Arc Fault breakers

How do the new arc fault circuit breakers work? What characteristic of a
fault do they detect, and do they do that with clever electronics or some
analog means? I see that you have to connect the circuit's neutral to
them and connect a neutral pigtail to the neutral bus, like a GFCI
breaker. Do arc fault breakers also work as GFCI breakers (either de
facto or legally)? By legally I mean does the code allow an arc fault
breaker in a location where it requires a GFCI breaker.
Reply to
Michael Moroney
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Arc fault interrupters look at the signature of an arc based on current. They do incorporate ground fault protection but at a higher current level than is required for a GFCI (~30ma vs ~ 5 ma) so they are not interchangable. I think there is still an article on the Cutler Hammer web site on AFCIs. They were one of the primary inventors.
Reply to
Greg
| Arc fault interrupters look at the signature of an arc based on current. They | do incorporate ground fault protection but at a higher current level than is | required for a GFCI (~30ma vs ~ 5 ma) so they are not interchangable. | I think there is still an article on the Cutler Hammer web site on AFCIs. They | were one of the primary inventors.
AFCI is required in a bedroom. GFCI is required in a bathroom. If you have a bathroom in a bedroom, and you don't want those PoS ugly GFCI receptacles (why won't they make some nice ones?), which type of breaker would you use?
It's only gonna get worse unless the NEC starts requiring that the only devices that meet code are those made by manufacturers which will make a complete selection of such devices and put them all in their distribution channels. This includes 2 pole and 3 pole AFCI devices, including versions with people protection level (2 to 6 ma) GFCI integrated. Cutler-Hammer is definitely a step ahead of Square-D in this regard.
Reply to
phil-news-nospam
A bedroom is a bedroom, a bathroom is a bathroom. AFCI in the bedroom, GFCI in the bathroom and you can use the GFCI breaker if the looks of the receptacle bother you. A combo device won't do anything for you in this situation since bathroom circuits can have no other outlets so the bedroom has to be on another circuit anyway.
The ONLY requirement for AFCI is 15 and 20a single phase 120v circuits in bedrooms. Why would I need a 2 pole or 3 pole?
Reply to
Greg
|> If you have |>a bathroom in a bedroom, and you don't want those PoS ugly GFCI receptacles |>(why won't they make some nice ones?), which type of breaker would you use? | | A bedroom is a bedroom, a bathroom is a bathroom. AFCI in the bedroom, GFCI in | the bathroom and you can use the GFCI breaker if the looks of the receptacle | bother you.
When the bathroom is in the bedroom, especially the open vanity type which either open directly to the bedroom or are integrated into a walk in closet, have been treated by inspectors as part of the bedroom, just as they treat a regular closet.
Would your inspector let you install a NON-AFCI outlet in a bedroom closet?
| A combo device won't do anything for you in this situation since bathroom | circuits can have no other outlets so the bedroom has to be on another circuit | anyway.
The point being that the bathroom falls under the bedroom AFCI requirement. An open vanity definitely requires a GFCI on receptacles within 6 feet (if I recall the correct distance).
|> This includes 2 pole and 3 pole AFCI devices, | | The ONLY requirement for AFCI is 15 and 20a single phase 120v circuits in | bedrooms. Why would I need a 2 pole or 3 pole?
For all new construction today, you don't. To add more outlets to existing wiring does fall under the new rules and requires an AFCI breaker replace the existing one. But, much existing wiring is of the shared neutral type. While not advisable, separate breakers for shared neutral work, and have been considered compliant with code (which apparently only requires a common handle for shared neutral within the same device/yoke). But in such cases, separate single pole AFCI (or GFCI) breakers do not work. This will be obvious when you try to wire them up, as you end up with two different places to attach the one neutral (it won't work to bridge them together). GFCI is available in 2 pole, so shared neutral in the kitchen (also common, and even common on the same device) can be dealt with.
Efforts are already underway by many parties to push for wider requirements for AFCI. And on a fundamental basis, I support such a requirement. What I think is a travesty is that what is obvious to many as a definite safety device just isn't manufactured in ways that allow it to be properly used in all the circumstances that could benefit from it (almost the entire home, for example). This hasn't been added to NEC 2005 as of the last draft I saw, so I doubt it will be there. But maybe in NEC 2008 you'll have to use AFCI in more locations, possibly for all non-dedicated circuits. I'd push for it in all "convenience" receptacles at a minimum.
Reply to
phil-news-nospam
requirement.
requirements
Though I agree with you in principal; though it is very sad in my mind that the industry must continue to create a better "mouse traps" because the public is getting less intelligent. There was once an fireman that ran an extension cord across his daughters bed for an electric space heater. When the fire erupted, he was hailed as an hero because he had an smoke detector in her bedroom on the local news. I was appalled, and called the information officer for the fire department (old friend) and questioned him. The story was pulled and the fireman was demoted and sent back to electrical safety training again. I know all of the major manufactures have delegates that sit on the NEC and NFPA boards. So when the rule committees are leaning toward something the manufactures can be ready for the requirement.
