State of Wisconsin not adopting the use of arc fault breakers at least for the upcoming 2002 - 2005 period. Any others out there holding off as well. Any thoughts on the subject pros cons.

I like the idea of holding off for a while. For the time being offer AFCI protection as an option. After a few years, a track record will exist. Also, the costs probably will have dropped. I don't know if, during a service upgrade, you can convince a customer to foot the extra $200-300 for something most of the competition probably won't insist on anyway.
New construction though, absolutely.

Why do we need this product for new construction. Are our wiring methods so poor that we must provide additional protection for the fixed wiring of the building. If this requirement was for the protection of portable wiring, it would make much more sense to me. The code requires branch circuit protection and most of the branch circuit AFCIs provide only limited protection for the portable wiring. Are we admitting that most of the electrical fires in new construction start as a result of faults in the fixed wiring???????? If so we need to change the wiring methods. Maybe Chicago's all conduit code isn't so silly after all.
Don(resqcapt19)

Dublin,

What I've heard (from a UL rep) basically supports what Don is saying about limited protection to items past the fixed wiring system. I think the problem is in the sensitivity and testing standards in effect. It's ironic that it will be required (here) only in New Construction and not Remodel Jobs (unless more than 50% is renovated)

(What if that 50% does not include the Bedrooms ?? - hmm, not sure )

Bill

My statement regarding new construction was in regard to conforming to the code. Not necessarily agreeing with it.

There was a recent IAEI article per UL1699,on AFCI's. One section stated the listing was for new branch circuits only.
This surprised me as I am being told to AFCI all bed & living area outlets during a service upgrade here in VT. (Yes I know, the NEC is'nt retroactive..)

In asking UL, the listing is supposively being altered for 'old work'. And they are less effective on older circuitry at best.

It's nice to have rationale follow NEC changes, makes it easier to pedal as an end installer/marketer/justifier than simply saying 'because it's code...'.

I try not to ever just say "because it's code". much more professional to say 'this is a code requirement because...." At least this is how I try to explain to the customer, you'd be surprised how much their confidence level in you increases.Besides it drives me nuts, and my helpers and apprentices never say that particular phrase because they know I'll ask why. And I think that drives them nuts. Aren't our jobs great or what.

Then to be totally honest,

This is a code requirement because the manufacturers want to sell expensive breakers on the premis of safety.

Search the internet for Consumer Product Safety Commission
Preventing Home Fires: Arc Fault Circuit Interrupters (AFCIs)



[This message has been edited by Joe Tedesco (edited 12-07-2001).]

Joe,
So you and the CPSC are saying that our installation and wiring methods for the fixed wiring in new dwelling units are so poor that these fires are occurring in the fixed building wiring?
Don(resqcapt19)

Problems in home wiring, like arcing and sparking, are associated with more than 40,000 home fires each year. These fires claim over 350 lives and injure 1,400 victims annually.

Badly collected stat's........

IAEISept/Oct , pg 86;
Concern;
Most of the wiring fires included in the fire studies used by proponents to support the requirements for AFCI's have occured in older dwellings.

Ul's David Dini's reply ........

The tests for UL 1699 for use with NM cable require NM cable with ground, as the NEC requirement section 210-12 would apply to new construction where branch circuit wiring with an equipment ground would be required.

Additional requirements are being proposed for some types of AFCI's to be tested with NM cable without a ground.

You may want to consider adding AFCI protection for both new and existing homes. Older homes with ordinary circuit breakers especially may benefit from the added protection against the arcing faults that can occur in aging wiring systems.

Which would be a listing violation to do....

Don,
This isn't an insult to our fixed wiring.
We are merely the first line of defense.
When GFI's first came out, they were considered by many to be a pain in the tail. We installed them nonetheless. Countless lives have been saved by our installations. Now you get one on the blow dryer you buy.

I see the AFCIs as the same thing. I sleep under an electric blanket that is 5 yrs. old. We have a table lamp that is more than 15 yrs. old in the bedroom. I'm not going to throw them away.
Rather than have a protective device installed on the fixed wiring for your new or remodelled home, do you propose a mandate that all table lamps and electric blankets be thrown away if they don't meet the new Code? Good Luck!
Does anybody in your area use an extension cord or 2? Most homeowners are going to.
A complete educational system for homeowners? Good Luck!
Anything we can do to save lives is a good thing. If it costs the home owner 2 or 3 hundred dollars extra, so be it. It's a lot cheaper than adding the protection to all their plug-in equipment, because they can't get it and won't do it! Ask one!!
We're just the first line of defense. As a fireman, you're also the last.

[This message has been edited by electure (edited 11-30-2001).]

electure,
You are making my point for me. The AFCI required by the code is a branch circuit protection device and only provides limited protection for the types of faults in your post. If we are going to require AFCIs we should wait for the receptacle type that will provide much better protection for arcing faults that originate on the load side of the receptacle. This rule was pushed by the breaker manufactures to get their product into the code at the expense of the development of a superior product. At this point the code does not permit the use of a receptacle type AFCI even if it was on the market. The problem with lack of protection on the load side of the receptacle protected by an AFCI breaker was ever recognized by one breaker manufacturer who submitted a proposal the would have required both AFCI breakers and receptacles. So, I'm not complete against the requirement for AFCIs, I just think it should be revised to provide the most protection. I just don't believe that the majority of electrical fires in newly constructed dwelling units originate in the fixed wiring system. The vast majority originate on the load side of the receptacle where the required AFCI breakers only provide limited protection. Also how will these devices stand up under the test of time? I seem to recall reading that over 50% of GFCIs more than 7 years old are not functional.
Don(resqcapt19)

Don,

Your point is a good one. I too, would like to see them provide more protection past the fixed wiring system to better justify themselves. I do, however see a value in getting them into the new houses now. Agreed, new wiring installations installed properly are quite unlikely to have problems that might justify the existence or need for AFCIs. But once they are in place they should help to minimize the dangers that may arise as a result of modifications that are made to the wiring system by less than 'Qualified' persons. Sooner of later fixtures and wiring devices will be changed, it's almost a certainty. That is where I think they can earn their keep.

Bill

Bill,
By that time, if they have a track record like GFCIs, they probably won't be functional.
Don(resqcapt19)

So.....if 'qualified' were adressed, AFCI's would not be such an urgency.

