We have reviewed all the production data of these 12pcs modules, there is no abnormal of the modules before shipment. Furthermore, we found the 12pcs defective modules are from 11 different pallets, and 75% modules are located on the top of each pallet, the modules were produced in different working days, so we think the junction boxes of the defective modules were from different batches.
At the same time, we query the Thailand weather of August, 2012, there are 24 days were raining. Because some pallets have been unpacked in site, the top ones would be soaked in water during installation when raining.
As we know, the protect class of JB is IP65, which can’t bear soaking in water, if the JB are soaked in water, the water will permeate through JB and cause JB corrosion. So we suspect that the modules got wet in rain during installation is the mainly reason for corrosive box. The details please refer to attached report.