Sizing Inline Fuses for Parallel Solar Panels: Preventing Rooftop Fires

1. Sizing Fuses for Parallel Arrays

When wiring three or more solar strings in parallel, a fault in one panel can cause other panels to dump current into it, overheating the cables. Inline fuses are required.

2. Sizing Calculations

Size inline fuses at 1.56 times the panel's short-circuit current (Isc) rating. This provides a safety buffer while ensuring fast trip response in short-circuits.

3. Waterproof MC4 Fuse Connectors

Use high-quality waterproof MC4 inline fuse holders on the rooftop. Secure cables with UV-resistant clips to prevent water immersion damage.