Leakage Current Testing for Medical Equipment — Patient Safety Limits

Why Microamps Matter in Medical Equipment

In most industrial settings, a milliamp of leakage current is negligible. In medical equipment connected to a patient, the same current can be dangerous — current paths through the body, especially near the heart, have very low safety limits. Leakage current testing on medical devices verifies that earth, enclosure, and patient-applied-part leakage stay within the strict limits that protect patients.

1. Types of Leakage Current

• Earth leakage: current flowing in the protective earth conductor.
• Enclosure (touch) leakage: current from accessible parts to earth.
• Patient leakage: current through a patient-applied part.
• Patient auxiliary current: current between applied parts.

2. Why a Sensitive Leakage Clamp

A standard clamp meter resolves amps, not the microamps that medical limits demand. A dedicated leakage current clamp resolves down to microamps and rejects noise, so it can measure the tiny currents involved without breaking the circuit.

1. Microamp resolution for sub-milliamp limits.
2. True-RMS for waveform-independent accuracy.
3. Low-noise design to resolve small signals.
4. EK leakage-current clamps are built for this range.

3. Measuring Against Limits

• Identify the device classification and applied-part type.
• Apply the relevant limit from the device's safety standard family.
• Measure under normal and single-fault conditions where the procedure requires.
• Record each value against its limit.

4. Routine Test Intervals

Medical equipment is tested at commissioning and at defined intervals thereafter as part of biomedical engineering maintenance. Rising leakage over time signals insulation degradation and warrants investigation.

5. Documentation

• Record device ID, leakage type, measured value, and limit.
• Note normal vs single-fault condition.
• Attach the instrument calibration reference.
• Trend across test intervals.

EK Recommendation

EK leakage current clamps provide microamp resolution and true-RMS accuracy for medical and IT-equipment leakage testing. Talk to EK service teams for a biomedical-maintenance bundle.