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Where can I get info. on these devices? What exactly do they do, protect against? Are they installed in place of a standard curcuit breaker?
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Search here using "arc fault".
*I got mine yesterday at Home Depot for a general electric box, $32.00 each.
*I haven't got the new NEC code book yet, but it is my understanding that use them instead of the GFCI breakers and recepticals. Wherever you would normaly place a ground fault circuite or device, you now use a arc fault breaker for the protection of the whole circuit.Maybe Gunner or IBEW Barry will answer with more/better information.
*Arc fault detectors DO NOT REPLACE OR SUBSTITUTE FOR GFCI.They detect intermitant connection in circuits, ie arcing. The 99 NEC called them out for use in bedrooms, I think starting Jan 2002, but don't have the reference.In the last couple of months the "up front" sections of one of the mag's, I think JLC, but not sure. Any way it said that some of the AHJ was holding back on requiring the arc detectors until there is more experience in the field. It also implied that there was not a clear spec what what arc's that where detected. Basically what the arc detected was the type of arc that the units detected.They sense rapid increase and decreases in curent that would be caused by problem with loose connection in a heating device or extension cord feeding the heating device (decrease in current). Or a short in an extension cord as it has been overload and started to melt (increase in current).They are spec for bedrooms as they are the location where there are a good chance for heating equipment that degrades the insulation and the ocupents are asleep and not notice the problems.
*Would they protect a child from getting electrocuted if he/she stuck something in a receptacle or bit a lamp cord?
*AFCI's do not protect from electrical shocks. The idea is that they recognize the current wave forms of electrical arcs, and will prevent fires. As they are a new product, the NEC is going slow on requirements for them. The idea of only requiring them for bedroom outlets is to gain a performance track record. In other words, it's still in the experimental stage, and builders today are "beta testing" these devices. The breakers look almost identical to a GFCI breaker, and they have a pigtail to the neutral bus. Cutler Hammer makes an AFCI that is also a GFCI. Even a GFCI will not protect a child from electrocution if they stick a paper clip in each side of a receptacle. Douglas HansenCode Check
*For a good explaination of AFCI's see the link below:http://www.ul.com/regulators/afci/index.html
*AFCI's protect against high-impedance faults that have insufficient energy to trip a conventional magnetic/thermal breaker, but enough energy to start a fire. Most fires are caused not by "hard faults," which is essentially a short-circuit, but rather arcing faults that persist for long periods of time. Loose joints, nicked conductors, roto-zipped wires in boxes, etc. can all lead to high-impedance faults.They do not offer shock protection!James Cross
*Seems like the regulators don't have enough to keep them busy. Now, before you pass me off as a raving nut - I grew up in the explosives industry, and know the criticality of safety in electrical service.I also have a more extensive background in research on arcs, their creation and sustainment than the average bear. That being said, let me comment.Yes, arcs are a problem. But, are we ready to protect against them w/ current technology? I don't think so. IMVHO, the technology is not mature enough to gain long term acceptance by the sleeping public. Maybe the BR is the best place to start, since all the folks are mostly senseless, (asleep)and there are probably fewer devices that can cause arcs as a part of their normal operations to spoof the breakers. But - if these devices are poorly reliable and have a terrible false alarm rate, they will be replaced w/ normal breakers by DIY owners. It will not take a very high false alarm rate to make them unacceptable. Every switch will have a small arc when breaking - get a breaker that trips too often on that, and the owner/electrician system will go nuts. Given the legal liability situation the electrician faces, he/she must err on the side of safety. Try finding the offending switch! Is it really an arc or an overly sensitive breaker? Will these things go the way of pennies under a fuse? I have no real love for Service panel GFCI's, and have heard more than one electrician express the same love/hate relationship w/ them. Will AFCI's go the same route? I am building right now, and just finishing the wiring. I just bought my allocation of $40 Siemens AFCI's. I've had two electricians express displeasure w/ the concept. GFCI's have won social acceptance. HD keeps themunder lock and key even though they cost less than AFCI's. This means people will stel GFCI's, but not AFCI's. To me the jury is out. I liked the comment about beta testing. Swell! I read all the verbiage in the link about them. Does anyone here REALLY believe that they will be tested monthly? REALLY???? Are GFCI's tested monthly in the real world? H*** no!!! I test every GFCI in hotel bathrooms w/ a hair dryer. I hit the test button and plug in the dryer. In 10% of the cases the dryer operates. A rather crappy track record. Do eyewash stations in industrial facilities get tested as often as they should? NO. I know because I've inspected the inspectors for it. These things will be buried in the service panel, deep in a basement or utility room. Out of sight, out of mind. A setup for failure from the user angle. Good thing the CPSC wasn't around for Faraday and his cohorts - we'd still be using candles. It's too soon, and we are trying to do too much w/ one device. We can already protect against arcs in many environments inb the house wiring system - use explosive safety standard electrical systems. Expensive as all getout - that's why it isn't used in residential situations. If we want these devices to work and be accepted, they better be darned good and reliable w/nearly a zero false alarm rate. Many great ideas have been scuttled for all these reasons.Don Reinhard, Curmudgeon First Class
*Rich,We're all just learning how they're going to work out,as they are a brand new requirement for bedroom circuits in the 2002 NEC.They address two electrical problems that start a great number of electrical fires: Pinched electrical/extension cords and worn out receptacle/loose, sloppy attachment cap connections.When electricity flows through a good conductor,such as copper,little heat is produced,but when electricity is forced to flow through a poor conductor,in this case air,a considerable amout of heat can occur.As others have said these faults usually don't draw enough current to trip a circuit breaker,but they generate more and more heat over time.If AFCI's work they will stop an awful lot of fires from starting.
