Short answer: solar PV string protection should match DC voltage, string current, MC4 connector type, PV cable size, SPD rating, fuse rating and combiner box design.
| PV DC SPD | Select by 1000V or 1500V DC system voltage, discharge current and protection level. |
|---|---|
| String fuse | Confirm fuse current according to string design and module short-circuit current. |
| MC4 connector | Match connector voltage, current, cable range and compatibility approval. |
| PV cable and gland | Confirm cable size, UV resistance, insulation class, cable entry and IP rating. |
PV string protection should not mix 1000V and 1500V parts without design approval. DC voltage rating must be checked for every component.