Code Making Panel-2 (CMP-2) recognized the need for arc fault circuit interrupter (AFCI) protection when it accepted proposals and accompanying substantiation for the 1999 National Electrical Code (NEC). Now, as the January 1, 2002, implementation of AFCI requirements in Section 210-12 of the 1999 NEC rapidly approaches, AFCI technology is progressing rapidly. CMP-2 anticipated that progress, recognizing that a delay would spur AFCI development and completion of an AFCI product standard (UL 1699).
CMP-2 correctly anticipated that acceptance of the AFCI proposals with a delayed effective date would further stimulate technological innovation and push the completion of a viable product standard, UL 1699, covering AFCIs. This not only happened; in fact, AFCI technology has progressed so much that new products are being introduced that will expand UL 1699 and provide alternate ways of complying with the NEC requirements, providing additional safety and convenience for the installer and end user of the AFCI device.
The need for AFCI protection has beenclearly illustrated, most effectively through Consumer Product Safety Commission (CPSC) data. Residential electrical equipment is involved in approximately 41,000 fires each year, resulting in more than $700 million in annual property losses. The cost of this technology can be justified in property loss alone; however, the 360 deaths and thousands of injuries resulting from fires undeniably close the case for AFCI protection!
A complete understanding and definition of arcing and its prevalence in the residential wiring system are important when searching for a solution to the arcing problem. Arcing is defined as a luminous discharge of electricity across an insulating medium. An arc can cause a fire once the electrical energy from the arc is converted to thermal energy and the heat generated is transferred to a combustible material that ignites.
Arcing can occur in wiring in two basic forms: parallel arcing and series arcing. Both of these arcs are capable of starting fires at very low levels of current.
Parallel arcing is an arc fault between two conductors, hot and neutral or hot and ground. Examples of parallel arcing include a metal object penetrating the insulation of a cable or a cord “shorting” the hot wire to the neutral or equipment grounding wire.
Series arcing occurs on a single conductor when a break in the conductor occurs and an arc is established between the broken ends of the conductor. Examples of a series arc include loose terminations in a twist-on wire connector and at device terminations, as well as a partially severed piece of lamp cord, a poorly wired fixture, or even a loose termination in the service panel.
Currently the UL standard recognizes five different types of AFCI products: branch feeder, outlet, combination, portable, and cord. By UL standard definition, only the branch feeder AFCI would satisfy the requirements of Section 210-12 of the 1999 NEC.
The latest technology, when incorporated in a receptacle and installed at the first outlet, protects the branch circuit from the overcurrent device to the outlet, the branch wiring downstream, plus cords and extension wiring, complying with UL 1699 for both branch feeder and outlet-type requirements.
The new outlet branch circuit devices are compliant with NEC 210-12 requirements, as they protect the branch wiring as defined by UL. An AFCI in a receptacle embodiment provides additional solutions and methods of application that prove favorable to the electrical contractor and the homeowner when complying with the NEC.
Outlet branch circuit devices also show great promise for old-work situations with two-wire systems, as no ground wire is required, providing protection from arcing when installed in older homes. This technology is currently being tested in a wide variety of applications and geographic locations, ensuring that the final product meets electrical contractors’ demands, eliminating callbacks, easing installation, and providing unquestioned quality.
Based on the proactive approach, both UL and CMP-2 took in attacking the arcing problem, advancements in technology will surely be endorsed and encouraged. Ultimately, the professional electrical contractor and the consumer will decide the AFCI protection level, embodiment type, and AFCI product installation location. The NEC and UL must make every effort to continue supporting the advancement and inclusion of emerging technology, amending and updating both UL 1699 and the NEC requirements to accommodate the alternative products that address these needs. This support will enable electrical contractors to provide the maximum level of practical arc fault protection while complying with the NEC and satisfying the needs of their customers.
McMANUS is residential product manager for Pass & Seymour/Legrand. He can be contacted at (315) 468-8281 or via e-mail at email@example.com.