Fires in residential structures, which include one- and two-family dwellings, apartments, hotels, and college dormitories, accounted for approximately 84% of fire-related deaths and 81% of fire-related injuries in 2008, according to the U.S. Fire Administration. In an ongoing effort to help lower these statistics, Alpharetta, Ga.-based Siemens Industry, Inc. recently introduced a 2-pole combination-type arc fault circuit interrupter (CAFCI) that not only enables end-users to isolate the type of problems that may cause a device to trip, but also reduces wiring costs as well as installation and troubleshooting time.

Currently the only product of its kind on the market, the device assists users in distinguishing between line-to-neutral arcs, line-to-ground arcs, and series arcs via LED indicators that appear for 5 sec each time the AFCI is turned on up to 30 days after the last trip.

“LEDs located near the breaker's handle define what type of arc fault condition is occurring,” explains Josh Angel, Siemens' distributor sales engineer. “One LED lights up if the last trip occurred because of an arcing fault. The leg that the arcing fault was detected on can be confirmed based on which single LED was illuminated. No indication is displayed if the AFCI trips due to an overcurrent condition.”

In addition, the last known trip indication can be cleared from memory to aid in verifying resolution of the problem by following a few simple steps. According to Greg Robles, vice president of Vertical Electrical, Inc. in Greenwood Village, Colo., the product's LED indicators are one of the main reasons he recommends the device to others.

“They not only increase the safety of residential structures, but also reduce the time it takes to troubleshoot a problem,” he says.

Another advantage offered by Siemens' 2-pole CAFCI is the product's ability to accommodate multi-wire branch circuits, also known as shared neutrals, which the company says reduces wiring costs and installation time.

“Single-pole CAFCIs require a dedicated neutral for each circuit,” notes Angel. “But our device allows electricians to use 14/3 wire and 12/3 wire.”

Robles says this capacity to share neutrals between the two circuits fed by the breaker comes in handy when installing long cable runs.

“Any time we are able to use 14/3 or 12/3 wire, it saves us on cost because less copper equals less money spent,” remarks Robles. “Also, the amount of installation time is reduced because we have to pull less wire. Who doesn't want to save time and money?” According to Siemens, the 2-pole CAFCIs meet all requirements of the current and proposed NEC. UL-listed, they are available for use on 120V single-phase, 15A and 20A circuits. In addition, the product is UL-listed for retrofit applications for all Siemens, Murray, I-T-E, and Crouse-Hinds load centers and meter/load center combinations.

Although pricing for the 2-pole CAFCI varies slightly throughout the country, Angel says the product typically costs double that of a single-pole version.

For more information on Siemens' combination-type arc fault circuit interrupters for residential applications, visit www.usa.siemens.com/afci.