A limited degree of protection certainly is a lot better than no protection at all.
I agree that the issue should be taken further, to be sure. In the interim, however, I think we should all welcome something that offers any protection at all.
The only objections anyone seems to have here are the cost, which is minimal when you look at the cost of a new home, and their pride.
Why wait??
Do what we can now, and encourage further development!

resqcapt19 Wrote:

"electure,
You are making my point for me. The AFCI required by the code is a branch circuit protection device and only provides limited protection for the types of faults in your post. If we are going to require AFCIs we should wait for the receptacle type that will provide much better protection for arcing faults that originate on the load side of the receptacle. This rule was pushed by the breaker manufactures to get their product into the code at the expense of the development of a superior product. At this point the code does not permit the use of a receptacle type AFCI even if it was on the market. The problem with lack of protection on the load side of the receptacle protected by an AFCI breaker was ever recognized by one breaker manufacturer who submitted a proposal that would have required both AFCI breakers and receptacles. So, I'm not complete against the requirement for AFCIs, I just think it should be revised to provide the most protection. I just don't believe that the majority of electrical fires in newly constructed dwelling units originate in the fixed wiring system. The vast majority originate on the load side of the receptacle where the required AFCI breakers only provide limited protection. Also how will these devices stand up under the test of time? I seem to recall reading that over 50% of GFCIs more than 7 years old are not functional.
Don(resqcapt19)"

Don
Were did you get the 50% failure rate in 7 years figure. I do not have a different one but that does not jibe with my experience. I have three church summer camps in my care as to safety issues. We have installed GFIs on every circuit were we have a possibility of campers using the circuit. The camps are located at or near the ridge lines of mountain ranges and two of the camps suffer lightning strikes every year. We installed the first GFIs in 1984 and completed the work in 1987. All but two are still in service. The two that failed were in a building that had a lightning strike within five feet. That is only two failures out of some sixty GFIs installed fourteen or more years ago.
--
Tom

[This message has been edited by tdhorne (edited 12-01-2001).]

Regardless of their origin, the fact is that the statistics would not exist if someone had not installed the units. If the GFI rules had not been Code , they would still be a seldom used option. No usage=No Database
John Doe still suffers the consequences.

Tom,
I can't find the 7 years reference, but here is a quote from a study by Levition.

"The GFCI Circuit Breaker Field Study, sponsored by The Leviton Institute, reviewed data from 13,380 building inspections and found that 15 percent, on average, of GFCIs were inoperative when tested.he study looked at both GFCI circuit breakers and GFCI receptacles, and found similar failure rates for each. The data suggested that lightning strikes are one likely culprit in many inoperative GFCIs. The study found a much higher incidence of failure in areas where lightning is prevalent. In those regions, as many as 58.2 percent of GFCIs were found to be inoperative."

Note that the high failure rate in is areas where lighting is common. I assume that this is due to spikes damaging the electronics.

Don(resqcapt19)

Don, Tom,

It's my understanding that a signifigant number of failed GFCIs were also reported to be due to exposure to the weather. As a result manufacturer instructions will now include the installation of 'in use' covers where the GFCIs are installed in wet (or damp?) locations.

Bill

Bill,
If that is true, how come the study found similar failure rates for both breakers and receptacles?
Don(resqcapt19)

The 02' ROP's were swampped with requests , mostly from what looked like inspectors,for what leviton now offers in a lockout GFI.

Leviton did'nt surprise me in that most manufacturer's are probably privy to, or somehow involved in the ROP,ROC process.

GFI's track record will probably be paralleled to AFCI's, and i hav'nt seen a tester yet, have you?

The AFCI deal is by far a 'tail waggin' the dog' deal to me , a cheap fix bandaid for future mishaps at best, or those bad installs that are blamed on our trade despite circumstances.
Anyone who's been on scene whatching accelerants ruled out of a smoking cellarhole only to have the guys with the white helmets shrug it off as electrical know stat's lie.
I have nothing against safety,i can pass these costs on, but i'd like to orate without a shred of vocal doubt the justifications to my customers.
Know that safety is BIG biz in this country. And if safety is everyone's biz, then everyone should be looking into the biz of safety.
{anyone what to beat up UL2200???}
I find the AFCI ad's showing a fireman hauling a little girl out of a fire offensive to this end.

Don,

Hmm, .. I have no explanation as to why the failure rates would be the same. I didn't realize it said that. I was repeating something I had heard that sounded plausable. I did hear a UL rep say that the 'in use' covers will be required and that the purpose is to protect the GFCI itself.


Bill


[This message has been edited by Bill Addiss (edited 12-01-2001).]

I hope more states opt out of the AFCI requirement. As i related before the AFCI breakers i used before were junk. Maybe some day, if more reliable breakers are made I'll feel confident enough to recomend them. As for now I will NOT warrent them or use them. When I am forced to install them, I will plan for callbacks and bid accordanly.

VT has updated 210-12 to include 'all living areas', to the point where ONE 40-50A AFCI run subpanel may be more economical than 1/2 dz 20A breakers. There is also some talk of a combo unit AFCI/GFCI, which would allow meeting the $#@% code even easier in this respect.

anyone found this widget yet??



An ammended 215.9 would allow this.
or is the end result the same???

At least it would amount ot one funky device, one callback, one part to eat, with the list growing it becomes a point to entertain;

All Kit circ's
All outside rec's, pools, outbuildings...
All Bath circ's
All Liv circ's
All Bed circ's
Any Hot tub circ's

anyone wish to elude to 2005 or beyond?

[This message has been edited by sparky (edited 12-03-2001).]

I kind of like the ideas of POU [Point Of Use], or POC [Point Of Connection] type AFCI equipment - similar to the GFCIs intregally used with cord caps on things like Blowdryers, etc.

Houses with existing K&T could [maybe??] benifit from AFCI breakers - to protect against arc faults from chipped off insulation and random contacting metallic items, or even the "Wannabe Sparky Rodents"

The concept is a good one. They just need to be perfected, so the nuicance tripping events can be highly limited - otherwise consumers will do as they have with nuicance tripping GFCIs; "Bypass That Darn Thing!!!"

We all have gone through major discussions concerning personal safety equipment in various forums [IAEI, MHE and here at ECN], so we're all aware of the other persons' feelings and ideas of just what to do.

So once again, I'll make my statements of being pro safety items which either reduce or eliminate Electrical Hazards to persons - ranging from Fires to Electrocution.
In order for this to exist, the protecting devices must be as failsafe as possible and as reliable as possible. This means extensive testing, reliability and "Crowbarring" themselves if they fail.

Lastly, these devices should be cost controlled, so it doesn't become an issue between "Can I Afford It" and "I Can't Replace It Because It's Too Expensive"

That's the views from me - Mr. Liberal!!!

Scott SET

With any change, there is always some confusion. I will try to provide some insight into some of the issues that I see in this string. I'm sure I will get a lot of replies, and will try to check back once a day to try to clarify.

First, by means of introduction, I am Eaton | Cutler-Hammer's Product Manager for residential circuit breakers including AFCI. I have been deeply involved in demonstrating, presenting and advocating for the use of AFCI for more than 3 years. I have lived this product, and have heard many of these issues before.

Last week, I was at a meeting that was attended by the President of the National Association of State Fire Marshalls. He said that he was told by an instructor at an early age that all he could ever hope to do was fight a fire...that he could never prevent one. He then went on to say that in all of his years in public fire service that "This was the first product that he has ever seen that has the ability to prevent fires."

NASFM, CPSC and others have endorsed the technology. We have endeavored to get this into the code not because we "want to sell expensive breakers on the premise of safety" as someone in this string has written, but rather because there is a significant problem of electrical fires in the U.S.

40,000 residential electrical fires each year
350 deaths in those fires
1,400 injuries
$700 million in property losses

Even if you do not have a fire in your home, you are paying for this in your insurance premiums. Due to the aging of the installed base of homes (many of which were built after WWII and are now reaching 60 years of age) the problem will get worse before it gets better.

