Corroded connector contacts

Corrosion is usually found on the metal contacts once a DC connector is opened. The same defect can also make the connector or cable look melted, burned, brittle, broken, cracked or whitened. When a thermography check is done, affected connectors very often show overheating or hot spots at an early stage. In the first phase of a connector defect, series resistance rises and gives off heat that IR images can pick up. The rise may still be too small to detect electrically or by eye. Contact resistance follows three stages: an initial settling stage, a stable stage, and a final accelerated aging stage in which resistance climbs quickly as the connector reaches end of life. A connector that keeps degrading can cause intermittent low insulation faults that change with humidity. It can end in a ground fault, or in a burst connector that opens the string circuit. In module junction boxes, moisture getting in through damaged or missing seals corrodes the contacts. This is a sign of junction box interconnection failure and can lead to performance loss and arcing. Look for this signature mainly by visual inspection, with infrared inspection as a supporting check. Check connectors for discoloration or degradation, and replace damaged connectors or corroded contacts.

<!-- review notes

• sentence 7: support check: partial - Detection VI with (IRT) in parentheses and the check/replace instruction are supported, but the instruction comes from a Sunny Central torque section, not a general connector-defect statement; 'supporting' IR is implied only by the parentheses.
• sentence 1: review: partial - The passage says opened connectors 'can demonstrate corrosion', not that corrosion is 'usually' found; the melted, burned, brittle, broken, cracked or whitened appearance is supported. -->