Wet leakage current Testing equipment purpose To evaluate the insulation of the module under wet operating conditions and verify that moisture from rain, fog , dew or melted snow does not enter the active parts of the module circuitry, where it might cause corrosion, a ground fault or a safety hazard
Wet leakage current testing equipment Apparatus a) A shallow trough or tank of sufficient size to enable the module with frame to be placed in the solution in a flat , horizontal position. it shall contain a water/wetting agent solution meeting the following requirements :
Resistivity : 3500Ω.cm or less Surface tension : 0.03N.mˉ1 or less Temperature :22oC±3oC The depth of the solution shall be sufficient to cover all surfaces except junction box
b) spray equipment containing the smae solution c) DC voltage source, with current limitation, capable of applying 500V or the maximum rated system voltage of the module , whichever is more d) instrument to measure insulation resistance
Wet leakage current testing equipment procedure All connections shall be representative of the recommended field wiring installation and precautions shall be taken to ensure that leakage currents do not originate from the instrumentation wiring attached to the module
a) immerse the module in the tank of th required solution to a depth sufficient to cover all suface except junction box enteries not designed for immersion. the cable entries shall be thoroughly sprayed with solution. if the module is provided with a mating connector , the connector should be immersed during the test
b) Connect the shorted output terminals of the module to the positive terminal of the test equipment , connect the liquid test solution to the negative terminal of the test equipment using a suitable metallic conductor
c) increase the voltage applied by the test equipment at a rate not to exceed 500V.sˉ1 to 500v or the maximum system voltage for the module , whichever is greater , maintain the voltage at this level for 2 min. then determine the insulation resistance
d)Reduce the applied voltage to zero and short-circuit the terminals of the test equipment to discharge the voltage build-up on the module
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