Electrical distributors enjoy reading about changes in the National Electrical Code (NEC) about as much as the latest Internal Revenue Service income tax revisions.

Yet buried in "Article 210-Branch Circuits" is an obscure nugget of information that will eventually add another family of products to the shelves of the average electrical distributor's warehouse. Article 210-12 alerts all in the electrical industry that three years from now, arc fault circuit interrupters (AFCIs) will be required in "dwelling unit bedroom circuits." Industry experts agree AFCIs will eventually be required for all residential circuits in new construction and will offer serious sales opportunities in the retrofitting of older residential electrical systems.

First developed to protect areas surrounding downed utility lines, the AFCIs now on the market are circuit breakers with electronic tripping mechanisms that sense low-level arcs caused by frayed appliance extension cords, pierced insulation on electrical cable, overheated wires or cords or decaying or worn-out insulation. Conventional circuit breakers, or ground-fault circuit interrupters (GFCIs), do not detect these low-energy arcs, which cause many of the 40,000 electrical fires that occur annually in homes, according to the National Fire Protection Association (NFPA) Quincy, Mass. Many of these electrical fires start in the bedroom, and that's why the first NEC requirements for these devices call for protection of these areas.

AFCIs will eventually present a market opportunity of truly monstrous proportions. Let's do the math. The NEC will some day call for AFCI protection for all circuits in a residence, and an average-sized house, townhouse or other dwelling unit can easily have 12 to 16 branch circuits. Multiply that number of circuit breakers by the annual single-family and multi-family housing starts in even an average building year, and you are talking about market demand for many millions of these devices. Now factor in upgrades of the electrical systems in the millions of existing houses and other dwelling units in the aging housing stock built in the post-War building boom of the 1950s-1960s. One of the reasons electrical inspectors, fire marshals and fire departments will support the use of AFCIs is the amount of damage these devices can prevent in older homes. Many of the house fires take place in older homes because of deteriorating wire and cable insulation in 30- to 40-year-old wiring systems.

Seldom does a new technology come along that's such a sure bet to slowly but surely transform the basic power system for residential applications. But don't load up your warehouse with these devices just yet. Some significant technical wrinkles still have to be smoothed out in the regulations governing the design and installation of these devices. Until third-party testing agencies such as Underwriters Laboratories, Inc., Northbrook, Ill., can give more explicit parameters on the operating characteristics that AFCIs must possess and the NEC committee can pass workable regulations on their application, this market will not fulfill its potential, say several industry observers.

The only currently available products using AFCI technology are circuit breakers made by Cutler-Hammer, Pittsburgh, Pa.; General Electric Distribution and Control, Plainville, Conn.; and Square D Co., Palatine, Ill. However, the still-developing UL standard that governs the design of these devices also currently allows for AFCI receptacles, a portable AFCI device that protects cord sets and portable cords with AFCI protection.

A technical bugaboo with devices other than AFCI breakers is that they are designed primarily to deter arc faults that occur in portable cords and extension cords and do not protect the wiring in the wall, an area of particular concern in older homes that could have deteriorating wire insulation.

Industry observers have some technical concerns with the current state of AFCI circuit breaker technology. Since AFCI breakers are calibrated to sense low-level arcs, nuisance tripping is more of a concern than it is with conventional breakers. Another concern is that AFCI breakers do not yet work flawlessly on circuits required to have GFCIs, such as kitchens, baths and basements, because they are currently incompatible with these devices. However, one manufacturer says distributors can expect a combination AFCI/GFCI device in the next generation of products that would provide the proper protection.

The whole issue of the relationship between AFCIs and GFCIs is an interesting one to ponder. Ground-fault circuit protection, which with every cycle of the NEC is required in more residential applications, protects potentially wet or damp residential locations such as bathrooms, kitchens, and basements, against faults to ground. In contrast, AFCIs protect against faults that occur line-to-line or line to neutral. The main intention of GFCIs in residential applications is to provide protection from the receptacle out to the load; they aren't intended to protect a building's wiring system.

Because of this focus, residential GFCI protection evolved toward GFCI receptacles, and GFCI breakers are in the minority in residential applications, says John Thomas, manager of residential marketing, Square D, Lexington, Ky. He doesn't see AFCI receptacles ever being as popular as AFCI breakers because the breakers protect the entire circuit from the load center out on through to the electrical loads, while the receptacles are intended primarily to protect equipment plugged into receptacles, not necessarily the building wiring.

