What Is the Wet Leakage Test?
The Wet Leakage Test is a standardized test for the electrical safety of PV modules under moisture exposure.
The module is tested in a water bath or under simulated wet conditions for insulation weaknesses and leakage currents – according to standard IEC 61215-2 (MQT 13).
It is particularly important to ensure that used modules no longer pose a safety hazard when redeployed – for example in second-life applications or after transport, dismantling, and storage.
Why Is This Test So Crucial?
PV modules are exposed to the elements for decades – rain, dew, snow, and moisture are part of everyday operation.
Over the years, this can lead to:
- Microcracks in laminate or glass
- Corrosion of cell connectors or junction boxes
- Insulation degradation at edges or backsheet film
– often invisible from the outside, but electrically dangerous.
The Wet Leakage Test reliably shows whether:
- The module is still sufficiently protected against current flow through moisture
- There are insulation weaknesses that could pose a risk in operation
- The module meets the safety requirements for reinstallation
How Does the Wet Leakage Test Work at 2nd Cycle?
- Preparation: The module is placed in a water bath or wetted with a conductive solution
- Voltage application: A defined voltage (typically 500–1000 V DC) is applied between the active cell circuit and the grounded water/solution
- Leakage current measurement: The resulting leakage current is measured – it must remain below the limit value specified in the standard
- Evaluation: If the module passes the test, it is classified as electrically safe under wet conditions. If not, it is flagged as a safety risk
What Can the Wet Leakage Test Detect?
The test specifically identifies:
- Insulation failures in the laminate structure
- Damaged backsheet films or edge seals
- Corroded or defective junction boxes
- Moisture ingress into the module interior
These defects pose a real safety risk – especially when modules are reinstalled outdoors where rain and moisture are inevitable.
Wet Leakage Test as Part of Our Testing Line
At 2nd Cycle, the Wet Leakage Test is the final safety check in our fully automated testing process:
Visual inspection → Flash test → UV fluorescence → Electroluminescence → Wet Leakage Test
Only modules that pass all test stages – including the Wet Leakage Test – receive the "Reuse" grading. This test ensures that no module with electrical safety risks is returned to the market.
Conclusion
The Wet Leakage Test is an essential safety test for every used PV module. It ensures that modules are not only still powerful but also electrically safe under real-world weather conditions.
At 2nd Cycle, we perform this test as standard – because safety comes first.