Arc fault detection mcb, Breakers

[Duane B]

AFDD "Ark Fault Detection" mcb breaker.

Do we really need this . the ones I've seen are double the size of an mcb. rcbo. so would take up 2 ways for one mcb, breaker

Afdd system, Arc fault detection devices are extremely sensitive and designed to sense and respond only to potentially dangerous arcs. They use a special algorithm to distinguish between dangerous and working arcs – i.e. the harmless sparks that you see when you flick a switch or pull a plug.
This is important as over-sensitive AFDDs could be prone to nuisance tripping – e.g. interrupting a circuit when it senses the slightest harmless arc 

Suppose 18th edition is gearing up for metal clad boards with a full rack of these in it. more outlay for sparks and a new book to go with it

 

[Tony S]

Was the original ark fault Noah crashing in to Mount Sinai?

I’ve a lot of information on AFCI’s going right back to the original inception. Let me put it together in some sort of chronological order. It will take me an hour or two which is a bloody site quicker than the IET steering committee cobbling the 18th together.

 

[Sharpend]

Was the original ark fault Noah crashing in to Mount Sinai?

Didnt he land on the mountains of Turkey? Sure the remains of the Ark were found there? 

 

[Blue Duck]

Did some reading on this a while back when it last reared its ugly head.

Seems like madness to me, I thought our electrical systems were some of the safest in the world, "IF IT AINT BROKE DONT FIX IT" springs to mind.

The basics of what I have taken in are that, they don't work & you can't feasibly test them which would make fault finding (on your time) a ballache.

Wiki https://en.wikipedia.org/wiki/Arc-fault_circuit_interrupter for simpletons like me....

Guess who's behind all this:  http://blog.schneider-electric.com/power-management-metering-monitoring-power-quality/2013/07/03/do-you-know-an-arc-fault-detection-device-afdd-can-prevent-from-an-electrical-fire/  :shakehead

The schneider guide to fault finding I posted earlier headbang  http://download.schneider-electric.com/files?p_Reference=CA908056E&p_EnDocType=User guide&p_File_Id=2167826188&p_File_Name=CA908056E+(web).pdf basically reads: if it trips you're courgetteed.

How to fix one: http://www.familyhandyman.com/electrical/breaker-box/fix-a-sensitive-arc-fault-circuit-breaker/view-all :slap

I'm sure someone will post some more accurate technical info, I did this to get the ball rolling and to keep sharpend away from Mt Sinai.

One last thing.... Can WE actually stop them implementing this?

 

[Tony S]

NFPA-NEC 2002.

AFDD’s (AFCI) were introduced in to america to combat fires started by series and parallel arc faults. They do this by detecting arc signatures and opening the CB.

Originally they were only mandated for 120V Ph→N circuits in certain areas of a dwelling. Now they are mandated for almost all areas. For some reason 240V circuits Ph→Ph are except. (I’ve an idea why but as yet no proof).

Once they were introduced the trouble started, circuits tripping for no apparent reason. With no test equipment available, fault finding consisted of “swap out” IE pulling a circuit to bits, changing accessories, checking connections, etc. AKA running around like a headless chicken, while at the same time trying to convince the householder you know what you’re doing.

The concept of the AFCI originated with Joe C. Engel IEEE.

The manufacturers and the underwriting laboratories drew up the AFCI UL testing methods between themselves (UL1699). These were put to the NEC-CMP and accepted.

AFCI’s are only mandated for 120V Ph→N circuits, 240V Ph→Ph are not covered.

First introduced in to the NFPA-NEC 2002 as mandated for bedroom receptacles.

NFPA-NEC 2008 combination GFCI/AFCI’s were introduced and extended the mandated areas to cover to all living areas.

Following masses of complaints the combination GFCI/AFCI’s fell out of favour “not fit for purpose”.

AFCI’s are still mandated for all living areas and from what I’ve seen of the NEC 2017 they are still there.

The manufacturers and the underwriting laboratories drew up the AFCI UL testing methods between themselves (UL1699). Does anything strike you as odd with this arrangement?

From a letter from Joe Engel

The author created the described condition in his shop, and tested all commercial Combination AFCIs; none tripped and turned off the circuit. Further, the author used cotton to verify if the arc was a fire hazard. The author could not ignite the cotton.

The UL test methods are basically flawed. Little gems like using 2000V to establish the arc before the 120V AFCI is switched in to the test circuit.

After denouncing his own creation as totally unreliable Joe Engel was force to emigrate.

