www.esterline.com/powersystems
When it comes to ground faults and fuel tanks, there are two vulnerable areas that need protection from electrical
mishaps. The first is the fuel pump’s circuitry; the second is the wiring ‘up-stream’ from the pump.
Our Ground Fault Interrupter (GFI) products protect the first area by detecting and isolating fuel pump ground faults;
while our Fault Current Detection (FCD) products protect the second by detecting fuel pump ground faults and phaseto-phase shorts in the fuel pump and down-stream wiring. Through the use of a proprietary electronic circuit design,
these GFI and FCD products trip affected circuits to open positions within 10 milliseconds, thereby minimizing the
potential of combustion inside the fuel tank.
GFI Family
AN ADVANCED SOLUTION FOR GROUND FAULTS
PROBLEM: Aircraft have become more electrically complex and as existing aircraft age, the problems with
electrical wiring and wire harnesses become more significant, particularly with respect to the possibility of electrical
ground faults. Faults of this type can result in significant damage to wiring and equipment. Electromechanical
protection devices, such as circuit breakers, are not usually capable of detecting and isolating ground faults fast
enough to minimize this damage.
CONCEPT: Our method of ground fault isolation uses a fundamentally simple and well-proven technique. The total
electrical current flowing to the load is compared with the current that returns from the load. A difference between
these two values indicates that the current is returning to the source through an unexpected path, i.e. a ground fault.
SOLUTION: To readily provide ground fault protection, we have developed ground fault sensing contactors and relays
that have the capability of detecting and isolating ground faults, giving added protection for wiring and equipment.
SIMPLIFIED RETROFITING
In June 2001 the U.S. Federal Aviation Administration (FAA) issued special federal aviation regulation SFAR-88, which
requires transport-category aircraft manufacturers to modify fuel systems to eliminate the possibility of an ignition source
developing within a fuel tank. Our ground fault isolation solutions meet the SFAR-88 requirements, and our products
are compatible with the wiring interfaces, footprints and form factors of the components that they replace. Although
no protection system is perfect, the ground fault detection technology substantially reduces the chance of electrically
induced combustion within aircraft fuel tanks.
The GFI feature has been incorporated into subminiature & balanced armature relays, as well as contactors — all work
horses extensively used in commercial and military aircraft electrical systems
To aid in troubleshooting, all Leach brand FCD and GFI components come with a built-in test feature to allow aircraft
mechanics to verify that fault sensing is functional. As well as a visual trip indicator on each device that alerts mechanics
that a ground fault has occurred.
A
B
C
}
LOAD
Test
BIT
X1
POWER
SUPPLY
FAULT CURRENT
DETECTOR
X2
System block diagram
FEATURES
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Trip indicator
KC Type with GFI
Fast trip speed
Built-in test (BIT)
Various contact ratings and configurations available
Fully qualified, drop-in replacement with existing relays/contactors
BENEFITS
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Reduction in service maintenance costs
Could be used in other aero GFI applications
Meets FAA’s detection and trip specifications
Visual indicator to alert maintenance that GFI has occurred
Minimized aircraft downtime, easy install, no modifications required
KC Type w/o GFI
DISTRIBUTION
Flame Enterprises
Main: (800) 854-2255
AOG Support: (301) 788-1649
flamecorp.com
Avnet / Electro-Air
Main: (800) 332-8638
AOG Support: (800) 332-8638
avnet.com
Peerless Electronics
Main: (800) 285-2121
peerlesselectronics.com
Rev. February 2016