*I think the wording in the Code requires AFCIs for 125 volt bedroom receptacles. If you install 120 volt receptacles, you slip under the requirement [aka "loophole"]. After five years in the business, I have not yet seen one. I think there is some shenadigans going on here. Some lobbyist probably took the right Code-making-panel-members out to a very expesive lunch. It's a great marketing tactic to get your untried product required by some Code. Compare this with the history of seat belts. At first, they appeared only in luxury cars and maybe Volvos. And only for the driver. But then the statistics started showing that they did save lives. It went on from there so now we have shoulder straps, air bags, buckle-up laws and so on. But the principle is that they should be field proven first. -Peter
*Peter,You're joking about 120 volt receptacles being a loophole, aren't you?Barry
*Don:"I have no real love for Service panel GFCI's, and have heard more than one electrician express the same love/hate relationship w/ them"How come? What os the problem you see with them?
*Ptere:"Compare this with the history of seat belts. At first, they appeared only in luxury cars and maybe Volvos"First seat belts I ever saw (and I worked in a service station so saw a lot of cars) were in my 1965 Valiant convertible. That weren't no luxury car (although that old Slant 6 225 cu in was one of the best engines ever made!)
*I think that Ford started pushing seat belts back in the late 50's and ended up withdrawing them (or putting them on the back burner) as it was hurting sales.
*I really do not see what the problem is. If they work! I did not think $35 was bad since they replace the breaker. I know they are more money but piece of mind to me is worth the money. Beside if its not here the money would be spend on something else. All the electrian here in town think the world coming to an end due to these.
*Bob Walker: In panel GFCI's: Unhappiness over their reliability and longevity. I have likewise seen it. Really prefer the GFCI located at the outlet. Not the concept or requirement - it is widely accepted - just the in panel devices.Peter: My first seat belts were in a 1960 Studebaker Lark station wagon. Self installed in Dec 1960. About 4 ft long, and a pain in the tush to fasten & unfasten because of the long tail you had to pull through. That pain caused their acceptance by the geneal public to be delayed. Even w/ the convenience of the snap buckle, you still have less than 90% usage in many places, and they are not even REQUIRED in pickin'uptrucks in GA. Interestingly, one of my father's cousins invented the snap buckle in use today, according to family lore. He was working for Lockheed at the time.$39 is a lot of money to pay for a device that becomes a PITA. A standard breaker only costs about $5.Also, if you read all the poop in the original link, you find that the Code requirement does not completely protect you against arcs in the most dangerous location - extension cords or device cords. As one comment said - a chair leg on a cord, or metal frame cutting into it. Guess what! That sort of short is reasonably well protected against for our in wall wiring, and that is where the AFCI in a panel protects you. The closer you get to the load (Like the lamp cord on the floor) the poorer the reliability.Don
*IBEW Barry, There was a thread on this in the Mike Holt forum.To the other replies, I was just citing the seat belt introduction as an example. At the time, I was too young to drive so I didn't pay that much attention. But my point remains. I would rather have AFCIs tested in the field before they get required by law [Code}. -Peter
*PM: I agree; there is a big "HOWEVER" to this. You can test till you are graybearded and not come up w/ all the possible things that can go wrong.When you are talking a safety device, it has to be thoroughly field tested or it will never gain public aceptance. And, it also has to be tested against reasonable criteria. As I read the many types of faults you have to face, the panel breaker is not all that good against some arc faults. Better not sell it to the public, that is not really up to understanding all the nuances, and face potential liability issues. Look at what we face now - many devices have integral GFCI's in their plugs. String too many safety devices in series and you set up for failure due to them.Don
*Hey Peter,I searched the Mike Holt site(a great one BTW) and I'm not sure which thread you're refering to.The Code always refers to receptacles as 125 volt rated and I've never seen anything else....