A current concern is the high cost of these devices. Thomas says AFCIs can cost $60 each retail, as opposed to $6 for conventional breakers. AFCIs are expensive because there isn't the volume of demand necessary to drive down per-unit manufacturing costs. "What we are struggling with now is that there is no market for this and our volume, in terms of manufacturing, is pretty low," he says. "As we get into the Code requirement we will see volume pick up. As volume picks up, the price will come down."

Until the NEC requires them, electrical distributors should not anticipate a lot of demand, agrees Gary Forcey, commercial marketing manager, residential products, Cutler-Hammer,Pittsburgh, Pa. He says at this point in the development of AFCIs, it's a good time for electrical distributors to familiarize themselves with these devices and prepare themselves to answer any questions that electrical contractors may have on these products.

"The technology is rather exciting," says Forcey. "It's miniaturized, the same size as any other breaker, and it has these unique characteristics that sense low-level arcing faults. That needs to be communicated clearly through the distributor to the contractor. Our plan is to do that with application guides and troubleshooting guides that we would offer to distributors in the event of a query. He may have the role of educator here."

Forcey says electrical inspectors, fire marshals and fire departments will be driving factors in enforcing the installation of AFCIs. Square D's Thomas says builders are interested in the marketing potential of these products. Square D was promoting its line of AFCIs at the recent National Association of Home Builders (NAHB) show, and Thomas says builders of custom and upscale homes were interested in the products as upgrades or add-ons that could be used as marketing tools to differentiate their houses from those in other developments. Thomas also believes the time is right for distributors to familiarize themselves with AFCIs and to be ready to answer customers' questions on these products.

"From a distributor's standpoint, it's a matter of being there for contractors who have questions and making sure they are in position to help supply the demand. Initially, they will see more questions, and they should be knowledgeable on the front-end if they want to be seen as the distributor who is the leader in introducing the technology. Distributors should also take a proactive approach in creating awareness of the technology by keeping it out in the aisle, out in front of contractors."

As with the birth of many new technologies, the development of the related product listing for arc-fault circuit interruptors by third-party testing agencies such as Underwriters Laboratories, Inc., Northbrook, Ill., and the NEC regulation governing their application in the field have not been without spirited debates over exactly what these products are supposed to do and how they are supposed to do it.

One current point of contention for several experts on the subject is U.L. Standard 1699, which manufacturers will adhere to in the design of these products. These experts believe the still-developing standard is confusing because it says the devices should provide "limited protection...to branch-circuit extension wiring," but does not yet define exactly what limited protection involves. "If the NEC panel had been told when they made their decision that branch-circuit AFCIs provide undefined limited protection of cords and cord sets, they wouldn't have put anything in," says one source close to the controversy.

The current NEC regulation concerning the application of AFCIs in the field is caught in a crossfire of discontent, too. At the time it was being written, there was no product on the market, so the Code panel set a 2002 enforcement date to give manufacturers more time for research and development, and the third-party testing agencies more time to develop workable standards.

The unusual twist with this 2002 deadline is that it falls a year after the next edition of the NEC (the 2001 National Electrical Code), takes effect. Fred Hartwell, EC&M magazine's NEC expert, commends the panel for developing this requirement because it gives interested parties the time to come up with a consensus. However, he says the 2001 NEC requirements regarding AFCIs may be entirely different from those in the 1999 NEC.

While a little dynamic tension in the code-making process between parties with different agendas has been part of the development of many NEC requirements, one source who requested anonymity says all interested parties should now take the time to reevaluate the AFCI technology and how it can be applied tocorrect the core problem at hand-snuffing out arc faults in homes.

"We have not defined the problem and we have not stepped back and taken a look at all of the potential and conceivable methods of mitigating that," he says. "We are being single-product technology driven, rather than problem-driven. My suggestions to the NEC panel are to hold everything on the docket, set up a task force to look at the entire problem and all of the potential solutions and decide how to go from there.

"There are all of these issues out there, and unfortunately what happens under these circumstances is that someone develops a technology, and they take it as a solution to a problem. You get this railroad train going down the track and nobody is stepping back and taking a look at the bigger picture. If I were writing an article for distributors today on AFCIs, I would say it is a work in progress, and nobody knows where it is going to end up.