Reply to
SQLit
A closet is a closet, not a bedroom. They just had this discussion on the IAEA BB.
That is an interesting question, I will kick the boys at IAEI with it. I would say you GFCI the countertop receptacals and AFCI the rest.
BTW there is no rule about GFCIs around ANY sink, only sinks at wet bars (new 2002). The GFCI in kitchens is any receptacle serving any countertop and the bathroom needs them on all receptacles. You could code argue that the vanity sink in a bedroom is not a bathroom since the toilet, tub and shower are not in that room but I agree with you GFCI should be there. There is nothing to keep you from putting a GFCI receptacle on an AFCI breaker and that is what I would say they need.
If you have a multiwire circuit you will be rewiring that if your remodel includes rewiring the bedroom. If this becomes a big enough problem I am sure they will come out with a 2 pole AFCI. The 2005 code is out, I have had mine for over a month. They did change the AFCI rules so you can remote mount a device next to the panel so you could have a Cutler Hammer breaker in a small panel on a Square D service. It can also be a receptacle. They did not expand the requirements
Reply to
Greg
It is even a closer relationship than that. Two of the three proposals for AFCI in the ROP to the 99 code were Cutler Hammer and Square D reps. EIA being the 3d. They invent something and then get it incorporated into the code.
Reply to
Greg
| Though I agree with you in principal; though it is very sad in my mind that | the industry must continue to create a better "mouse traps" because the | public is getting less intelligent. | There was once an fireman that ran an extension cord across his daughters | bed for an electric space heater. When the fire erupted, he was hailed as an | hero because he had an smoke detector in her bedroom on the local news. I | was appalled, and called the information officer for the fire department | (old friend) and questioned him. The story was pulled and the fireman was | demoted and sent back to electrical safety training again.
He must have slept through the first class.
| I know all of the major manufactures have delegates that sit on the NEC and | NFPA boards. So when the rule committees are leaning toward something the | manufactures can be ready for the requirement.
One problem with that is people question the motivation of some of the rules as being from manufacturers trying to drive up demand.
Reply to
phil-news-nospam
|>Would your inspector let you install a NON-AFCI outlet in a bedroom closet? |> | | A closet is a closet, not a bedroom. They just had this discussion on the IAEA | BB.
So the guy who had the treadmill for exercising in his bedroom, which was always tripping his AFCI, could have an outlet installed in the closet and run an extension cord over to it, can solve his problem. I don't remember which forum that issue came up in. A lot of crazy recommendations were tossed around.
|>When the bathroom is in the bedroom, especially the open vanity type which |>either open directly to the bedroom | | That is an interesting question, I will kick the boys at IAEI with it. I would | say you GFCI the countertop receptacals and AFCI the rest.
If they made AFCI with people protection 6 ma GFCI integrated (as opposed to the equipment protection 30 ma) then having the AFCI alone would cover it.
| BTW there is no rule about GFCIs around ANY sink, only sinks at wet bars (new | 2002). The GFCI in kitchens is any receptacle serving any countertop and the | bathroom needs them on all receptacles. | You could code argue that the vanity sink in a bedroom is not a bathroom since | the toilet, tub and shower are not in that room but I agree with you GFCI | should be there. There is nothing to keep you from putting a GFCI receptacle on | an AFCI breaker and that is what I would say they need. | | If you have a multiwire circuit you will be rewiring that if your remodel | includes rewiring the bedroom. If this becomes a big enough problem I am sure | they will come out with a 2 pole AFCI. The 2005 code is out, I have had mine | for over a month. They did change the AFCI rules so you can remote mount a | device next to the panel so you could have a Cutler Hammer breaker in a small | panel on a Square D service. It can also be a receptacle. They did not expand | the requirements
Not all "rewire" is "all at once". What if they are just adding one more receptacle to an existing bedroom. We all know older construction often has too few receptacles and often poorly placed. Adding a new one a few feet away to avoid using an extension cord (something someone might do if they had a "little fire") is not all that hard to do. But rewiring to undo the shared neutral would require a full teardown in most cases. And that's a big money issue for most people (more about having it all at once rather than ever having the money at all). Shared neutral is not that much of a problem if it's all under a single breaker handle. The problem is, when someone adds a new receptacle, the AHJ may interpret that as being big enough to count as "new work" that forces it to fall under the current code and require a little more expensive of an AFCI. If they have a Cutler-Hammer panel, they are in luck because the AFCI is available. But if they have Square-D, they are out of luck (buying and installing a whole new panel is out of the question, too). If the work won't be approved by the AHJ, then it might not get done, and then a dangerous situation will remain. So for now, I do not recommend Square-D to anyone. Once they do offer a 2-pole AFCI, then my recommendation goes back to saying either one is fine.
