Earth Electrode Resistance Calculator

Earth Electrode Resistance Calculator

This tool calculates earth electrode resistance using the fall-of-potential method.

Test Method

The 3-point or fall-of-potential method involves:

1. Earth electrode (E)
2. Current spike (C) placed 30-50m away
3. Potential spike (P) placed 62% of distance between E and C

E —— P —— C
(62% of total distance)

Voltage (V):

Current (A):

Distance E to C (m):

Distance E to P (m):

Soil Resistivity (Ω·m):

Test Results

Earth Electrode Resistance:

0 Ω

Recommended Maximum:

5 Ω

Interpretation

Measurement Tips

• Perform test in dry conditions for worst-case measurement
• Ensure spikes are firmly in the ground
• Use calibrated test equipment
• Repeat test with different P positions to verify

Note: This calculator provides an estimate. Actual measurements may vary based on soil conditions, electrode type, and installation quality. Always follow local regulations (e.g., BS 7430, IEEE 81).