Connector mismatch

Connector mismatch means a male DC connector from one manufacturer or type is mated with a female connector from a different one. It can happen between modules, between strings or arrays, or at the inverter. There is no standard that sets PV connector dimensions and tolerances, so connectors sold as compatible can look alike and seem to fit while still differing slightly in design. These small design differences can make the connection less tight against water and vapour. Mismatched materials in the metal contact, gaskets or seals can also cause problems, either through chemical incompatibility or different thermal expansion. Forcing different connector types together is a typical cause of connector defects. A weak connection like this can lead to resistance heating, ground faults, arcing and fire. Mismatches are most common at the string end where extension cables are used. They also occur when an inverter or string combiner box is delivered with incompatible connectors. Mismatched connectors are found by visual inspection, with infrared thermography as a supporting check. To prevent mismatches, check the supplier or the module and inverter spec sheets for the connector type. Only mate connectors from the same manufacturer that are certified as compatible, and make sure modules and inverters are delivered with the same connectors. Keep spare connectors and string cables that match the module connector type. Replace any connectors that do not match.