Story ID: 
Improved circuit breakers in flight test
By: Kim Rosenlof
Caption: Irvine, Calif.-based Eaton Corp.
Word Count: 190
Irvine, Calif.-based Eaton Corp. (Booth No. 5967) recently celebrated the successful flight testing of its arc fault circuit breaker (AFCB) technology as a stand-alone replacement for existing circuit breakers. Completing more than 350 normal service flights aboard a U.S. Navy DC-9 and the FAA Research Center’s B-727, the Eaton AFCBs accumulated more than 5,000 hr of operation in multiple circuits ranging from fuel boost pumps to position lighting. Because AFCB units can detect wire arcing in a typical aircraft 115-volt, 400-Hz electrical system, this presents a critical improvement in circuit breaker technology since the FAA and NTSB have cited electrical system arcing as one likely cause of the cabin fire and crash of Swissair Flight 111 and the explosion and crash of TWA Flight 800. According to Eaton sources, arcing conditions resulting from damaged or old wiring insulation can reach temperatures of more than 6,000 deg. The AFCBs use integrated electronics to diagnose when arcs or intermittent short-circuiting occurs in the wiring, then immediately isolates the circuit from the rest of the system.Eaton AFCBs can be installed as direct replacements to existing circuit breakers with no additional connections, wiring or site preparation.