Now to the issues:

Why in new homes? We have to start somewhere, and since you cannot mandate the retrofit into all the existing homes, the logical start is in new construction. This is how buildings are changed, although the process is far too long (18 years for GFCI). Also these new homes will not be new forever. How long do builders hope their new homes will be around? 70-80-90-100+ years? The new homes are larger with more wire in them than 3, 4 or 5 homes that are 70 years old now.

In commercial construction, you install wires in conduit so that when that wire reaches the end of its useful life, you simply pull it out, and pull new wire. What options does a homeowner have to rewire the home? This is an expensive, dirty job that few homeowners and electricians want to get into. So how do you protect those old wires whose insulation is cracked and broken with no barrier to prevent it from arcing?

Over the years, surges, overvoltages, homeowner abuse (have you ever put a nail in a wall to hang a picture without knowing what's behind the drywall?) all create potentially dangerous situations, and contribute to the 40,000 fires each year.

Clearly the terminology of "new construction" needs to be removed from serious dialog regarding AFCI. The purpose of the code is not to protect the home for the first few years of existence, but for the life of the building.

Receptacle AFCI's:

Someone stated that the receptacle type device would provide better protection. This is a false, and dangerous statement. 40% of electrical fires occur behind the walls, in the ceilings and in the floors between the loadcenter and the receptacle. The arcs in this area tend to be the more dangerous parallel arcs that have much higher energy and capacity to create a fire. How does a receptacle hope to prevent an upstream event?

Additionally, there is not a receptacle device on the market. We've been selling AFCI breakers since January of 1997, and have a vast amount of experience engineering and manufacturing the product.

GFCI Failures:

There are two main causes of the failures of both GFCI receptacles and circuit breakers.
> electrical surges
> failure to properly follow manufacturer's instructions for testing

UL has addressed the surge issue by requiring integral surge protection of the devices. As electrical professionals, we need to educate homeowners that they should push their test buttons monthly, and exercise their circuit breakers yearly. Homeowners maintain the mechanical systems in their home, they need to understand what is required to maintain their electrical system. Manufacturers put the test reminder in each GFCI device. I wonder how many of them are put in the loadcenter or at the receptacle?


Reliability:

With over 500 million cumulative hours of operation, the nuisance tripping issue is behind us (I cannot speak to the experience of other manufacturers). What we see when we hear nuisance tripping issues are false grounds downstream, improperly wired three-way switches, shared neutrals, bad wiring in fixtures from the plant etc. These are the types of issues that you would hope the breaker would find.

AFCI/GFCI:

We have the devices available in our warehouse. Whether they are on our distributors' shelves or not is a different issue. Typically, the wholesale industry takes a "chicken and egg" approach to stocking new products. They will not put it on their shelves until customers ask for them.

States issues:

Vermont has taken the high road and amended the code to be as it should be: in all living areas. Arcs can and do occur anywhere, and they realize that. Unfortunately, some states have bowed to the homebuilding industry and have removed this life-saving device because of cost. However, with contractor costs in the $30 range for each breaker, whole house protection can be provided for about $300 contractor cost. Amortized over a 30 year mortgage, works out to pennies a month.

I am passionate about the possibilities of this product, I have them in my home, and as professionals in the electrical industry I would encourage you to put them in your home so you can see and sell the real benefits of electrical safety.

So we require the use of a device that may prevent 40% of the fires as oposed to 60%???

Don(resqcapt19)

Mr. Foley,

Welcome to the group!!!

Very good job on your posted report! Thanks for taking the time to post some information from the Manufacturer's viewpoint.

Please contribute more if you can, or when it's available.

Scott SET

Brendan,

Welcome!
Thank you for choosing to address us here. I see many problems in houses due to the simple replacement of a switch, receptacle or light fixture. It is something that the average Homeowner (or Remodeling Contractor) feels is certainly within their abilities. They just don't realize what problems can be caused by their sometimes poor connections, improper lamping etc. The present DIY boom is not helping either. I think it's a good thing for them (as long as they don't take it too much for granted)


With the present state of the technology, is it possible to manufacture a Circuit Breaker that would protect both the fixed wiring and the portable loads? Does that become much more complicated an issue?

Bill

An AFCI circuit breaker will protect both fixed wiring and connected equipment, however there needs to be a distinction made between parallel and series arcs.

A series arc is an arc fault at a break or gap in a single conductor in series with a connected load or arcing line to ground. Series arcs are difficult to sustain in real life situations, as they tend to “self-extinguish” as the break or gap expands. Also, they tend to be low current since they are in series with a load and also may alert the homeowner of their presence because lights and appliance will operate intermittently.

A parallel arc is an arc from line to line or line to neutral in parallel with a connected load. This type of arcing fault may not “announce” itself, and the load does not limit the available fault current. Parallel arcs are capable of sputtering for long periods of time, and can go unnoticed until a fire starts.

We have not been able to maintain a series arc in the laboratory. Additionally, all of the testing we've done indicates that there will be significant nuisance tripping issues with series detecting AFCI.

The more insidious parallel arcs are those that cause electrical fires. Our circuit breaker AFCI protects the entire circuit from these dangerous arcs, So yes, we have a device that will protect the entire circuit! Additionally, an AFCI circuit breaker will detect and interrupt receptacles that are experiencing glowing contacts, providing another level of protection.

Our industry tends to move very slowly. Luckily for me, my children were born in the day when GFCI is an accepted practice. My four-year-old daughter's life was saved by one of our Type CH GFCI breakers. I had installed a sub-panel to feed an outdoor receptacle, and was in my garage when I heard the breaker trip. Before resetting the breaker, I checked the front of the house and found her with the hose on, pouring water onto an extension cord that I had left plugged into the receptacle. She was standing in the puddle along with the female end of the cord. If this had happened before it was mandated by code, she could very likely have died.

There is an opportunity here for the electrical industry to educate consumers. I’m sure as electrical professionals you feel as bad as I do when you hear of a fire that was started by electrical wiring. And I’m sure you’ve thought that something should be done to stop this from happening. We’ve invested 9 years and millions of dollars to develop a technology to make electrical distribution safer. You now have the ability to do something in your own neck of the woods to make your community a safer place.

Well the largest AFCI i've found is a 60A 2-pole, I am still searching for a dual unit.
If you fella's see any prob with my sub-panel scheme let er' rip...

So you are telling us that you have developed an electronic device that has a 50 to 100 year operational life!! I don't believe that is even possible. What is the failure mode of an AFCI?
Don(resqcapt19)

Don,
how would you know it's a problem without a field tester?

Face it, manufacturer's rule our trade

Sorry Guys,

I really don't get the objections. Even if only some lives are being saved isn't it worth it?
If it was known that the technology existed to prevent some tragedies but it was not required by code I'll bet that there would be a big discussion about 'waiting for body count'

Bill

Brendan,

Thank you for being here. What is the tech of the AFCI? Is the device triggering on rise time, frequency, energy under the curve, waveform, or what? What differentiates the line to line or line to neutral arc fault from other situations that have arcs in normal operation?

Al

The resistance here is basically questioning the rationale, technical specific's & collected statistics behind arc-faults.

This has been the norm for any new product / method handed to the NEC, and essential in it's understanding, hopefully this forum maintains an unbiased approach.

