Calculation Results
This calculator uses the formula based on IEC 60949 standards for determining earth conductor size based on thermal considerations during fault conditions.
The Earth Conductor Size Calculator helps you determine the right size of conductor (grounding wire) required to safely carry fault current during an electrical fault. Choosing the correct size is essential for protecting people and equipment from electric shocks or fires.
Why Earth Conductor Sizing Is Important
Proper earthing ensures that fault currents have a safe path to ground. An undersized conductor can overheat and fail, while an oversized one adds unnecessary cost. This calculator ensures a safe and economical choice.
Formula for Earth Conductor Size
The sizing formula is based on the energy let-through principle:
S = √(I² × t) / k
- S: Cross-sectional area (mm²)
- I: Fault current (A)
- t: Duration of the fault (seconds)
- k: Constant based on material (e.g., 143 for copper, 95 for aluminum)
Fault Current = 10,000A
Fault Duration = 0.5s
Material = Copper (k = 143)
S = √(10,000² × 0.5) / 143 = √(50,000,000) / 143 ≈ 4947 / 143 ≈ 34.6 mm²
You can round it up to 35 mm² copper conductor.
Materials and k-Factors
- Copper: k = 143
- Aluminum: k = 95
Applications
- Industrial power systems
- Residential and commercial earthing
- Generator and transformer grounding
- Electrical panel and substation safety
Conclusion
Use this Earth Conductor Size Calculator to make sure your grounding system meets safety standards. A correctly sized earth wire helps prevent electric shock, limits voltage surges, and protects your entire electrical setup. Always round up to the nearest standard size and refer to your local electrical code.