3202 SMA — Reverse Polarity
At a glance
- Severity
- FAULT STOP
- Domain
- DC_SIDE
- Reference standard
- IEC 62548 / CEI 64-8 Sez. 712
- Product / context
- DC Polarity Reversed
What it means
A string is connected with reversed polarity to the inverter input, or a single module in the string is wired with swapped cables. The inverter detects negative voltage on the DC input and shuts down for protection.
Probable causes
- Wiring error during installation: positive cable connected to the negative terminal of the inverter.
- Single module in the string with swapped MC4 connectors (+ and - reversed).
- Incorrect cable labeling of string cables in the combiner box.
- Replacement of a module with reversed connection relative to the chain.
Where to start
WARNING: do not attempt to disconnect MC4 connectors under load with reversed polarity (arc risk). Open the DC disconnector first. Measure the voltage at the inverter DC terminals with a multimeter. Is the voltage negative?
Full guided diagnosis in the app
The diagnostic tree for this fault has 6 guided steps with measurements, checks and resolutions. You'll find it in ElectraIQ, one of the five IndexOS apps: free, works offline.
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