Applicable Systems
Sunny Boy
Symptoms
L and N swapped. The AC input line (L) and neutral (N) conductors are reversed. This is a dangerousinstallation error.
Possible Causes
- AC wiring L and N reversed at inverter terminal
- AC cable L and N conductors swapped at breaker panel
- Grid connection point with reversed polarity
- Previous service or maintenance reversed wiring
Troubleshooting Steps
- Step 1: Check the equipment status and fault indicators to confirm the active fault code
Fault indicator or HMI displays code 1001 as active - Step 2: Verify all electrical connections, wiring harnesses, and connector seating
All connections secure, no corrosion, loose pins, or damaged wires - Step 3: Measure the input power supply voltage at the equipment terminals with a multimeter
Voltage reading is within the equipment's specified operating range - Step 4: Inspect the power input wiring, breakers, and fuses for damage or degradation
Wiring intact, breakers closed, fuses continuous - Step 5: Check for transient voltage events or power quality issues using a power analyzer
No sustained overvoltage, undervoltage, or phase imbalance detected - Step 6: Reset the fault after correcting the power issue: fix root cause, then press RESET or power-cycle
Fault clears and equipment resumes normal operation
How to Reset
To reset: 1) Identify and fix the root cause described in the fault symptoms. 2) Press RESET on the HMI or controller, or power-cycle the equipment. 3) If the fault recurs, contact manufacturer service. Caution: Document the fault code and context before resetting.
Frequently Asked Questions
- Q: What does fault code 1001 mean on the SMA Sunny Boy?
Fault 1001 on the SMA Sunny Boy indicates: L and N swapped. The AC input line (L) and neutral (N) conductors are reversed. This is a dangerous installation error. Refer to the equipment manual and manufacturer support for specific troubleshooting steps.
- Q: Can I continue operating the equipment with fault 1001 active?
No. The equipment has detected a fault condition and has taken protective action (typically stopping or derating). Continuing to operate without fixing the root cause may cause further damage. Always investigate and fix the fault before resuming operation.
Source: SMA Sunny Boy Inverter Installation and Operation Manual, SMA Official Documentation
Category: PLC & VFD