About the Earthing / Grounding

Earthing (grounding) design for a solar plant sizes the earth conductors and electrodes so fault current is safely carried to ground, equipment is protected, and touch/step voltages stay within safe limits — as required by IS 3043 and CEA safety regulations.

How to calculate it

1. 1Determine the maximum earth-fault current and its duration from the protection settings.
2. 2Size the earthing conductor cross-section so it carries the fault current for the fault duration without exceeding its temperature limit (per IS 3043).
3. 3Design the earth electrode/pit or earth mat to achieve the target earth resistance (commonly ≤ 1 Ω for larger plants; per specification for rooftop).
4. 4Bond all module frames, structures, and equipment to the earthing system, and provide separate earthing for lightning protection where required.

Worked example

A plant with a 5 kA fault for 1 second typically uses a GI/copper earth strip sized to that adiabatic limit, with multiple earth pits in parallel to bring the combined resistance below 1 Ω.

What you can calculate

• IS 3043:2018
• Electrode count
• ≤1Ω resistance
• Touch voltage

Standards & references

Frequently asked questions