IEC 60990 Figure 3 and 4 Circuit

IEC 60990 outlines specific circuits for measuring touch current, particularly in Figures 3 and 4. These figures are essential for verifying the safety of electrical devices by assessing the leakage currents that could potentially flow through the human body.

Overview of IEC 60990 Figures

Figure 3: Unweighted Touch Current Circuit

Purpose: This circuit is designed to measure unweighted touch currents, which represent the current that could flow through a person when they come into contact with an electrically energized part.
Components: The circuit typically includes a measuring network that simulates the impedance of the human body, allowing for accurate assessments of touch current levels
Application: Used primarily in the testing of electrical equipment to ensure compliance with safety standards, particularly in environments where users may come into contact with exposed conductive parts

Figure 4: Weighted Touch Current Circuit

Purpose: This circuit is used to measure weighted touch currents, which take into account the frequency and duration of exposure to electric current.
Components: Similar to Figure 3 but incorporates additional elements to modify the measurement based on frequency response, reflecting more realistic conditions under which a user might experience electric shock
Application: Essential for evaluating equipment under conditions that mimic real-world usage, ensuring that devices are safe for consumer use

Importance of These Circuits

The circuits defined in IEC 60990 are vital for:

Safety Compliance: Ensuring that electrical devices meet international safety standards.
Calibration Verification: Providing a standardized method for testing and calibrating grounding continuity testers and other safety equipment
Consumer Protection: Reducing the risk of electric shock and ensuring safe usage of electrical appliances.

These measurements are crucial for manufacturers and certification bodies to validate that their products are safe for end-users.