High wet leakage current

This signature is a module leakage current to ground that is higher than usual when the module is measured wet in a wet leakage test. Modules showing snail tracks tend to have high leakage currents in wet leakage testing. In the test, a voltage is applied between the shorted module leads and ground, and the leakage current is read across a resistor to ground or from a metering high voltage supply. Current flowing from the module to ground can increase greatly when the module is wet from dew or rain, so separate wet and dry readings before comparing them. High leakage current is linked to potential induced degradation, and excessive leakage current has sometimes come with corrosion and delamination of the module materials. Leakage current alone is not a universal indicator of degradation, because some current paths into the module do more damage than others. The snail track discoloration itself is not known to cause a measurable power loss, but the cell cracks it reveals can reduce module power.

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• sentence 1: support check: partial - Passages say snail-track modules tend toward high leakage currents in wet leakage testing, but not that this is a signature defined as leakage higher than usual to ground.
• sentence 3: support check: partial - The passage describes voltage applied via shorted leads with current read across a resistor to ground or by metering high voltage supplies, but does not say 'between the shorted leads and ground' explicitly.
• sentence 4: support check: partial - Current transfer increasing greatly when wet and the need to distinguish wet from dry are stated, but the advice to separate readings before comparing is only implied for modelling. -->