The premis of 'save a few lives' could also be argued in the wearing of steel suits while driving automobiles. If tear jerker stories are needed, brother I got em'.
We loose 50K a year there, but the factors and specifics would be argued hard vs. blind acceptance.

If the NEC chooses an add-a-cycle approach per AFCI's , as it did with GFCI's, then i propose a residential panel and complying main breaker to address the issue.
This would be a european twist, more effective and economical. We hit the upgrades which are the aim (or should be).

Sparky,

Their value has already been proven to the NEC. I see no point in disputing it here. I'm sure that their effectiveness will continue to be under close scrutiny until the next code cycle, at which time there will be opportunity to change things. Until that time I personally am more interested in how they work than in entertaining conspiracy theories.

Bill

Bill,
My questions are really based on wanting to know how they work and if they really will be able to do what the manufacturers have said they will.
Brendan has told us they are really to protect the future of the installed electrical system. Will they have an effective life long enough to provide that protection? Do the have a fail safe function? GFCIs do not fail safe. Brendan has told us that we must educate our customers to check these types of devices. Joe Homeowner is not going to do that on a regular basis. How many of us check and log the results for our GFCIs?
Once the manufacturers can provide a fail safe unit that self checks at a preset interval and has all of the electronics that would normally fail on a low cost plug-in homeowner replaceable card and they have proved that they will be fully effective on both fixed and portable wiring systems, I will support them.
When we push a life safety item that doesn't fail safe and has failure rates up to 58% in lightening areas we are not doing the public any favors. Will the AFCIs do any better?
Don(resqcapt19)

This is in response to Al, I will try to address Don's issues later today or tomorrow.

Arcing faults are not really hard to understand. The thermal and magnetic elements in circuit breakers protect are there for one thing: to protect the wire from being damaged by excessive current.

The thermal element is a bimetal that provides overload protection to keep the amount of continuous current below the level that the wire can safely carry. #12 = 20 A, etc.

The electromagnet protects against short-circuits and is commonly called the instantaneous trip. However, the use of the word "instantaneous" is a bit misleading. Breakers must allow for motor inrush currents, which can be 6-10 times full load. So, a 20 amp breaker needs to be able to ride through temporary high currents up to 120 or so amperes so that they do not nuisance trip. At extremely high current levels 800% of handle rating and greater, the breaker trips in less than a second.

In a typical home, the available fault current downstream from the loadcenter is very low ~ maybe 100 amps. So, what happens when you when you get a break in the insulation is that you get short, low-current level arcs. The arc is not present long enough to trip on thermal, and it is not of a high enough magnitude to trip on instantaneous. However, the plasma arc can exceed 6000 deg. C., and explode molten copper as it arcs.

In order to see that this is happening, we analyze the current waveform and look for the spikes that indicate that there is an arc. We sample for about 8 half cycles, which is a long enough period of time that we ride through normally occurring arcs. So basically, we will see the arc, then keep sampling for a given period of time, and if we see the arc there again, we de-energize the circuit.

Hope this helps explain what the product does. Let me know if you have any other questions.

-Brendan

Quick note to Sparky:

I feel pretty certain that there is not a 60 amp, 2 pole AFCI. There are 60 amp, two pole GFCI breakers, but no AFCI of which I am aware.I believe that Cutler-Hammer is the only manufacturer with a two-pole, and we stop at 20 amps.

There are actually 2 different two pole AFCI available. One is a standard 240 volt, 2-pole, and the other is what we call a 2 pole independent trip (AFIT). It allows for AFCI protection on circuits that contractors refer to as “multi-wire,” “shared neutral,” or “home run.” These are two individual 120-volt circuits that share a neutral. The AFIT is a two-pole breaker with two independent 120-volt circuits. The breakers trip independently on overloads or short circuits, but trip in common on an arcing fault. For contractors that use 3-wire circuits this is a huge labor savings over wiring two individual 1 pole breakers, and it will allow them to continue this wiring practice.

Don,

I agree with wanting to know how they work and how reliable they are. I will be on the 'Front Lines' myself trying to explain to the customer what they are and why they are required. I will also be explaining that nothing is 100% guaranteed and it is by no means meant as a substitute for safe wiring practices.

I don't think that there should be any question as to whether they should be required at the present time. We have many safety and potentially life saving devices that are only partially effective. We still use them though in the hopes that it may work this time. As far as the testing goes, it's important that the public be educated about that.

Bill

[This message has been edited by Bill Addiss (edited 12-05-2001).]

Bill,
I think there are a lot of reasons to question the installation of AFCIs at this time.
1) I'm not convinced that they will function to stop the fires that the manufacturers say they will. They say they only work effectively on parallel arc faults. I've always been taught that 90% of electrical failures are at connections. This would be a series fault, not a parallel fault.
2) The fire statistics used to get these items into the code are faulty.
3) If they aren't fail safe they shouldn't be permitted on the market.
4) If they don't self test they won't work when needed. The average homeowner won't test them.
6) I'm glad I don't do any residential. I see a lot of potential liability for the contractor when these things don't work and there is a fire.
Of course once the code is adopted in my area I will support the use of AFCIs. Until that time I will continue to question the requirement until I'm convinced that they really work as advertised.
Don(resqcapt19)

Brendan,

Thanks. . .this whets my appetite. 8 half cycles, all one side of zero volts, or 8 half cycles equal to 4 full cycles?

Is that half cycles of just current? Are you sensing with a current transformer?

Is a snapshot or other representation taken of the suspect arc to compare with the next arc that would initiate the Interrupter? Is the "memory" longer than 8 half cycles, and if so, how much longer?

Is there a threshold level of arc activity that is tolerated, and what are the parameter(s) of that level?

Please don't hold back, gimme both barrels. The information I have been able to glean has been helpful, but not specific enough. I entreat all the hard tech you can post!!

http://www.zlan.com/afci_c4.htm

After looking at a website of the manufacturer of a competitive product, I'm even more skeptical that the AFCIs will prevent the fires that they are advertised to. The other company says that most of these fires are caused by "glowing connections" and that AFCIs do not detect "glowing connections". Their device is a temperature sensor type item that installs at switches and receptacles and opens the circuit when the temperature exceeds a preset point. They say that these "glowing connections" are caused by high resistance at a point of connections and have studies that show that the copper can glow red hot with as little as 0.3 amp load. They claim that these connections do not create an arc signature that the AFCI can detect. http://www.fire-fighter-products.com/index.html

Sparky,

Thanks for the reference. I noted it earlier when you provided it in another thread, printed it out and went over it. That too whets my appetite. ZLAN's site contains the most tech I've seen yet, but it is just to the side of clear for me. . .I may be thick, but it seems that the core of an AFCI is waveform recognition, either current, voltage or both. What I don't understand is the implementation of the hardware solution.

Brendan,

Maybe you have access to CH's waveform analysis? What are the identifiable characteristics of the class of faults the AFCI triggers on, and how does the (presumed) logic in the trigger discriminate between arc waveforms of varied "flavors". Am I even asking the right question here? Or is the answer to the question a trade secret that each manufacturer is keeping under wraps for the time being?

