Engineering CalculationEarthing Calculator - Earth Electrode Resistance & Conductor Size (IS 3043)
Work out the resistance of pipe or rod earth electrodes, how many you need in parallel, and the earth conductor size for the fault current.
Open the calculator →Formula
Single rod / pipe: R = ρ / (2πL) × ln(4L / d)
ρ = soil resistivity (Ω·m), L = electrode length (m), d = diameter (m)
Conductor size: S = (I × √t) / k
Worked example
Soil resistivity 50 Ω·m, 3 m long, 40 mm diameter pipe
R = 50 / (2π × 3) × ln(4×3 / 0.04) = 15.1 Ω
Where engineers use it
- Earth pits for transformers, DG sets and panels
- Lightning protection earthing
- Substation earth grid (IEEE 80 tool also included)
How to use
- Click Open the calculator. It runs free in your browser, on desktop or phone.
- Enter your values. Units and typical ranges are shown next to each input.
- Read the result and the step-by-step working, then print or add it to your Project BOQ.
Questions
What about a substation earth grid?
Use the Substation Earth Grid (IEEE 80) guided check, which works out step and touch voltages.