Starting situation
A PV string was connected to the inverter through MC4 connectors. Other inputs could keep producing while one string stopped, so the whole system did not visibly shut down.
Real troubleshooting behind a failed string
A burned MC4 connector was behind the failed string
The connector burned internally. The system kept producing, but with one fewer string, and nothing outside made the loss obvious.
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PV-input monitoring can reveal the failed string; proving that a burned MC4 connector caused it requires safe on-site troubleshooting.
The problem
On-site inspection found that an internal metal contact had not formed a complete connection during installation. Higher resistance generated heat under load until the connector burned and opened the circuit.
What became visible
The first reliable symptom was loss of production on the affected string, not proof of the connector fault itself. Incomplete locking of connector halves can create a similar hazardous process.
SM Sentinel's role
Where the inverter exposes the required PV-input data, SM Sentinel can flag that a monitored string has stopped producing. Troubleshooting can then start from the affected input, while on-site inspection confirms the physical cause.
Human next step
Qualified personnel must safely isolate and inspect the DC side, replace damaged connector and cable sections, and verify compatible parts, correct crimping and complete engagement.
Expected operational outcome
The burnt connector and damaged cable section were replaced. After safety checks, the string produced again. One defective DC connection had caused partial production loss and serious heat damage without stopping the inverter.
What is this story based on?
A real MC4 fault that was found and repaired. The anonymized professional case may later be supported with approved photographs and measurements.
Service boundary
SM Sentinel does not measure connector temperature or see its physical condition, and cannot guarantee early detection of overheating. Cause confirmation and safe repair require qualified on-site inspection.
NEXT STEP
Find out what we can see from your system.
After connection, you can make a clearer choice about which SM Sentinel plan fits your operation.