I finally looked up NRTLs a while ago - surprised how little info was out there.
As far as OSHA is concerned, the standards come mostly from UL, a few from old lab Factory Mutual, and some from IEEE. Standards may have all been accepted by ANSI. Standards didn't come from the new NRTLs. Not obvious what states require.
Is much equipment appearing from the new NRTLs?
Wonder if there will be combination AFCIs by then.
U/L is the defacto US NRTL and most people assume they make the rules but as we start seeing more things coming in from other countries that are not US trademarked I expect to see more from TUV. ETL is planting ads in the trade rags reminding people that their listing mark is the same as U/L At a certain point I start to see these testing labs and standards orgainiztitions taking on a life of their own, becoming more odious than the governments they are attempting to replace. I think AHJs should get in the habit of skipping cycles in the code, just to cut down on the churn. Most AHJs and government regulators have not really evaluated and adopted one cycle before the next one is in "comments". That is how we get cases where they adopt a code and get bushwacked by something nobody really understood. (like 682.33) NFPA is already taking proposals for the 2011 and most people have not seen the 2008 yet. That is ridiculous.
Applause on what you said. NRTL's are evaluated using a ANSI standard ANSI Z34.1 - 1987 the last time I checked, but that was about 1996. This standard was how the State of Alaska determines if an applicant can be a NRTL.
I look at adopting the 2008 NEC as - well it is not perfect, but we should try to live with it and help support the many people that make it possible. They try very hard and work very hard to produce a fine safety standard for us and I think we owe them our support. A backlash could potentially lead to a financial crisis at the NFPA.
In alt.engineering.electrical Gerald Newton wrote: | On Oct 10, 4:28 pm, snipped-for-privacy@aol.com wrote: |> On Wed, 10 Oct 2007 18:00:35 -0000, Jerry |>
|> wrote: |> >CPSC, Schneider Electric North American Division Announce Recall of |> >AFCIs |> >WASHINGTON, D.C. - The U.S. Consumer Product Safety Commission |> >announces the following recall in voluntary cooperation with the firms |> >below. Consumers should stop using recalled products immediately |> >unless otherwise instructed. |>
|> >Name of product: Arc Fault Circuit Interrupters (AFCI) |>
|> >Units: About 700,000 |>
|> >Manufacturer: Schneider Electric North American Division, of Palatine, |> >Ill. |>
|> This is 3 years old but I do wonder how many they have actually |> recovered. If it is 40% I would be "shocked". | | I was unfamilar with this recall until you brought it up in a previous | post. Absolutely nothing was said about this at the NW IAEI Section | meeting that I attended in Anchorage during the first week of | September. | With 700,000 units out there, it is a real problem as you explained in | your post. I am creating my 2008 NEC Change course and have been on | this AFCI thing for three days. | It is interesting to note that at the Sq D site they explain that they | are working with vacuum cleaner manufacturers to insure their products | do not trip afci's. | Can anyone imagine how many new products are going to have to go | through this same evaluation. I suppose that we can expect increased | costs for the evaluation of an electrical product to insure that it | will not trip an AFCI. Is this going to part of the listing | requirement for new products or does anyone have a handle on this at | all? It looks like a bucket of worms to me. I just talked to an | electrician in Hawaii that told me that some types of computer | monitors are tripping afci's.
Maybe they should have considered all these appliances when they designed these AFCIs. The arc waveform of a motor (I'm guessing typically these are universal motors with brushes that arc) is not the same as the arc waveform of a loose connection. But just how well the tiny bit of software they can put inside a breaker can make the distinction within a cycle of power is another issue.
How about a device that is specifically designed to filter out the arc waveform that can be incorporated in new appliances? An LC low-pass?
| Hmmm, does anyone know what it costs to fly out to the Yukon River to | replace a AFCI? Most of these villages do not have an electrician.
I would hope you would.
| The more I research the AFCI circuit breakers the more evident it | becomes that more R&R should have been done. | | Quest 1: Did the inventors test every electrical apparatus that is | used on 15- and 20-ampere 120 volt circuits in dwelling units that are | on the market today? | Answer: NO | | Quest 2: Did the inventors test every electrical apparatus that is | used on 15- and 20-ampere 120 volt circuits in dwelling units that are | in use but no longer on the market? | Answer: NO | | Quest 2: Did the inventors test every electrical apparatus that is | used on 15- and 20-ampere 120 volt circuits in dwelling units that | will be available on the market? | Answer: NO | | Apparently, these devices are being forced into homes by new rules in | the 2008 NEC while they have not been fully evaluated. | The future decisions now require that either the manufacturers develop | only those products that have waveforms in the set of waveforms | accepted by AFCI's or the AFCI's be reprogrammed to any new waveform | signatures that new products may have | | I am seriously thinking about writing a letter to the State of Alaska | suggesting to not adopt the 2008 NEC without and exception to | 210.12(B).