Reply to
phil-news-nospam
... Or from the hall, living room or wherever BUT he should probably just get his treadmill fixed. It's like people who cut the ground pins off their power tools because they trip the GFCI.
I would tell them to put it on an AFCI and pick up as many existing as possible. I know what you mean tho. The 2 bedrooms on the far end of my house are on a multiwire circuit. If I ever do get around to remodelling them I will just pull two Romexes down to that ceiling box where the MW lands and split them. I really don't know why the original builder did that in the first place. He couldn't have saved any real money. 14/3 is not that much cheaper than two 14/2s. It may have been a voltage drop issue since this is the longest circuit in the house.
The 2005 code allows you to put in a remote AFCI next to the existing panel (something like 6 feet) so people don't need to replace all of those obsolete panels on a minor remodel.
You can't even get an AFCI from SqD right now. They are recalled and the replacements haven't shipped.
Reply to
Greg
| I would tell them to put it on an AFCI and pick up as many existing as | possible. I know what you mean tho. The 2 bedrooms on the far end of my house | are on a multiwire circuit. If I ever do get around to remodelling them I will | just pull two Romexes down to that ceiling box where the MW lands and split | them. I really don't know why the original builder did that in the first place. | He couldn't have saved any real money. 14/3 is not that much cheaper than two | 14/2s. It may have been a voltage drop issue since this is the longest circuit | in the house.
Then you might want to do two 12/2s just in case (and put in 20A devices and protection, too).
| The 2005 code allows you to put in a remote AFCI next to the existing panel | (something like 6 feet) so people don't need to replace all of those obsolete | panels on a minor remodel.
That was prohibited by the existing code? I'd call it a subpanel.
| You can't even get an AFCI from SqD right now. They are recalled and the | replacements haven't shipped.
That's just for the moment. But I would be curious about any stories of home inspections delayed due to this. FYI, C-H does make classified breakers for many SQ-D panels, including 1-pole AFCI (though no 2-pole). I wonder if people are using those.
Reply to
phil-news-nospam
I always run 20a #12 on new circuits, but I am not trying to make money ;-)
You can also use a receptacle type AFCI
I only know of one AHJ in SW Fla who is holding up COs. (The City of North Port) Most are giving a conditional and requiring a reinspection when the new AFCI is installed. Square D is paying for all expenses to the customer.
Reply to
Greg
| You can also use a receptacle type AFCI
I haven't seen one of those, yet. They are not in my copies of Leviton and Hubbell catalogs.
| I only know of one AHJ in SW Fla who is holding up COs. (The City of North | Port) Most are giving a conditional and requiring a reinspection when the new | AFCI is installed. Square D is paying for all expenses to the customer.
I read the Square D announcement about that. But given that, I was just wondering how well AHJ's would deal with it, especially the timing issues.
And of course in Florida there is a lot of repair work going on right now.
Reply to
phil-news-nospam
They really didn't have a good use until the NEC changed. I think they have always been in the listing standard
Reply to
Greg
Good work if you can get it.
I met the guys from CH a couple of times. I was impressed at how much common sense that they had. Not just egg-heads but down to earth and savvy on practical issues. Not like some engineers I have been associated with.
Reply to
SQLit
| You can also use a receptacle type AFCI
A lot of the literature I see from Square-D and Cutler-Hammer regarding AFCI protection includes showing in the wall wiring as being one of the hazards that can be protected. To that extent, an AFCI receptacle does not provide that protection for the upstream wiring. GFCI protects people and equipment. AFCI protects wiring (in the wall, fixtures, and connected cords). So I believe an AFCI receptacle does not meet the spirit of the protection (and therefore the code). But it could then be argued for AFCI protection on more and more wiring. And I do believe many people are doing just that (I've seen some state level proposals to go beyond NEC and require AFCI on more home and office wiring, mostly coming from fire and safety groups). I do think NEC acted wisely to do what appears to me to be a gradual phase in of AFCI so that costs are not imposed too heavily while the learning curve is in place (including learning curves like manufacuring issues such as Square-D learned the hard way recently).
Reply to
phil-news-nospam
The 2002 NEC (210.12.B) states: "All branch circuits that supply 125-volt, single-phase, 15- adn 20-ampere outlets installed in dwelling unit bedrooms shall be protected by an arc-fault circuit interrupter listed to provide protection of the entire branch circuit."
This is generally considered to include the everything in the circuit, including the wire. This pretty much means an AFCI breaker.
Greg wrote:
Reply to
Alan Stiver, PE

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