Introduction
PV combiner boxes are robust, but like any electrical device, they can develop faults. Knowing the most common issues and how to address them ensures maximum uptime and system safety.
1. Overheating Inside the Combiner Box Cause: Poor ventilation, high ambient temperature, or undersized conductors.
Solution: Improve airflow, check conductor ratings, and avoid direct sunlight.
2. Frequent Fuse Blowing Cause: Short circuits or overloaded strings.
Solution: Inspect wiring and panel output. Replace with correct fuse rating.
3. SPD Failure Cause: Frequent surges or lightning strikes.
Solution: Replace SPD and consider additional external surge protection.
4. Loose Wiring Connections Cause: Vibration, poor installation.
Solution: Periodically check and tighten connections.
5. Water Ingress Cause: Poor sealing or damaged enclosure.
Solution: Ensure proper IP rating, reseal or replace the box.
6. Uneven Current Distribution Cause: Shading or mismatched strings.
Solution: Rebalance string configurations.
7. Intermittent Monitoring Failure Cause: Communication line interference.
Solution: Check communication modules and replace faulty wiring.
8. Burnt Busbars Cause: Overcurrent or corrosion.
Solution: Inspect load ratings, replace busbars, apply anti-corrosion paste.
9. Breaker Trip Without Apparent Cause Cause: Ground faults or insulation failure.
Solution: Test insulation, use megohm meter.
10. High Contact Resistance Cause: Oxidation at terminals.
Solution: Clean and apply contact grease.
Conclusion
Proactive maintenance and periodic inspection can prevent most PV combiner box issues. Use this checklist to ensure long-term system health.
