AFDDs are a massive fraud

[marconi]

I have not read or looked at what you attached - sorry I am pre-occupied with two projects at the moment.

I have not thought (yet) too much on AFDs and take your point about the UK system with magnetic/thermal mcbs, RCDs and care about wiring and earth fault impedances being successful in some/most situations of detecting parallel arc faults ie between live conductors or between line and earth and neutral and earth. I too am dubious about their efficacy in the UK setting and great potential for nuisance tripping undermining their merit.

I asked earlier 'why now' had AFDs been introduced into our wiring regulations by the IET. I don't know the answer (yet) but assumed it was to deal perhaps with serial arc faults as might be found at loose wiring connections which mcbs and RCDS usually will not detect. But then too there is the great potential for nuisance tripping of AFDs installed to detect serial arc faults as switches are opened and closed. I doubt the current state of AFD technology can distinguish reliably between true serial arc faults of wiring and normal switch operation.

I don't know enough to state a professional opinion on AFDs but do think Cookie is being genuine about how poorly AFDs perform in practice in the USA.

PS: It adds to the interest of a poster if we at least know where they hail from though no need to give one's actual address. Recently, I quite liked to know the EF was helping a chap in Addis Ababa.

 

[Cookie]

I asked earlier 'why now' had AFDs been introduced into our wiring regulations by the IET.

The plan is to make AFDDs global. The IEC now recommends them thanks to UL being so heavily involved with the IEC and its committees.

I'll find the link, but they also have members from Eaton on those committees. The bias is to obvious.

I don't know the answer (yet) but assumed it was to deal perhaps with serial arc faults as might be found at loose wiring connections which mcbs and RCDS usually will not detect. But then too there is the great potential for nuisance tripping of AFDs installed to detect serial arc faults as switches are opened and closed. I doubt the current state of AFD technology can distinguish reliably between true serial arc faults of wiring and normal switch operation.

Truth is they can't. This is the norm in US forums:

Article 700 Emergency power components

Starting with a 700.2 compliant Emergency Power System, also known as Life Safety, with a generator meeting NFPA 110 and an ATS listed under UL1008. Customer wants to add a portable generator docking station with quick-connect plugs (aka CamLok plugs) and a manual transfer switch, also UL1008...

forums.mikeholt.com

But even if they could reliably detect serial arcs (and even glowing connections) mandating them is wrong because code should not dictate technology. Point of use thermal detection can detect serial arcing at fittings and with a much high degree of accuracy in theory. Think Thermarestor as an example. If flex was screened that would detect a series break by tripping the RCD.

I don't know enough to state a professional opinion on AFDs but do think Cookie is being genuine about how poorly AFDs perform in practice in the USA.

The US is rather eye opening, it will tell you everything you need to know.

 

[static zap]

...Tripping has also been reported for MV faults outside the structure, faults on other circuits and tripping without anything connected the breaker. Even RFI has been known to trip them:.....

Feeling your pain ,
formerly whole houses on dual 30mA RCDs
with similar waking up "in the dark" experiences.
In the name of safety !

 

[JK-Electrical]

I have read the thread and it has connotations with other fables I read such as "man did not set foot on the moon"or "the illuminati are hell bent on controlling this planet," (one world government)

If one world government is a "fable", then why are all these prominent people talking about the creation of a one world government?

Conspiracy theories abound and conspiracy theorists are ever ready to find motive where none may exist

Likewise, coincidence theories abound, and coincidence theorists are ever ready to deny motive where motive may have existed.

 

[Cookie]

Feeling your pain ,
formerly whole houses on dual 30mA RCDs
with similar waking up "in the dark" experiences.
In the name of safety !

Thanks for understanding. But RCDs have actually been shown to protect people and property.And be happy your usually have no electronics. 100% of US RCDs are of the voltage dependent type.

 

[Deleted member 26818]

Perhaps I’m cynical?
The 18th edition now has a number of requirements or advisories which appear to have nothing to do with safety, but are more to do with increasing profits for manufacturers.

We can now no longer use anything other than a Type tested DB in domestic installations.
That means we cannot use items of equipment from different manufacturers, even if all of the items of equipment have a greater breaking capacity than the measured PFC.

We now have to follow Manufacturers’ Instructions in respect of DBs.
This means we have to install items of equipment rated at what the manufacturer’s require, rather than rated according to the expected load.

BS7671 now no longer lists RCD sockets or RCD FCUs as being acceptable for additional protection.
This means many installations will require a new DB be installed just to provide RCD protection for an extra socket.

BS7671 now requires circuits supplying luminaires be provided with RCD protection.
So again a new DB when installing an extra light.

We are now advised to install SPDs to prevent damage from lightning strikes.
This is despite the fact that damage to consumer installations from lightning strikes is very rare and occurs much less often than damage caused by loss of supply neutral.
Is it a case of safeguarding the DNOs against compensation claims, rather than protecting customer’s equipment against lightning damage?

As for AFDDs, my understanding, is that they are very unreliable and won’t work with RFCs.

