Proper junction box sealing

Proper junction box sealing is a preventive action at the junction box supplier level that helps limit junction box failures. It mainly targets moisture ingress, which corrodes the connections and the cell string interconnectors inside the box. A junction box with an inadequate IP rating can also let water in and fail. The IEC 62790 standard sets design and test requirements for PV junction boxes, including a minimum IP55 protection rating. In the field, check the sealing around the wire entrance and the lid. It may be squeezed, broken or brittle, or missing completely. Also check whether the adhesive holding the box to the backsheet has weathered or yellowed. Sealing defects found during inspection should be corrected. Where there is evidence of arcing or burning, isolating the circuit for safety comes first. Sealing does not cover every path for water: delamination near the junction box can let water in, and proper lamination helps reduce this. If a junction box has already failed, replace the module rather than repair it, because repaired junction boxes can easily start new fires.

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• sentence 2: support check: partial - The passages say moisture ingress corrodes the connections and cell string interconnectors, and that an inadequate IP rating may cause water intrusion and failure. They do not say that sealing mainly targets moisture ingress.
• sentence 6: support check: partial - The passages say delamination near the junction box can induce water ingress, and that proper lamination reduces water ingress likelihood. They do not say that sealing fails to cover this path. -->