Derailed another thread with AFDDs, so I am starting this one. I will simply say that UK RCDs and MCBs provide arc fault protection as is. UL not only knows that, but extensively researched UK power systems in an effort to emulate the very same concept 40 years. One the simply fact (growing concern) that the US National Electrical Code does not prohibit a maximum earth fault loop impedance.
Here is the theory that started it all in the US:
First few minutes of this video explain it. Remember, the US has nothing on loop impedance and some US circuit breakers did not even have a magnetic trip function 40 years ago where as breakers in Europe did.
The the thing is, these uncleared short circuits as a result of lacking earth fault loop impedance are being incorrectly called "arcs"
First few minutes of this video explain it. Remember, the US has nothing on loop impedance and some US circuit breakers did not even have a magnetic trip function 40 years ago where as breakers in Europe did.
The the thing is, these uncleared short circuits as a result of lacking earth fault loop impedance are being incorrectly called "arcs"
T
The Ghost
I have looked at your contributions regards RCD as AFDD and on the surface it seems a compelling argument that it is true that RCD are AFD devices. The technicalities presented certainly superficially are a revelation and indicate a massive fraud if it is true. I note the report is from the 1980s' and wonder if further work or research has been done on this to your knowledge. A cursory search reveals only info on AFDD info.
I don't have time now to get caught up in this debate, but one quick thought;
We have to be a careful comparing US 120V circuits with European 230V. I appreciate that many US buildings have a few 240V circuits too, but numerically the 120V circuit prevails. Some important parameters vary as the square of the voltage or current, so there can be a factor of four differentiating the behaviour of US and UK general purpose circuits. Series arcs also have noticeably different characteristics and form in different situations at 230V vs. 120V. When looking statistically at the causes of actual fires, as well as detail differences in electrical technique, such as the kind of conduit used (or not), one has to allow for differences in building construction, climate and other external factors that affect how a particular electrical event relates to a fire outcome.
It is a complex subject and for the fireside observer, personal opinions about 'fraud' and 'rip-offs' are likely to heavily bias the view of what little technical information is available from controlled studies.
We have to be a careful comparing US 120V circuits with European 230V. I appreciate that many US buildings have a few 240V circuits too, but numerically the 120V circuit prevails. Some important parameters vary as the square of the voltage or current, so there can be a factor of four differentiating the behaviour of US and UK general purpose circuits. Series arcs also have noticeably different characteristics and form in different situations at 230V vs. 120V. When looking statistically at the causes of actual fires, as well as detail differences in electrical technique, such as the kind of conduit used (or not), one has to allow for differences in building construction, climate and other external factors that affect how a particular electrical event relates to a fire outcome.
It is a complex subject and for the fireside observer, personal opinions about 'fraud' and 'rip-offs' are likely to heavily bias the view of what little technical information is available from controlled studies.
Eventually US manufacturers lowered or added magnetic trip to around 10x the handle rating.
The first AFCI was proposed to simply be a low magnetic trip breaker.
Research was done and it was theorized that the lowest perspective short circuit current at the panel (consumer unit) plus the highest anticipated circuit impedance would result in a minimum short circuit current of 75amps at the furthest point in the circuit.
However a 75 amp magnetic pickup would result on tripping on inrush with vaccuum cleaners, window ACs and even incandescent light bulbs burning out.
Thus came the idea of an electronic AFCI. One that could discriminate between the current surge of a vacuum cleaner starting and that of a short circuit. Although come reality electricians were and still do get call backs on vaccum cleaners and tools tripping AFCIs.
Even Joseph C Engel, one of the main developers of the electronic AFCIs now has his doubts:
My reply from my other thread:
An AFDD is money secured for the manufacturer. Come time AFDDs will probably have self test logic, meaning they will lock out every X years and require replacement. Already being done with US GFCIs.
AFCIs got into the NEC because manufacturers (like Eaton) bribed the code making panels and UL. They want to and are grdually doing the same with the IEC through committees.
