firmwares need to be doneby, can you jump more than one version?

If you have a 16 or 20 way CU/DB and it take 5mins to update each AFDD who will pay for this time?

Can you break the AFDD with a failed firmware update?  Years ago when I did firmware updates on a routers I would take a spare with me onsite.  Safe to say I bricked a few in my time.  To the same affect will the SPark need to carry a spare A6 B6 C6 A10 B10 C10 A20 B20 C20 D20 Hager AFDDs the list goes on.  I think the R&D team at Hager might need to have a look at this and get some imput from the electrician on the ground in the UK and not other EU countries and engineer a way forward.

Enough bashing.  Now lets help.

Hager may well have an idea with being able to upgrade the AFDD.  Fusebox found out the cost of a recall recently.

Could the CU/DB have a bolt on kit to make it internet aware or connect to the internet?  Lets call it a hub.  This hub could interogate the AFDDs in the CU/DB and then report back to the user and/or the installer.  The hub only connects to a Hager secure portal and nothing else.  As with all things on/in the internet the security side is paramount as a compromised system means it could be managed from elsewhere maybe even shut down.  The installer/user could then click the button for a firmware update.  There is a caveat, no load must be connected to the AFDD during the upgrade. 

The road to hell is paved with good intentions - why make it way more complicated than it need be? And more pertinently, who will pay for the time and wear and tear for the travel to site every time a firmware update is issued?

Just don't buy Hager, just buy a different brand until they drop their crazy irresponsible ideas about making everything have to connect to the internet. There is no need if the product is designed properly from the start - Other brands don't have to have web connectivity.

What one man can do, another can undo, the web can never be totally secure.