Respectfully,

Al

In recent posts someone installed AFCIs in a brand new residence, and had problems right off, and finally he said he had to remove them because of the nuisance(sp) tripping.
My question is this if in a 3 bedroom house, figure 5 receptacles each, lighting outlets etc and there is a problem which happens to intermittant how do you find the problem, short of replacing or rewire-nutting all the units, checking all switches for arching, and if switches can cause an AFCI to trip, I am not saying it can, but if its suppose to trip on arching, then it would make sense.
I know backwired receptacles are notorious for arching and then welding themselves back together again, or until the wire burns itself off completely.
Also does anyone know why Smokes are to be wired to the AFCIs ?

Don,

I'll try to answer your numerous questions, although I'm not holding out any hope at convincing you...
______________________________________
So you are telling us that you have developed an electronic device that has a 50 to 100 year operational life!! I don't believe that is even possible. What is the failure mode of an AFCI?
Don(resqcapt19)
________________________________________

I don't believe I ever claimed that we had developed an electronic device with a 100 year operational life. What I said was that homes do not stay new, and that the panels in them are there for longer than the wiring is safe. Of course all electronics in homes would last longer with proper surge protection as IEEE recommends. Until it becomes code however, I don't expect that the industry will embrace surge protection as it should.

When you ask about the failure mode, I assume that you are asking what happens if the electronics go bad from surges. If this happens, the breaker will not trip when the test button is pressed, and the instructions are to replace the unit. This is the same as GFI breakers and receptacles, and obviously the key is to educate consumers on proper electrical maintenance. We maintain furnaces, gutters, woodwork etc. It's not too much to expect homeowners to push the test button. All that needs to be done is to give them the instructions that come with the unit rather than throwing them away. If they don't maintain the product, at least you've done what you can to provide a safe electrical system.

There is a bit of contradiction in your asking for a self-testing device while asking for an inexpensive unit. The reality is that we know that we cannot make these too expensive, or they will not be used. A self-testing AFCI or GFCI may be down the road, but it is cost-prohibitive at this time. If contractors are unwilling to spend $30 for an AFCI, I can pretty much assure you that they won't spend $60.

__________________________________________
1) I'm not convinced that they will function to stop the fires that the manufacturers say they will. They say they only work effectively on parallel arc faults. I've always been taught that 90% of electrical failures are at connections. This would be a series fault, not a parallel fault.
___________________________________________
I'm not sure what we will have to do to convince you that these are viable devices that will stop fires. There are a great number of folks that have studied the technology and have determined that it will save lives. The code making panel consists of every facet of the industry, contractors, builders, academia, etc. There is only one member from NEMA (National Electrical Manufacturer's Association). The process is there to keep any one body from dictating what gets through to the code. It is an arduous process to say the least, and a very important one. Without an electrical code, there would be virtually no new safety products developed. Manufacturers would not spend the money to develop new products unless the benefits could be mandated in some form or fashion. UL has a standard, CPSC and others have come out in favor of the technology, obviously it has been proven to folks that have analyzed it, so at some point you'll need to have some trust in the experts in your industry that represent you. For more on arcing faults from UL, go to http://www.ul.com/about/otm/otmv5n3/labdata.html.

_________________________________________
2) The fire statistics used to get these items into the code are faulty.
_________________________________________
The statistics that were used were from CPSC, the insurance industry and fire authorities. I'm not sure where you believe that better statistics exist, but if you know of any, I'd be happy to take a look at them.

_________________________________________
3) If they aren't fail safe they shouldn't be permitted on the market.
__________________________________________
Then you would continue this argument by stating that we shouldn't have GFCI, smoke detectors or sprinkler systems? All are not fail-safe.

Another issue that I would like to address is the glowing contact issue, and your use of Fire-Fighter products as a reason to question AFCI technology. First, our AFCI breakers are not only UL1699, but they are also UL 1053 for equipment ground fault protection, and will prevent the glowing contact phenomena. I find it ironic that you support the position of an unknown company like Fire-Fighter, but will not support the position of the company that invented the circuit breaker, and has more Ph.D. electrical engineers designing true world-class products.


Someone mentioned doing it the European way. Europe does not have whole house AFCI, they have earth leakage. Actually, some of the IEC manufacturers are looking at AFCI technology because of the problem they have with burning appliances. Europe does not have appliances that are as fire-resistant as the U.S. due to the environmentalist influence keeping chemicals out of the designs. They have a real problem, and they may soon turn to our technology to solve it.

I will try to answer Al and Motor-T over the weekend or late next week. I have to go try to sell some Arc Fault Circuit Interrupters next week.

Brenden,
Thanks for addressing my some of my questions. I'm not really trying to be a pain in the ***, but have real concerns that these devices do what you and the other manufacturers say they will. I don't doubt that they will clear the arc faults that you claim, I just don't think that those faults are the cause of very many residential fires.

I don't believe that homeowners test their GFCIs and don't think that they will test the AFCIs. Again I ask how many of you out there reading these posts regularly test your GFCIs. I know that the ones in my house are not tested monthly as required by the instructions.

I'm not saying that there are better statistics, just that there is a "when in doubt, its electrical" mentality in the fire investigation process. Very few fires are investigated by people with any real knowledge of electrical systems. Even where the cause of the fire has been correctly identified as electrical, there is no detailed information available as to the exact type of electrical fault that caused the fire. Some of the data submitted by Mr. Clarey of Cutler-Hammer in comment 2-68 in the 98 ROC says that 36% of the home fires were started by the fixed wiring system. This is not broken down into the exact types of fires. His comment goes on to say that AFCI breakers could be expected to prevent 40% of these fixed wiring system fires. Now we are down to the AFCI breaker being able to prevent less than 15% of the home fires. Data from the US Fire Administration's National Fire Incident Reporting System (NFIRS) which is used by 140,000 fire departments in 40 states shows that the home fire loss caused by electrical fires is only 13.75 of the total loss and the loss caused by the fixed wiring systems is only 5.5% of the loss. The fixed wiring system loss included all of the fixed wiring within the walls....junction boxes, lighting outlets, receptacle outlets, distribution panels and the wiring between these connection points. There is nothing in the data that tells us how many are parallel faults and how many are series faults.

I don't believe that very many of the fires are originating in the conductors between outlet points. Can you please describe the types of faults that will create parallel arcing between outlet points? I can't think of very many things that could make that happen. I can't think of any type of parallel fault that could occur between outlets in a code compliant wiring system that would not be cleared by a GFCI. Can you list some parallel faults that occur between outlet points that won't be cleared by a GFCI?


The engineers who did the study in Japan that is cited on the Fire-Fighter site had no trouble making these "glowing connections" occur. Are you saying that a glowing connection is not an arcing condition? Is a glowing connection a series arc? Are you saying that a fire cannot be started by the heat produced by a faulty connection? I'm sure that all of us who have done any service work have seen the melted parts that have been caused by a poor connection. Are you down playing the hazard of series arc at points of connection because the AFCI breaker won't detect them?

Just because you have lots of good people and are a well respected company doesn't automatically mean that you are right. Edison made that statement that AC current was only good for powering electric chairs. He made this statement based of both what he believed to be technically correct and because his company only produced DC equipment. I didn't say that I would support the Fire-Fighter product, just that it has led to more questions. As a matter of fact, I have even more reservations about that product then I do about AFCIs.