I would suggest, instead, to add a "variance" that allows substitution of a non-AFCI breaker in cases where a definite problem exists. To qualify for the substitution, a letter must be sent to a central authority for record keeping (maybe the state inspection board) and the manufacturer of the breaker to detail the situation, including a description of the device found to be causing false trips. The rule should also require replacement of certain classes of bad devices, such as a light switch that happens to not part the gap fast enough and arcs more frequently than it should.
I remember as a kid I could "play" with the light switch and get the lights to be at half brightness. I usually heard the "sizzle" inside the switch, but then didn't think of it as an issue. Today, if I _CAN_ do that with a switch, the switch gets replaced. A proper switch should fully snap over to the other position when a movement threshhold is reached, and not part the gap before then.
If certain models of switches are found to frequently trip AFCIs, then those switches should be pulled from the market. I hope that testing for this is part of the UL requirement. Maybe it should be for _every_ appliance to be listed by UL, if they can establish a standard base for arc detection (as opposed to merely using the existing AFCI products). At least for switches they should watch the waveform for any bounce.
| The 2008 NEC Section 210.12(B) does not define combination-type afcis, | but requires that listed combination-type be installed. | Perhaps a definition should be added to Article 100.
Absolutely. That was a major error by the NEC.
I have read various online documents in the past that go both ways on the definition.
| Your statement that combination-type AFCI's are not on the market yet | is interesting. You mean to tell me that Code Making Panel 2 let a | combination-type AFCI requirement be added to the NEC when there are | no combination-type AFCI's on the market yet? Houston, we have a | problem here!
That may well be the case. Neither Square-D nor Cutler-Hammer (the catalogs I have that include breakers) list these devices as "combination" type devices. There are a couple cases where the word "combination" is used specifically to refer to it "combining" the feature of GFCI in the same unit. This may be (part of) the source of confusion.
| The series of articles in the IAEI news provides convincing evidence | that AFCI's do provide substantial protection and have detected many | problems in existing old wiring. A program to test dwelling units' | old wiring with a type of AFCI tester is warranted. However, I doubt | that consumers are willing to pay for the test and had rather take | their chances.
How much does such a test cost? What if the residents just don't have that much money? You see, safety _does_ discriminate against those in economically disadvantaged positions.
| All 3 types have max 50mA (usually 30mA) ground fault detection. This is | not detection at the 5mA level required by GFCIs.
I saw some in a Cutler-Hammer brochure or catalog that had 5ma level ground fault protection.
| "Combination AFCIs" in the 2008 NEC because the devices did not exist. | Now, even later, the devices still apparently don't exist.
Invest now in the company that makes red tags! :-)
| The fire marshals specifically: | - Brush off the lack of series arc protection in the existing AFCIs. | Presumably series arcs are much less dangerous than parallel. (I haven't | seen data that indicates most fires are caused by parallel arcs.) | - Brush off nuisance tripping - annecdoatal comments that nuisance trips | were caused by actual problems (*some* no doubt were).
Nuisance trips may be more like to cause people to replace AFCI breakers with non-AFCI breakers. With licensed electricians refusing to do such work, people who should not do this may be doing it.
| I look at adopting the 2008 NEC as - well it is not perfect, but we | should try to live with it and help support the many people that make | it possible. They try very hard and work very hard to produce a fine | safety standard for us and I think we owe them our support. A | backlash could potentially lead to a financial crisis at the NFPA.
IMHO, an acceptable modification to the 2008 NEC in the area of AFCIs is to allow case-by-case exemptions when a specific cause of false tripping is found and is not practical to replace. An example of something that is practical to replace is a light switch that does not part the gap fast enough to avoid some arcing time. What is practical to replace might be in dispute, and can vary based on the economic status of the homeowner. When an exemption is granted, it should be documented and a copy sent to whatever entities should have an interest (state inspection boards, NFPA, the AFCI manufacturer, the appliance manufacturer, etc). Where practical, an added dedicated circuit is another alternative.
Reduction of the use of incandescent bulbs for environmental reasons should also reduce nuisance trips that may result from them burning out. I don't know what might be needed for motorized appliances that have an issue.
In alt.engineering.electrical snipped-for-privacy@aol.com wrote: | On Thu, 11 Oct 2007 00:53:36 -0000, Gerald Newton | wrote: | |>s this going to part of the listing |>requirement for new products or does anyone have a handle on this at |>all? It looks like a bucket of worms to me. I just talked to an |>electrician in Hawaii that told me that some types of computer |>monitors are tripping afci's. | | I would expect this uis really a ground fault problem. I know my TV | trips a GFCI when it is connected to my PC and it has a 2 wire plug. I | looked and there is no voltage on the A/V ports but I bet they are | coupled to the neutral somehow. I suspect they are creating a current | carrying ground path with the PC that bonds the DC ground to the EGC.
Connect the A/V ports directly to a ground line (after testing to be sure you aren't seeing a voltage level that would give you a big blue flash).
I kinda doubt your case has this, but one cause of some false GFCI trips (and potentially false AFCI trips) is common mode RF propogating back on the power cord.
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