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Grounding and surge protection
Installation4 min readUpdated: 2026-08
Grounding protects people against insulation faults and gives surge protection a reference path. It covers two distinct aspects: grounding of metallic frames (panel frames, structure) and lightning surge protection.
| Element | Role | Target |
|---|---|---|
| Ground rod | Low-impedance path to earth | Ground resistance < 25 Ω generally (check local code) |
| Equipotential bonding | Connects panel frames, structure, enclosures | Electrical continuity across the whole installation |
| DC surge protection (SPD type 2) | Clamps overvoltages on the panel side | Recommended if outdoor PV cables > 10m |
| AC surge protection | Protects inverter and grid-side equipment | Strongly recommended in storm-prone areas |
In areas with heavy thunderstorm activity (Central Africa, tropical zones), missing surge protection is a frequent cause of inverter destruction during the rainy season. An SPD costs far less than an inverter.
If a single ground rod doesn't reach the target resistance (dry, sandy, or rocky soil), several rods bonded in parallel and spaced apart reduce the overall resistance.
Common mistakes
- Skipping surge protection in a storm-prone area to cut the budget
- Bonding panel grounding to neutral instead of a dedicated ground rod
- Never measuring the actual ground resistance after installation
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