If AFCI breakers can do it all, why did one manufacturer of AFCI breakers submit a proposal (proposal 2-111, 2001 ROP) that would have required both AFCI breakers and AFCI receptacles? The fact that this was done also makes me question the AFCI requirement.
Don(resqcapt19))

[This message has been edited by resqcapt19 (edited 12-09-2001).]

I’ve been monitoring this post for the past week. Lots of good information thanks to all who post.

rkukl;
I've been reading with great interest too

motor-T;

In review, the 96' NFPA 72 2-3.24, will not allow a residential smoke(s) off a GFI.

Perhaps smokes were not considered in the 11th hour revisal of 210.12 to stipulate 'outlets' instead of receptacles.

I've also been following this with interest, but keeping fairly quiet as I've not had any experience of these devices.

Brendan,
Are you aware of any AFCI being exported to or manufactured in Europe? There's no sign of them in any British manufacturer's range as yet.

Re: Test buttons,
I've found that the majority of people here have no idea that their RCD/ELCB (GFI) even has a test button. I always try to explain, but I doubt most of them go on to test even once a year.

Personally, I'm obsessed with testing GFCI's before I use them...

It's just something I've always done... Since 1976 when my Mom bought the double wide with the funny outlets...

Before I became an electrician, I didn't even realize I was doing a good thing! I was just curious about how it worked...(poke-pop!-heh heh heh... repeat)

I can't speak for anyone else and I am probably the exception to the rule...



[This message has been edited by sparky66wv (edited 12-13-2001).]

I have read these posts with a great deal of intrest. Since use of the AFCI breakers- made by your company Brendan- cost me over 45 manhours in callbacks, replacing the 5 ea AFCI breakers in the house twice,(total 15 AFCI breakers),a new hair dryer for mrs homeowner, 5 single pole 20 amp breakers, and a lost customer who I have known for 15 years. Untill I see proof that these devices work and will prevent fires by at least 15 years experience, I will NOT ever warrent them in my company.
The supply house and local rep refused to replace the breakers or refund the money I paid for this junk claiming lightning caused the problem, even though 1 set or breakers failed without any storm in the area.
To say I am angry is correct.
I understand what you and many others are trying to do. You are trying to improve safety in electrical installations. But I must agree that the average home owner will NOT test every month- They do not test GFCI outlets in plain sight. What makes you think that they will open the panel cover to test a breaker then have to reset the alarm clock by the bed? What about apartment dwellers- most of whom could care about maintence less?
It is my belief that the primary reason the AFCI breakers are in the code is so the manufacturer can recoup there R&D costs and make a profit. If this product is so great sell it on its own merits. Do not force it down our throuts legally when the 02 code is adopted.

The stat's collected and presented as validation exemplify the old addage.

House fires do not recieve the forensic's of airline crashes. There are few, if any extensive investigations. Most do not even warrant an investigation at all, so an educated quess by the firechief, or deputy goes unquestioned.
Even if said fire WAS electrical in nature, the factors involved are rarely pursued, i.e: was there a bona-fide electricain? was there a permit? was there an inspection done? Was there any DIY'er involvement? The standards vary so much from locale to locale that a generic compiling does this no justice.
The insurance industry simply pays off, and the matter is dropped & Our trade is held to blame
Yet manufacturer's will use this info , and grab the public by the lapels by advertising firefighters haulin' little girls out of burning buildings in our trade mags!

sparky
former FF, .......bark worse than bite

Brendan,

Hope your week has gone well. I'm sure that you have discovered that the audience here is critically astute and looking for precise information about your product. So much of what has been available out in the trade journals, in my opinion, has the flavor of hand waving of a math proof where one or two steps are glossed over by the professor.

Perhaps you can explain a missing step or two. As most of us are dealing with AFCI installations, we want them to be durable and dependable for what they do, so that John Q. Public may have a quality experience of life and electric power and we can move on to the next installation with out looking back.

In addition to the questions in the thread above, please tell us about the AFCI microprocessor, how is it protected from the harsh environment it services? Are there any concerns about needing to change the microprocessor's read only memory of criteria for interruption? And, if so, would this be done to the installed product, or is it, once installed, unsupported?

Respectfully,

Al

I apologize for my lapse in replying. I have been traveling and attending to my more than full-time job!

I will try to take a few moments to answer some questions. For some of the more technical questions, I am going to our design engineers, and at this time of year many folks are taking needed breaks.

For ElectricAL:
The AFCI continually monitors the voltage. We monitor the voltage trace waveform across the resistive element in the breaker. We monitor the voltage drop and convert to current. We are looking for the spikes in this waveform that are indicative of arcing faults. When we see that there is evidence of an arcing fault of 50A RMS or greater, we analyze the current waveform for the signature of an arcing fault. If we see this, the breaker is "armed". We then look for 8 arcing half cycles over the next 1/2 second, (these do not have to be consecutive half-cycles, and they can be positive or negative. If we see 8 half cycles of arcing, we trip the breaker. If the electronics does not see 8 arcing half cycles in that time, the breaker is no longer armed, and goes through the process again. All of this is done with a custom analog integrated circuit. Additionally, we monitor arcs to ground for the parallel arcs in NM-B cable at a 30-mA level. There are MOV's on the board to protect from surges. Hope I've answered your questions.

For Motor-T and Sparky:
Smoke detectors would be covered by the changes made to 210-12 for the 2002 code that changed the word "receptacles" to "outlets".

For pauluk:
We are beginning discussions to export the technology to Europe in the IEC breakers. There is a problem in Europe that the appliances are more flammable over there due to the fact that Euro manufacturers do not use as many fire-resistant chemicals in their plastics due to concern over the environment. Someone earlier stated that they do AFCI in Europe. That is a misstatement. European standards use earth leakage, which is not AFCI.

For nesparky:
First, I apologize for your difficulties. I would like for you to email me directly at BrendanAFoley@eaton.com with your location, and the distributor and sales office that you were dealing with. I need to let them know that they are not following our "no-quibble" warranty process. In the same email, I'd like you to send your name and address so I can have the Cutler-Hammer sales engineer get in contact with you.

You did not provide a lot of details about your problems, whether the five breakers were all replacements on the same circuit or not. If you email me directly, I can go through this in more detail. I cannot be sure until we talk further, but I would suspect one of three things was causing the circuit breakers to trip:
1) There was ground current in the circuit. This could be because there was a grounded neutral somewhere in the circuit.
2) There was a shared neutral in the circuit.
3) There was arcing in the hair dryer.

The vast majority of the "defective" GFI breakers that we receive back have no problem whatsoever. We test the devices, and they test within design parameters…that is, they are functioning properly.

To all, I will try to do a better job of replying in a more timely fashion. I know that you have concerns, and I will try to address them.

Happy Holidays,
Brendan Foley

Brendan,

Thanks for the info. I guess we'll start seeing AFCIs over here within the next few years then, although I expect they'll be given a different name, as with GFCI/ELCB/RCCB/RCD.

A few days ago I think someone (Sparky?) mentioned the possibility of using a single AFCI as a sub-feed to several regular breakers to minimize costs.

