Look for a damaged or missing seal on the module junction box, mainly around the wire entrance and the lid. The sealing material may be squeezed, broken, brittle or gone. Field inspection checklists record a leaking seal as a junction box defect, along with loose or fallen-off lids, cracked boxes and brittle adhesive. A bad seal lets moisture into the junction box, and the moisture corrodes the contacts. This can lead to junction box interconnection failure. Corroded or loose contacts can heat up, which shows as a hotspot on an IR camera. In the worst case they can short or arc and start a fire. Start with a visual and thermal check of the junction box. Check the bypass diodes, and use IV tracing and insulation checks if you suspect damage. Fix sealing defects or replace the damaged junction box assembly or module. If you see arcing or burn marks, isolate the circuit for safety first. Inverter enclosure seals can also be damaged if the enclosure is opened in freezing weather. Moisture can then get in, so remove any ice from the seal before opening.
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observed_asc1 verified · fact Open or detached junction box
On visual inspection, the sealing around the wire entrance or the lid may be squeezed, broken, brittle or missing altogether. This often goes with an open or loose lid or a junction box that has shifted on the backsheet.
tbl=17.r1 h=2f54f0d00dadtbl=36.r1 h=2f54f0d00dadverified by: review-workflowverified on: 2026-10-20
c2 drafted · lead Loose or corroded terminals
If the seal at the wire entrance or housing is missing or damaged, moisture can get into the junction box and corrode the contacts.
sec=h37 h=abafe13c83d7tbl=37.r3 h=69aa96116e44c3 drafted · lead Junction box seal leak
Field documentation checklists list a leaking seal as one of the junction box defect options.
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