Manufacturers know electrical equipment is near perfected and cheap, I mean what else is capable of lasting 60+ years? But if you require products through mandates, especially products that will require replacement the financial reward is in orders of magnitude greater then before. Investing millions will give you billions, and investing billions will give you trillions. With millions and billions its not hard to cook up a lie one great enough that most everyone will believe.
The first AFCI was proposed to simply be a low magnetic trip breaker.
Research was done and it was theorized that the lowest perspective short circuit current at the panel (consumer unit) plus the highest anticipated circuit impedance would result in a minimum short circuit current of 75amps at the furthest point in the circuit.
However a 75 amp magnetic pickup would result on tripping on inrush with vaccuum cleaners, window ACs and even incandescent light bulbs burning out.
Thus came the idea of an electronic AFCI. One that could discriminate between the current surge of a vacuum cleaner starting and that of a short circuit. Although come reality electricians were and still do get call backs on vaccum cleaners and tools tripping AFCIs.
Even Joseph C Engel, one of the main developers of the electronic AFCIs now has his doubts:
My reply from my other thread:
An AFDD is money secured for the manufacturer. Come time AFDDs will probably have self test logic, meaning they will lock out every X years and require replacement. Already being done with US GFCIs.
AFCIs got into the NEC because manufacturers (like Eaton) bribed the code making panels and UL. They want to and are grdually doing the same with the IEC through committees.
Manufacturers know electrical equipment is near perfected and cheap, I mean what else is capable of lasting 60+ years? But if you require products through mandates, especially products that will require replacement the financial reward is in orders of magnitude greater then before. Investing millions will give you billions, and investing billions will give you trillions. With millions and billions its not hard to cook up a lie one great enough that most everyone will believe.
Of course. And do you seriously believe the IEC/BS7671 has not addressed the risk of of having a higher voltage to ground long ago?
Have a look at this:
The poster admits that it blew the 16 amp fuse the circuit was run for but not the 32 amp fuse. Further if that circuit had an RCD, the RCD would also have tripped since there is an earthing conductor sandwiched between the live and neutral.
Loop impedance, disconnect times and RCDs are not just about protecting people, but also mitigating fires as well.
The US on the other hand has never had disconnect times or loop impedance requirements...
The studies in of themselves show the history, one which says the UK system in its current state does the exact same thing as an AFCI.
Remember that this all started with people trying to emulate the British/EU system and thats stated on black and white.
This site:
Rick Franklin, Forensic Engineer | Curriculum Vitae
forensic engineers, curriculum vitae, Rick Franklin, Frederick Franklin, Cincinnati, Midwest, PACE Inc., building fires, vehicle defects, vehicle fires, equipment failures, accident reconstructions
AFCI Seminar for Fire Investigators
AFCI seminar for fire investigators developed by forensic engineer Rick Franklin, P.E., Cincinnati, Ohio.
Reason I keep linking to him is that manufacturers were not only inspired by his theory, but UL also repeatedly sites his findings using it as a bases for picking up where he left off.
What you need to know about Arc Fault Detection Devices
New to the 18th Edition Wiring Regulations is the recommendation of AFDD's. We have put together a complete guide to help you understand what an AFDD is.
www.electriciancourses4u.co.uk
Yes, and if twin and earth is damaged a parallel arc is between two points: live to earth or live to neutral. Live to earth is covered with the RCD and breaker coil, live to neutral via the breaker's magnetic trip coil.
So any parallel protection an AFCI offers is redundant at best.
Does anyone in the EF know what the 'tipping point' was to introduce the recent BS7671 requirements for AFDDs? Or did the technology and products become available and were then (necessarily) introduced into the B7671 requirements? Or has the requirement come from a fire brigade investigation and report as did the metal CUs.