We already have whole-house GFI set-ups here (and elsewhere in Europe), and I have to say that I don't particularly like the approach. It can be a real pain when an earth fault on one ciruit knocks out power to the whole building.

What sort of price range are we talking for a single-pole 15 or 20A AFCI compared to a similar GFCI?

Paul,
I concur with your thoughts on whole-house AFCI and earth leakage. It would be like trying to find a needle in a stack of needles!

AFCI's retail in the US for about $30, or roughly the cost of a GFCI breaker. The key to getting the costs down is to get the volumes up. Until the contractor community buys in, and starts installing them in installtions that do not require them by code, the cost will never come down. Code right now mandates for bedroom circuits in new construction. There are 1.5 million new homes built a year. With 3 circuits per bedroom, that's only 4.5 million circuits divided among 4 manufacturers. That is not enough volume to drive down the cost of the electronics.

The irony, of course, is that the homes that need it the most (older homes with old wire) will not have to have it by code.

Brenden,
The local hardware store has your AFCIs on the shelf at $79.95 ea.
Don(resqcapt19)

And they may sell one at that price, but I doubt that any electrician will pay that price. Is it a chain, or a mom and pop? I was in the Home Depot here at lunch, and they were $29.99.

The market price will begin to settle down once wholesalers and retailers begin to sell them. How many $90 smoke detectors have you bought lately?

I don't think that the hardware store will sell any at that price. $30 is a much more reasonable price and comparable to GFCIs. I haven't checked any supply houses as I don't do residential work.
Don

Brendan,

Thanks, this is helping.


Can you tell us about the process of the waveform analysis and the nature of the "signature" of the arcing fault?

Al

They may sell one to a Joe Homeowner, but that's about it.

The waveform analysis compares the arc signature (the shape of the waveform anomaly to the hundreds or thousands of arcs that we've mapped in the laboratory. Basically, we analyze the curve and see if it is a non-operational arc...that is, an arc that shouldn't be there. I will paste below a short dissertation from one of our senior engineers on the parallel/series issue. I hope this answers more questions than it generates. :-)

Q. Why was the AFCI designed to sense a short-circuit across two conductors, and not a single open arcing conductor?

A. Arcs between conductors are sporadic (pulsing)in nature. For dwelling unit circuits, the rms available current at an outlet prior to a fault is typically 75A or higher. The arc voltage further reduces the circuit current and, in combination with the intermittent current waveform, the fault current is unlikely to trip the circuit breaker instantaneously (trip level about 200A rms) and possibly not even thermally. The safety enhancement of the AFCI is to recognize the presence of these high energy arcs, and to cause circuit interruption (trip the breaker) far more rapidly than would be the case with a conventional circuit breaker. The UL1699 tests are performed with both NM-B and two wire SPT-2. The focus has been on high current "parallel" arcs rather than low current (load limited) "series" arcs because:
(1) they are higher energy arcing/fire sources
(2) they are far more likely to occur (it is very difficult to maintain a low current series arc between copper wires at 120V)
(3) it is possible to detect parallel arcs without nuisance tripping. Here it is noted that low current safe arcs are an everyday occurrence in dwelling units (switches, thermostat controls, electric motors etc.). Further, many low current electronic-appliances have chopped waveforms (drills, ballasts, power supplies etc.). Thus low current unsafe arcs (at a single open conductor) have to be distinguished from low current safe arcs, and other naturally occurring waveforms, without causing nuisance tripping.

Q. Could the breaker be designed to sense a single arcing conductor? Would it still be called an Arc-Fault Circuit Interrupter?

A. The Branch/Feeder AFCI responds to "series arcs" in NM-B. The test is in UL 1699. In practice, manufacturers utilize the fact that NM-B contains a bare ground conductor. Any break in a single conductor causes current leakage to this ground wire, and the AFCI opens the circuit prior to the arc burning through the NM-B insulation. Since leakage to ground is the response criterion, downstream switching arcs do not cause nuisance tripping. Again it is noted that a series arc in NM-B is highly unlikely.
UL1699 contains an AFCI "Combination" category. This category includes series tests in SPT-2 as well as NM-B. The series test demands that the arc interrupt after 200 to 1000ms (12 to 60 cycles) depending on the current (15A to 5A). In particular this time interval allows discrimination between "operational arcs" (e.g. switching) and "unsafe arcs". There are no commercially available Combination AFCIs.

Q. What was the reason the NEC decided to require AFCI in bedrooms only?

A. NFPA fire statistics show that a high percentage of electrical fires occur in bedrooms. There are all manner of appliance cords in bedrooms (for example, radios, clocks, blankets, air conditioners, heaters, TVs, vacuums) and also lamp cords. All of these cords can be trapped/abused leading to line to neutral arcs. Further, there are long runs of installed wiring (NM-B) between the loadcenter and the bedroom outlets. These runs can abused during installation (e.g. stapling) and after installation (driving nails into the wall etc.).
Summary
The present Branch/Feeder AFCIs provide a significant enhancement in fire safety. They guard against parallel arcing faults in both the installed wiring (NM-B) and the two wire extension wiring (SPT-2). In the unlikely event of a series arc at a break in NM-B, the arc will be interrupted by the AFCI responding to ground current. The overall device is immune to nuisance tripping.

Brenden,
Can you cite examples of how these parallel faults occur in the fixed wiring system? And also why the AFCI manufacturers think that most fires that occur in the fixed wiring system are of the parallel type? This area is the whole basis for my objections to AFCIs. I have been taught and believe that the vast majority of faults that occur in electrical systems are at the points of connection. Faults occurring at the points of connection are of the series type, if they are even arcing faults. Are faulty connections series arcing faults, or just high resistance connections that produce a lot of heat?

By Combo AFCI's is dual AFCI/GFCI function implied?

Does this mean Ul1699 lists AFCI's for NM w/ground only? and older circuits would not be listed for use?

Our wiring methods in England are slightly different of course, but I have to go along with the general consensus that the majority of arcing faults are series, not parallel.

I see evidence of arcing and overheating from wires loose in a terminal, from worn contacts in low-quality switches, etc. -- All series faults.

By contrast, evidence of parallel arcing is quite rare. Most parallel faults I see are where someone drills/nails/screws straight into a cable and the damage is immediately apparent.

The one type of parallel fault that I do see more often is a trapped hot wire behind a fixture, the insulation deformed and cut through to the point that it shorts to the metal box. In most such cases, the direct short just trips a normal breaker or blows the fuse immediately.

I'll concede that in a non-AFCI & non-GFCI circuit such parallel arcing to ground could cause a fire, but it would be interesting to know if any data are available to show whether a sensitive GFCI is any less effective protection in this instance.

Obviously the GFCI wouldn't help against a hot-neutral arc, but again it would be interesting to know if there are any figures to show what proportion of parallel arcs are hot-neutral rather than hot-ground.

A couple of other points strike me from the engineer's report posted by Brendan. It suggests AFCI should be required for bedrooms due to the amount of appliances and cords in use. But with the exception of an electric blanket, surely everything metioned is just as applicable (if not more so) to the rest of the house?

