A surprising share of the inverter boards we repair are damaged by surges that proper earthing and SPDs would have stopped. Earthing is invisible until it fails — and when it fails, it is expensive.
Three earthings a solar plant needs
- Panel/frame earthing — the module mounting structure
- DC side earthing — DCDB, negative conductor as per design
- AC side earthing — inverter AC output, neutral earthing at the LT panel
Surge protection (SPD)
Type 1+2 SPDs at the DC and AC terminals divert lightning and grid surge energy away from the inverter. Without them, a nearby strike or grid switching surge reaches the input stage and control boards directly — one of the fastest ways to destroy an otherwise healthy inverter.
Earth resistance values to aim for
- Lightning arrester earth: typically ≤ 10 Ω (as per IS/IEC and LA design)
- Protective/panel earthing: ≤ 5 Ω commonly specified for solar plants
- Values rise in dry, rocky or sandy soil — pit maintenance and watering matter
Warning signs of earthing problems
- Recurring isolation/earth fault codes on the inverter
- RCD/ELCB tripping repeatedly
- Tingling on metal structures
- Corroded or loose earth strips and pits
- Repeated surge-related board failures
Frequently asked questions
Does earthing cause the inverter to trip?
Poor or incorrect earthing causes real earth leakage, which trips the inverter or RCD. Correct earthing stops nuisance tripping and protects the electronics.
How often should earth pits be tested?
Before monsoon annually, and after any electrical fault or lightning event. Resistance readings should be recorded each time.
Need a solar inverter repaired?
Share your inverter brand, model and error code — our technicians will guide you and share an estimate before any repair starts.