Now just to inspire your confidence in the IET making the right decision about AFDD’s BS-EN62606 is virtually a photocopy of UL1699 (only the voltages have been changed to protect the guilty)

 

[Sharpend]

Well clearly these are far more less believable than Noah and his ark 

 

[Tony S]

Just wait until you have to fit them and then explain why the power keeps going off since you fitted that expensive trip thingy. You’ll never hear the last of “it was alright before you messed with it!”

 

[Tony S]

One last thing.... Can WE actually stop them implementing this?

They’re already in Am3 cleverly disguised under ADS

 

[Duane B]

Why why why. it's just too much. we're already over the top now on everything we do. what happens when a fridge becomes a bit worn after you have upgraded a customers house. trip trip trip trip. does not seem good to be honest.  can we stop it. seems as though testing will become a pain in the ass. suppose you need to bypass them or  hold yep gotta a buy an 18th edition test instrument to test. 

I have heard that some have some kind of smart monitoring chip in them. a smart breaker. "test Procedures" originally designed for American market I believe where they have a multitude of corded appliances plugged in. hence protection if the cord. not to mention in the UK we would need a c/u 6x the size to fit em all in. stealth ADS. Hmmmmmm .  just what next

 

[Tony S]

They’re already in Am3 cleverly disguised under ADS

BS7671 Am3

532.1 (ii) note 3

 

[Duane B]

http://www.codecheck.com/cc/ccimages/PDFs/AFCIsComeOfAge.pdf

Read the what can go wrong section.on above link

Www.eaton.com

Eaton do a great pdf explanation of it

 

[Rob.]

Having spent the last year working quite closely with UL and their standards. (Honestly some rules don't even follow physics in how they come to decisions. Just look up how they decide to come about rating a systems KA rating) It really doesn't surprise me that they are behind something like this. 

 

[Sisyphus]

Yes Arc Fault technology violates https://en.wikipedia.org/wiki/Paschen's_law]Paschens law[/url]  at the lower voltages we have in the USA Rob

Makes perfect sense for all the poco applications (SCADA) it's used for.

And yes, UL took it upon themselves to create a standard, as opposed to testing towards any given manufacturers claim to one, which was unprecedented 

The 'UL simulator'>

[/img]

The  actual device>>>

[/img]

The 'zip cord' ,cut with a razor,wrapped in flammable tape, and subjected to kilovolts via said device>>>

[/img]

All of which can be found in Dr Joe Engel's Arc fault paper  , as Tony stated.

~S~

 

[Rob_the_rich]

BS7671 Am3

532.1 (ii) note 3

To be a bit pedantic, it isn't under ADS, it is only relevant to 422.3.9 (under "locations with risk of fire due to the nature of processed or stored materials") and it is an optional addition to the measures 532.1 (I) or (ii). I can understand why arcs might not be a good idea in these circumstances, and looking at note 2 there seems to be a suite of BS ENs for explosion risk locations, but it does seem OTT to bring these devices into a domestic installation.

 

[Slowhand]

I wonder if in 30 years some less than honest sparks will look at 17th edition boards and say..

" RCD's, haven't seen one of those for years."

" They had to stop using them because they were dangerous, they catch fire for no reason so you need a new consumer unit and complete rewire."

" You need AFDD's or you're not insured....."

Etc etc etc

Just like they do now about 3036 boards.

 

[Tony S]

There are manufacturer specific test sets for AFDD’s, non of which give a reading you could write on a test certificate. Unlike a RCD where you can test and give definite figures for sensitivity and operating time you will be stuck with a pass/fail light. Pass or fail on what? only the manufacturers know that.

1. The Americans have no test procedures for new installations or an EICR system.
   
2. Wiring accessories tend to use wrap around terminals unlike our tunnel terminals making them prone to loose connections.
   
3. Duplex receptacles tend to be 180° opposed so the power cord from the top receptacle has to bend through 180° to reach floor level whereas with a BS1363 dual outlet the power cord naturally exits downward.
   
4. Appliances often use figure of 8 power cords with no over sheath leaving the insulation prone to damage.
   

 

[Sidewinder]

A question has just been sent to a JPEL/64 panel member for further information & advice/support...

 

[Tony S]

Will there be a definitive yes or no?

 

[Sidewinder]

I doubt that there will be a definitive yes or no, because the question was not phrased to engender such an answer!

 

[Tony S]

If there was a straight forward answer it will be in 897-1 (ii) subparagraph B with reference to 697-3