Ground Fault Locator GFL-1000

Model # GFL-1000

The Eagle Eye GFL-1000 Ground Fault Locator is an essential instrument to pinpoint faulty grounding where electrical cables have breakage and loss to the ground. The unit measures current leakage of DC systems with high resistance. The GFL-1000 is designed to fast-detect, track, and locate virtual grounding faults for both offline and online DC systems. Measurement of online DC systems is possible as the output current of the GFL-1000 is very low but the output voltage can be up to 1000V. The GFL-1000 battery ground fault locator provides accurate solutions for troubleshooting and preventative maintenance, increasing the reliability of electrical equipment. Fast localization and elimination of grounding faults is critical for electricians and service technicians whose goal is to increase system reliability.

The Eagle Eye GFL-1000 pinpoints ground faults by accurately measuring grounding resistance and distributing capacitance. Based on different distributing capacitance, it selects the right output frequency for testing - enabling it to be used on a variety of DC systems.

The GFL-1000 has a compact and rugged design making it easy to use in small places and harsh environments. The GFL-1000 Ground Fault Locator is widely used in the telecom, utilities, and transportation industries.

The GFL-1000 Kit Includes:

  • GFL-1000 Main Body Signal Generator
  • Power Adapter
  • Two (2) Signal Testing Leads
  • Two (2) Alligator Clips
  • Punctuation Clip
  • Signal Receiver
  • Two (2) Dual-Range Current Detector
  • Two (2) Batteries
  • Battery Charger
  • Carrying Case
  • User Manual

Utilities commonly use the GFL-1000 to meet NERC compliance. The GFL-1000 is recommended by NERC PRC-005-2 to inspect for unintentional grounds for Vented Lead-Acid, Valve-Regulated Lead-Acid, and NiCad batteries every four calendar months. In many cases, the first ground that appears on a battery is not a problem. Unintentional grounds that appear on the opposite pole become problematic, and it is up to the user to determine if corrective actions are needed on detected unintentional DC grounds to reduce any possible consequences.

  • Technical Specs
  • FAQs
  • Advantages
  • Applications

Technical Specs

Output Voltage:24, 48, 110, 220, 500, 1000 VDC
Output Frequency:10 Hz
Output Current Limitation:5 mA or Unlimited (max: 40 mA)
Fault Location Sensitivity:≤ 1 MΩ
Current Detect Sensitivity:AC/DC Circuit: ≥ 0.5 mA
Quick Search Clamp:55 mm (diameter), 60 mm (jaw opening)
Current Sensor:φ8 and φ20
Jaw Opening:60 mm (2.36 in)
Display:Backlit Color LCD
Operating Environment:Temperature: -5 – 40 °C (23 – 104 °F)
Power Requirements:8.4 VDC Li-ion Battery
Dimensions:360 x 260 x 135 mm (14.2 x 10.2 x 5.3 in)
Weight:7 kg (15.4 lbs)


Why should you measure battery ground faults?
Battery ground faults are often times difficult to locate and create costly and catastrophic consequences if they remain undetected. The entire battery system will be compromised and subject itself to overheating, thermal runaway, and reduced battery capacity while creating a hazardous work environment.

Can the GFL-1000 test AC Systems?
No, the GFL-1000 Ground Fault Locator will only test DC systems.

How does the GFL-1000 detect a fault?
The ground fault detector works by injecting an AC signal into the bus system with respect to ground using the signal generator. The signal path is then traced using current clamps connected to the signal receiver. The direction of current flow is indicated on the receiver display, enabling the clamps to be moved to another branch or section of wiring. The measurement is repeated, the clamps moved again until the faulty part of the circuit is located.

What are some typical kinds of faults the GFL-1000 can test for?
A typical supply to be tested will consist of a main bus connection with many branches to different loads or systems. Typical faults you may encounter are:

  • Fault from the positive bus to ground.
  • Fault from part of a load to ground.
  • Fault between bus bars (partial short circuit).
  • Fault from a branch to ground.
  • Fault from bus to a separate circuit (‘Wire Mix’ connection).
  • Leakage capacitance (This is not a fault, but leakage capacitance may be distributed around the system and will influence measurement).
In all cases, the actual impedance (resistance) of the fault may be very high, very low due to a short circuit, or anywhere in between.

How is the GFL-1000 powered?
Both the signal generator and signal receiver use rechargeable batteries that can be charged using power supplies which are included in the GFL-1000 package. The state of charge for each unit is indicated by the icon in the top right hand corner of the unit’s display. Both units may be charged while switched off. When the units are fully charged an indicator on the power supply changes from red to green.

How long do the rechargeable batteries last on a full charge?
The batteries will last for approximately 4 hours in normal use.


  • Patented technology, pinpoint current leakage fault with grounding resistance lower than 1MΩ
  • Adjustable output frequency on signal receiver effectively avoids interference from DC system itself
  • Signal receiver with adjustable sensitivity in different location of circuit help judge current leakage quickly
  • Ground fault location for both offline and online DC systems
  • Direction (positive or reversed) indicator for current leak helps to quickly locate the faulty grounding
  • Waveform analysis will analyze the interference signal in the circuit
  • Wide output voltage and output frequency ranges allow the GFL-1000 to meet the needs of your electronic equipment
  • Built-in band pass filter to bypass different interference signals
  • Additional signal receivers can work simultaneously to narrow down the searching scope and find the faults quicker
  • Reflects the aging status - reducing maintenance and repair costs


  • Railway and Transit: signal, communication, and locomotive electric equipment
  • Power Utility: DC system with faulty grounding
  • Industrial Facilities: electric safety equipment for general power distribution applications
  • Telecommunication: electronic equipment with faulty grounding
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  • Model #

    Ground Fault Locator
    Range: 24-1000V, 1-325 Hz

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Companies We Serve
  • Duke EnergyBlack Hills Power
  • Xcel EnergyTennessee Valley Authority
  • EnersysExxon Mobil
  • Pennsylvania Power & LightHyundai Power
  • RaytheonSMUD