Some sensing an Arc before it can produce any sort of heat makes it redundant does it? mind if I ask you a question? firstly you come on the Forum with a legitimate question about possible brown out in a Hospital complex, which turns into a thread comparing US and UK OCPDs RCDS and concluding your argument by saying AFDDs are redundant, Question what is your game?
Well, I don't think you would be to happy if I told you arcing is the end stage of joule heating...
Not so much comparing as showing proof of my claims. Manufacter backed UL and others were literally researching UK/EU power systems with the intent of emulating the system here in the US leading to electronic AFCIs. Now these same manufacturers turn to the IET/IEC claiming they have a new product solving a problem that no technology has ever tackled before.
I derailed in the hospital thread- but since the subject was touched I might as well let knowledge on this hot button issue spill out.
Without going back over the entire thread, What or Who is UL?
USA Underwriters Lab regulatory body
(insurance linked)
Underwriters Laboratories
UL Solutions
UL Solutions is a global independent safety science company with more than a century of expertise innovating safety solutions.
A once none profit that is now a for profit.
Regarding your statement about joules and heating, the AFDD detects an Arc fault before it reverts to combustion, doesn't it?
That what they claim.
Joule heating (aka high resistance connection) are responsible for most electrical fires and in of themselves do not produce arcing. When they do, it is often near the end stage (terminal is already glowing and falling apart), not the start.
That would be when the AFDD trips the circuit Off then before that happens.
Perhaps now, but give it time. They will not only become mandatory, but eventually require self test logic (planed obsolescence) with a slew of devices to also follow. The American NEC is already a product catalog and getting worse each cycle. 2020 is going to be raunchy.
What time is where you are? Sun's over the yardarm here, I'd recommend a stiff drink, or whatever trips your device.
what about an arc L-L or N-N? e.g. on a fractured cable.
LOL- asking me for a locationWe can still be friends though
Well you live somewher, presumably?
Not being that nosey, just getting a feel for the bad habits you may have picked up.
(touch testing for 120V to earth !)
Helps us chose relevant advice.
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)
Conspiracy theories abound and conspiracy theorists are ever ready to find motive where none may exist
The Iet (bless em) are not anything other than a bunch of sometimes impressionable folk, who happen to have lived their lives(like us) thinking electrons,they are not best placed to accept nonsense too often
They have been and will be susceptible to dodgy influence on occasion but not where technical issues are concerned
The concern in this thread smells like little more than conspiracy theory and big business is on the prowl mentality
Conspiracy theories abound and conspiracy theorists are ever ready to find motive where none may exist
The Iet (bless em) are not anything other than a bunch of sometimes impressionable folk, who happen to have lived their lives(like us) thinking electrons,they are not best placed to accept nonsense too often
They have been and will be susceptible to dodgy influence on occasion but not where technical issues are concerned
The concern in this thread smells like little more than conspiracy theory and big business is on the prowl mentality
Conspiracy theories are just that, theories. People jumping to fantastic conclusions based on incomplete information or bodged journalism.
On the other hand we not only have ample evidence saying so but also science calling AFDDs out as marketing hubris.
Nowhere will you find official documents saying XZY never happened or ABC is just a hologram however here in black and white the creators and researchers of AFCIs freely admit their efforts of trying to mimic European circuit breakers. It can not be any clearer.
Just because a few trolls out in the internet abyss have ruined any view of descent by being vicious unhinged bullies does not make every single person who calls out bad ideas as crazy or a conspiracy theorist.
You do realize that most US electricians hate AFCIs with a passion for all the call backs. Litterally every other day there is a thread on US electrical forums for AFCIs nusinace tripping without cause. The circuit will hold on a GFCI breaker, the romex is meggered, the connections checked and rechecked yet they still trip at random times without reason. 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:
Eaton has since claimed to have resolved the above but nuisance tripping is still going on to this day even with new breakers of all manufacturers.
And by the power of logic if they can trip on LED lighting and functioning appliances who says they can or will trip on supposed dangerous arcing?
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