1. Importance of Leakage Current Detection

Leakage current detection is a critical component of electrical safety in modern power systems. With rapid urbanization, power networks have become increasingly complex—high-rise buildings with dense wiring, industrial equipment requiring frequent starts/stops, and grid-connected renewable energy systems all contribute to heightened risks of leakage currents caused by insulation aging, environmental humidity, and other factors.

Hazards of Leakage Currents Include:

Human Injury: Leakage currents passing through the human body to ground may cause harm.

Equipment Degradation: Persistent leakage currents accelerate insulation aging or damage, threatening personnel and property safety.

Fire Risks: Continuous leakage currents can overheat equipment, potentially triggering electrical fires.

Traditional detection methods (e.g., post-power-off multimeter measurements) are cumbersome, hazardous, and lack real-time monitoring capabilities for live systems.

Figure 1: Importance of Leakage Current Monitoring

2. What Is Leakage Current?

Leakage current, also known as residual current, refers to the difference between incoming and outgoing current in a power system: Ir = Iin − Iout. It indicates unintended current flow due to insulation faults, grounding issues, or equipment defects.

Figure 2: Causes of Leakage Current

3. Causes of Leakage Current

Insulation Deterioration: Aging or damaged insulation allows current to leak to ground.

Poor Grounding: Improperly grounded equipment or conductive contaminants create unintended leakage paths.

Ground Faults: Short circuits to ground generate significant leakage currents.

4. Rapid Measurement Methods for Load Current, Leakage Current, and Ground Leakage Current

Traditional methods require power interruption and physical disassembly, posing operational inefficiencies and safety risks. In confined spaces (e.g., underground substations or cable trays), conventional tools often fail due to accessibility limitations.

ETCR EM6640 Series Clamp Leakage Current Meters revolutionize detection:

Non-Contact Measurement: Safely clamp onto live wires for mA-level accuracy via electromagnetic induction.

Advanced CT Technology: Permalloy core with magnetic shielding ensures precision (±1.5% accuracy) and stability in harsh environments.

Versatility: Larger-jaw models (EM6670/EM6680) accommodate thick cables.

Applications: Power grids, telecommunications, railways, oil fields, and industrial facilities.

Figure 3: ETCR EM6640 Series Clamp Leakage Current Meter

5. Key Features of ETCR EM6640 Series

True RMS Measurement with filtering, max/min/avg values, harmonic analysis, and distortion rate testing.

Wide Frequency Range: 40Hz–1kHz for comprehensive electrical safety checks.

Dual-Layer Shielding: 10μA resolution with anti-interference capability.

Bluetooth Connectivity: Sync data to mobile apps for real-time monitoring and storage.

Built-In Lithium Battery: Long-lasting operation with LED flashlight functionality.

6. Leakage Current Measurement Principle

The meter detects alternating current (I) via electromagnetic induction:
I = n × I1
(n = turns ratio between primary and secondary coils)

By measuring the vector sum of three-phase currents, the device calculates leakage current magnitude to identify faults.

Figure 4: Leakage Current Measurement Principle

7. Case Study: Commercial Complex Substation

A substation experienced frequent overheating and leakage alarms. Using ETCR EM6640 Series, technicians identified faults without power disruption:

Single-Phase Two-Wire: 22.6mA leakage in A1 cabinet (Figure 5).

Three-phase three-wire leakage current measurement（Figure 6）

Three-Phase Four-Wire: 2.89A leakage in A3 cabinet (Figure 7)

Ground Line: 2.94A leakage in B2 cabinet (Figure 8)

Root Cause: Carbonized insulation from low-quality high-power devices.
Outcome: Temporary load redistribution and vendor rectification eliminated risks, reducing troubleshooting time by 70% and annual costs by 45%.

Figure 5-10: Measurement scenarios and Bluetooth/filtering functions.

8. Conclusion

The ETCR EM6640 Series enables efficient, safe leakage current detection, ensuring both operational continuity and regulatory compliance. Its adoption in preventive maintenance protocols has set industry benchmarks for electrical safety and cost efficiency.

About Guangdong ETCR Technology Co., Ltd.
With nearly 20 years of expertise, ETCR specializes in R&D and production of electrical testing instruments and power quality solutions. Custom OEM/ODM services are available to meet specific client needs.

Products:

ETCR EM6540 Clamp Meter

ETCR EM6670/EM6680 Large-Jaw Clamp Meters

Contact:

Hotline: +86 13802922567

Website: www.etcrmeter.com