Earthing conductor
Calculate a protective conductor thermal minimum using the applicable material, insulation and initial-temperature assumption.
Enable JavaScript for live calculations. Read the method and default example below.
Method and assumptions
- S = I × √t / k. The k value depends on the entered arrangement, material and insulation.
- This is a thermal minimum; mechanical minimums, PEN requirements, bonding rules, fault-loop impedance and electrode design need separate checks.
Before using the result
- Use actual protective-device let-through energy where applicable. Confirm that the assumed fault current and disconnection time describe the same fault condition.
Worked example
Illustrative default inputs. Enter your project values above.
- Fault current
- 12000 A
- Disconnection time
- 0.5 s
- Conductor material
- Copper
- Insulation
- XLPE — 90 °C
- Protective conductor arrangement
- Inside multicore cable
- Earthing system
- TN-S
Default results
- Adiabatic minimum
- 59.34 mm²
- Tabulated size candidate
- 70 mm²
- Material constant (k)
- 143
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Technical references
These references support planning. The exact model documentation and a project-specific engineering review govern the final specification.