How to Calibrate Leakage Current Testers?

Introduction

Leakage current testing is a critical safety requirement for any electrical device, from household appliances and power tools to medical equipment and industrial machinery. To ensure that leakage current testers provide accurate, reliable readings, regular calibration against traceable standards is essential. This article explains what leakage current testers are, why calibration matters, and how TUNKIA’s dedicated calibration solutions deliver precision, efficiency, and portability for laboratories and manufacturers worldwide.

1. What is a Leakage Current Tester

1.1 What is Leakage Current?

Leakage current is the current that flows between electrically insulated metal parts or between live and grounded parts through surrounding media or insulation surfaces when a certain voltage is applied without faults. During proper operation, leakage current should remain below a specified threshold. However, design defects, insulation aging, or component failures can cause leakage current to exceed safe limits, leading to electric shock hazards or more severe accidents.

1.2 What is a Leakage Current Tester?

A leakage current tester is a safety instrument specifically designed to measure leakage current. It is widely used in the production and quality control of various electrical devices, including:

• Industrial equipment

• Electronic instruments

• Medical devices

• Household appliances

• Lighting fixtures

• Power tools

1.3 Classification of Leakage Current Testers

Leakage current testers can be classified by application into: non-medical testers and medical testers.

2. Understanding Body Impedance in Leakage Testing

2.1 Body Impedance

· Body Impedance: The total impedance of the human body includes resistance and capacitance from the skin, blood, muscles, tissues, and connective parts. The total body impedance (Zr) the vector sum of internal impedance (Zi) and skin impedance (Zs).

· Impedance Behavior: The body's total impedance decreases with increasing voltage and increases with higher frequency.

2.2 Impedance Network of Testing Instruments

 · Standards such as IEC 60990 and GB/T 12113 specify various human impedance network models composed of resistors and capacitors.

· Typically, leakage current testers are equipped with these impedance networks to measure leakage currents by simulating the touch of a human body on the device's outer shell. This setup provides a realistic reflection of the device's insulation condition.

Therefore, calibration procedures include impedance network measurements to ensure that the built-in impedance networks of the testers meet standard requirements.

3. Why Calibration of Leakage Current Testers is Essential

Leakage current is a crucial parameter in the safety performance of electrical equipment. The leakage current tester, used to measure this parameter, is an essential metrological tool. Its measurements directly impact product quality and user safety. To ensure that products meet insulation protection requirements, it is necessary to calibrate the tester either before use or periodically, to guarantee accuracy and performance.

Leakage current is a critical safety parameter for all electrical equipment. The leakage current tester, as the instrument that measures this parameter, is an essential metrological tool. Its accuracy directly impacts:

• Product quality – Incorrect measurements can lead to faulty products passing quality control

• User safety – Underestimated leakage current can result in electric shock hazards

• Regulatory compliance – Non-compliant testers may cause failed audits or product recalls

To ensure that electrical products meet insulation protection requirements, leakage current testers must be calibrated before first use and periodically thereafter.

4. Verification Regulations and Test Items of Leakage Current Testers

The table below presents the standards system applicable to leakage current testing. Notably, the new verification regulations for leakage current testers — JJG 843-2022 and JJG 1188-2022 — officially took effect in early June 2023.

The following table shows the test items listed in the verification regulations and verification methods and standards required.

5. TUNKIA Leakage Current Tester Calibration Solution

5.1 TUNKIA Solutions

TUNKIA offers dedicated calibration systems for leakage current testers:

Unlike traditional multi-instrument solutions that require combining separate current sources, voltage sources, resistance meters, and impedance testers, TUNKIA’s TD1210 series integrates multiple functions into a single, compact device.

Built-in functions include:

• Wide-band constant current source

• Wide-band constant voltage source

• DC resistance meter

• Impedance tester

• AC voltage standard meter

Technical Specifications of TUNKIA Leakage Current Tester Calibration Device:

5.2 TD1210A Leakage Current Tester Calibration Device Advantages

5.3 Leakage Current Tester Calibration Device Operation Video

For a step-by-step demonstration of the TUNKIA leakage current tester calibration process, please refer to the operation video above.

6. Conclusion

Accurate leakage current measurement is not optional—it is a matter of user safety, product quality, and regulatory compliance. Regular calibration of leakage current testers ensures that electrical devices meet insulation protection requirements and that safety decisions are based on reliable data.

TUNKIA’s TD1210 and TD1210A calibration devices provide:

• All-in-one integration – No need for multiple separate instruments

• High efficiency – Simple wiring and unified operation

• Portability – Suitable for both laboratory and on-site use