 

[Cookie]

It will only get worse unless people put a stop to it. They count on your silence and compliance as consent. US electricians are starting to see the light. Another case in point:

Equipment Grounding question

All, Please see picture attached. Is this the correct size grounding conductor required for equipment grounding? 2 of the power panels have 100A main breaker and the other 2 have 150A main breaker. The transformers are 25KVA. The Fiber panel is a Corning ICH-12P, Nema 3S, I believe. A #4 seems...

forums.mikeholt.com

The GFCI requirements are coming from people getting killed on none compliant installations. So how will mandating more GFCIs solve the issue of people refusing to follow the code in the first place? And speaking of that handy work is getting worse because home owners don't understand why an electrician costs 5x as much with call backs vs a handy men that won't cause $500 worth of groceries to go bad when the fridge AFCI trips.

https://www.hbag.org/uploads/5/7/9/1/57910935/technical_service_pointer.pdf

 

[marconi]

Cookie - please indulge me - where are you in the USA, at least by state if not city/town?

You have sparked off a good discussion and getting some fine folk contributing and following.

 

[gutterball]

Have a look at the John Ward videos on youtube when he tested one.

 

[Cookie]

Have a look at the John Ward videos on youtube when he tested one.

Yup, saw them. And a perfect example of why they don't work. Most appliances draw less then 5 amps and most circuits are loaded below that as well. Joule heating can take place under 1 amp. So right here we do not have any fire protection, and above 5 amps its hit or miss... because it may just be an appliance doing its normal thing.

Which brings me to the arc detection logic itself. You need the computing power of at least an Iphone to get reliable discrimination. And even then the AFDD must be programmed to take into account thousands of benign waveforms "learning" what is ok and what isn't. The whole concept even with the right intentions is impractical. Maybe as computing power increases and cost decreases but till then- no.

 

[Pete999]

Yup, saw them. And a perfect example of why they don't work. Most appliances draw less then 5 amps and most circuits are loaded below that as well. Joule heating can take place under 1 amp. So right here we do not have any fire protection, and above 5 amps its hit or miss... because it may just be an appliance doing its normal thing.

Which brings me to the arc detection logic itself. You need the computing power of at least an Iphone to get reliable discrimination. And even then the AFDD must be programmed to take into account thousands of benign waveforms "learning" what is ok and what isn't. The whole concept even with the right intentions is impractical. Maybe as computing power increases and cost decreases but till then- no.

If anyone doesn't know what Joule heating is here is a description

joule heating - Bing

Intelligent search from Bing makes it easier to quickly find what you’re looking for and rewards you.

www.bing.com

Although quite what it has to do with AFDDs is questionable to say the least

 

[static zap]

If anyone doesn't know what Joule heating is here is a description

joule heating - Bing

Intelligent search from Bing makes it easier to quickly find what you’re looking for and rewards you.

www.bing.com

(That one put me to sleep.)
100% Efficient conversion of electrical energy to heat,
in a region of high relative Resistance ,
I squared R Losses . (or am I wrong)

 

[Cookie]

(That one put me to sleep.)
100% Efficient conversion of electrical energy to heat,
in a region of high relative Resistance ,
I squared R Losses . (or am I wrong)

Here is an easier way to understand it:

 

[telectrix]

now you know why we call them fire nuts.

 

[Devonchris]

Very interesting thread. And no doubt there are hundreds of firefighters throughout the country breathing a sigh of relief now that they know these things don't work.

They were all thinking they would have to start doing a proper fire investigation instead of the old standby, cause of fire, "electrical".

 

[Cookie]

Very interesting thread. And no doubt there are hundreds of firefighters throughout the country breathing a sigh of relief now that they know these things don't work.

They were all thinking they would have to start doing a proper fire investigation instead of the old standby, cause of fire, "electrical".

In the US most fires are written off as "electrical". Unless arson is suspected the fire is not thoroughly investigated. And even then its hard to find a cause when all you have is a pile ashes. So fire statsitcs from the states are very skewed.

Interesting fact: fire sprinklers are actually mandated in US homes but its amended out at the local level 99.99% of the time.

 

[Devonchris]

The Brits have long complained that many Americans don't get irony (for instance, we published a telling story from a British expat last week, and then there was the time the editor of Business Insider UK griped on Twitter about his literal American editors).
Well, there's a reason we don't get irony, and it's not because we're daft.

the British, despite being more low-context than many cultures, are far more high-context than the Americans. Thus they will often say things with implicit meanings that are contrary to their literal meanings — aka irony — that go right over American heads.

Here's The Real Reason Americans Don't Get Irony

There's a very good historical reason.

www.businessinsider.com

Nothing personal, it's just me. I'm retarded, and am only here for the humour

 

[Devonchris]

Sorry, that should read, RETIRED.

 

[telectrix]

Sorry, that should read, RETIRED.

you were right the first time. .

 

[ipf]

you were right the first time. .

'Just kidding', tel?