Just one more thing (with apologies to a certain well-known detective!). If we acknowledge that a potential between-outlets fault in NM cable feeding bedroom receptacles needs AFCI protection, then what about other cables in the same wall feeding outlets on the other (non-bedroom) side or just passing through on route to some other part of the house? Shouldn't these be AFCI as well? Just a thought.

I'm all for anything which aids safety, and as someone who has no practical experience of AFCIs I have no axe to grind either way: I'm just trying to look at all the pros and cons with a critical eye.

Paul,
I think that the bedroom was picked as a starting point because more dwelling unit fire fatalities occur in the bedroom then in the other rooms. However, the point of origin of these fatal fires is in fact often in other rooms of the house.
Don(resqcapt19)

Don,

"More people die in fires in the bedroom so that's where we'll start with mandatory AFCI" seems a very simplistic and flawed approach.

I would've thought that more fatalities occur in the bedroom simply because someone has to wake up before he realizes there is a fire. By that time, the blaze has well and truly taken hold and maybe even rendered its victim unconscious before he has a chance to waken.

As someone involved with the aftermath of fires, would you agree with my logic?

Paul you are correct. That is the very reason that smoke detectors are required in most areas for dwelling units. Unfortunately many times after a fire, the detector is found without batteries. This is a reason why some areas now require dual (utility and battery) powered detectors. I fully support these requirements and would also support the AFCI rule if I am convinced that they will prevent a significant number of fires. It does not appear to me that the AFCI can do that at this time.
Don(resqcapt19)

I am having engineering review my technical reply, hopefully sometime tomorrow. In the interim, our AFCI devices are both UL1699 (AFCI) and UL1043 (equipment ground fault).

Obviously, arcs can occur anywhere in a home wiring system. Anything I say about why the code making panel chose bedrooms woult be speculation since I wasn't there. The fact that most people die in bedrooms had something to do with it, but I'm sure that consideration was given to the nature of wiring in a bedroom, and the types of devices that are used. By that I mean that many bedrooms have large furniture against the wall such as headboard, dresser, chest, nightstands, etc. Therefore, it is more likely that wires would be abused by having the furniture pressed up against and bending the wire. Also, unlike standard lighing loads, the loads may tend to be more continuous such as alarm clocks, telephones, air cleaners, electric blankets, etc. Therefore, the loads would be running while people are sleeping. Just a thought.

Sorry...UL1053...finger slip

For NM-B, with ground, the device will trip on ground fault.

Brendan,

I'm beginning to realize that the AFCI (at least from what I gather from the above tech) is intended to operate on a narrower set of fault conditions than I had assumed earlier.

Don(resqcapt19) describes the "glowing connection". I've seen far too many heat destroyed connections. Connections whose conductive metal to conductive metal resistance is not as low as it should be. When current flows through the connection, current supplying a legitimate down-stream load, the watts of heat released in the connection will be the current squared times the resistance. This heat moves out into the surrounding metal and insulations at a rate determined by their physical properties. The parts "fill up" with heat with gradual temperature rise because much of the heat is able to move on into air and other surrounding materials. But, at a point, the parts are "full", and if more heat is being created in the resistance of the connection than can be sloughed off into the surround, the temperature of the connection starts shooting up extremely fast. Physics calls this point the Black Body Radiation Limit. Our real world connection gets to this limit quicker than the theoretical. The connection "glows" at circuit normal load current levels. High temps are attained that result in destruction of the connection that creates the heat that generates the high temps. Circular, huh? At some point the connection may so degrade as to result in contact with either ground or the other side of the circuit, and there is a parallel fault or a ground fault that the AFCI can "see". Up to this point, the AFCI is blind to what's happening. Am I right? This is in a dwelling bedroom with 15 or 20 amp overcurrent branch circuit protection, a load that might be a space heater, and the AFCI starts "looking" above 50 amps, so the connection that is glowing, where ever it is, cord and plug contacts, wire nuts, terminal screws, hot or neutral, remains invisible while heat is released.

Do actuarials exist for this scenario?

The statistic about %50 of the GFIs failing, I believe that was in the IAEI magazine a couple of years ago. The next month they came out and pretty much disowned the writter and the article itself. Of course, there could have been another source with the %50 number, I don't know.
Don

A senior research engineer at UL has made the following statement.
"...For example, electrical ignition most frequently occurs as the result of Joule heating or electrical arcing. It should not be expected that those ignition scenarios representing Joule (I^2R) heating would necessary be prevented by an AFCI..."
The complete statement was published in the IAEI News. It is available at: http://www.ul.com/regulators/afci/Dini.pdf

This seams to support my point that many electrical fires are caused by poor connections and AFCIs do not detect these types of faults.

Don(resqcapt19)

indeed....
Mr. Dini performs an amazing run of interference for UL. The sanctioned widget of the century may well turn out it's edsle.

After reading the article when it came out i contacted UL , asking if AFCI's were listed for ungrounded circuits. This was not a 'if it'll work' question,or 'do you think it's a good idea?' question.
It was a listing question, as it IS or it IS NOT listed for such use.
UL's reply did not resolve this.

First,let me identify myself as a lobbyist for the Michigan Association of Home Builders. I deal with code and land use issues.

From this perspective, one of the real problems with the code development process is the ability of manufacturers to use codes to create a market for their products.

That is precisely what happened with arc-fault circuit interrupters.

Those of you who are properly skeptical of this claim can go to http://www.holmesreport.com/holmestemp/story.cfm?edit_id=1176&typeid=4

which outlines the specific public relations and lobbying efforts used by Cuter-Hammer create a market for their device by creating a code requirement in the NEC and a corrsponding "consumer pull."

I wonder what happened to Brenden from Cuttler-Hammer. We need a manufacture's rep to help answer the questions.
Don(resqcapt19)

Hello Lee.
an interesting article, yes, but i must point out that the trade mags have been full of Arc-Fault ads for years now.

Most here are well aware of how the NEC is lobbied, as well as manned by special interests, all who would simply turn to the first few NEC pages can see this.

I would also like to point out that those who seek factual analysis as to the glorified widget's efficay should not be branded as nay-sayers here, anti-safety, or other label because we question the 'safety biz' as applied to our livelyhood.

Please show me series vs. parrallel incidents here.....as a colletive statistic from electrical fires.

Please show me the 'series' vs. parrallel related incidents here.....as a collective stat from non-fire related incidents
(i.e.-what this trade see's day-in, day-out...)

Show me the facts, & i'll be a believer that will pass this on. As a contractor we will constitute the largest 'end sale' for any new market. Put yourself in a contractors shoes and imagine yourself selling arc-faults. Better yet, hanging your good name on thier performance.
Catch yourself saying.....

It WILL prevent electrical fires ma'am, just like all the ad's say....

And you will forever be held to this, while the CMP's, NEC, and inspection community can claim immunity...... YOU MADE THE SALE!

Likewise, put yourself in a customers shoes,
would you be sold on a 'maybe' product? , hey i'm talking a dozen of these @ $30 a wack here........

conversly.....

would you be a tad upset if you found someone selling you on false security?


Show me replies like this;


........and any electrician worth his salt has the right to skepticism.



[This message has been edited by sparky (edited 01-23-2002).]

Me to.