A reliable earthing cable size calculator will ask for the following parameters:
A 415V industrial panel has a prospective earth fault current of 15 kA. The upstream MCCB trips in 0.1 seconds. The earthing conductor is copper with PVC insulation (k = 143). Find the minimum size. earthing cable size calculator
S=I2×tkcap S equals the fraction with numerator the square root of cap I squared cross t end-root and denominator k end-fraction : Minimum cross-sectional area ( mm2mm squared : Fault current in Amperes. A reliable earthing cable size calculator will ask
Most electrical standards provide a simplified table for sizing earth cables, often relating the earth size directly to the phase (live) conductor size. Find the minimum size
For IT earthing (clean earths) or lightning protection, the size calculation changes. Lightning protection earths must handle massive impulse currents, often requiring a minimum of 25mm² or 50mm² copper strip, regardless of the power cable size. A standard calculator for power circuits will not suffice for lightning protection—ensure you are using the correct tool for the job.