*210.6 Limits voltage to 120 volts, in a dwelling. IBEW Barry,"There can not be any 125 volt branch circuits.AFCI's are required only on 125 volt systems.Therefore they are not required.The words of the text, do not provide legal substantiation for enforcement."I just did a quick check of the Mike Holt forum. I used the search function and one of the items had something to do with "125 volts" in the title of the thread. Anyway, the above quote is what I was refering to. I think it was Bennie Palmer who came up with this. -Peter
*"terrible false alarm rate"I recall certain functions of the "intelligent" circuit interupters on the space station were disabled due to false alarm rates Nothing replaces good old maintenance for safety but 95% of homeowners (maybe 99.9%?) never check any system prior to failure. There are predictions that by 2020 house wiring will be UNGROUNDED (much safer IF a method of detecting that one side gets grounded thru a fault) when AFCI and GFI are fully mature. Worked with an Eng. in early 80's who was on an NEC panel/committee. The committees that come up with the new stuff for the code have heavy representation of equipment manufacturers, e.g. "internal" lobbyists
*PeterYou left out one important word, NOMINAL.210-6(a) "..the voltage shall not exceed 120 volts, nominal, between conductors..."And section 100- Voltage, Nominal makes it clear that this is not a voltage limit, but a way differentiate between classes (240, 480, etc). And calls out ANSI C84.1 - 1995 for details.I have not seen the actual C84.1, but it seems to suggest a long term range of 116 to 126 volts.But it is interesting that the NEC calls this 120 volt service, but the outlets are called 125 volts, and motors that are rated at 115 volts, but many people call it 110.PS, I could not find it this time, but I found a reference a few weeks ago that in California they reduced the upper range of nominal a couple of volts to reduce power usage.
*Don,Interesting: "Bob Walker: In panel GFCI's: Unhappiness over their reliability and longevity. I have likewise seen it. Really prefer the GFCI located at the outlet. Not the concept or requirement - it is widely accepted - just the in panel devices."FWIW, as a home inspector, I don't think I've run across any in panel GFI breakers which had failed; ummm, maybe one. I run across plenty of receptacle GFI's which have failed, but, of course, I see far more GFI receptacles than breakers. (I also run across plenty which have been miswired!)During an inspection, if I run across a GFI breaker, I test it by pressing the test button (but have always wondered what exactly that tests?) I also use a GFI receptacle tester, and should catch 'em that way, as well, when the circuit has receptacles on it.Most of the GFI CBs I see are for whirlpool and hot tubs, however, so they only get tested with the breaker test button.Just to be clear, I'm not trying to argue, I don't have enough expereince with the CBs to base an argument on; I'm
*BobWhat the test button is suppose to do is to connect a test resistor across the line and neutral. But one connection is after the current sense coil and the other before the current sense coil. This simulates what happend when you have an external fault. It is a very good test of the GFCI logic.But it does not show if the outlet was miswired. At least on company makes a GFCI outlet that has addtional features to detect if the outlet was miswired.BTW, when my house was built in 1979 they ran one line to 3 baths and then a couple of outside outlets. I understand that was not uncommon during that time. The idea was to allow one GFCI breaker to be used for all outlets. But the GFCI was never installed, or pulled after the inspection.
*Just to play devil's advocate...If there are say three bedroom circuits in a "modern" (read large) house that will need these breakers, it will add about $100 to the materials cost.Instead of the special breakers, what if used half that money to spend an extra hour making sure all wire nuts are tight, zip ties aren't pulling things the wrong way, etc, and use the other half to upgrade to industrial/hospital grade receptacles (instead of the grab bag of quick-wire cheapos)?Not that I follow conspiracy theories that corporations might lobby for "safety" changes that provide them financial gain (like inane requirements for EV charging stations), but...
*Jim...i Instead of the special breakers, what if used half that money to spend an extra hour making sure all wire nuts are tight, zip ties aren't pulling things the wrong way, etc, and use the other half to upgrade to industrial/hospital grade receptacles (instead of the grab bag of quick-wire cheapos)? Good idea... but the real world is just not there. So I think these new breakers are a great idea.near the stream with old cords and outlets,ajps... I do residential electric contracting besides Tennis courts and home building.
*Bob Walker: These aren't arguments, but great discussion. I have run into three bad CB GFCI's and at least one bac outlet GFCI. I am just a home owner, and the bad stuff was in my house and houses belonging to a daughter and a son. In three states - GA, NC, IL. We all generate conclusions based on the data we see, and compared to the nation as a whole, it isn't a large sample.Don
*I need a "My Fault Interrupter" seems like when something goes wrong here it's always my fault, maybe there is a gadget out there that could kick me in the butt and wake me up before I make a major mistake.