Earthing Cable Size Calculator Exclusive Jun 2026

An incorrectly sized earth cable is not just a compliance failure; it is a latent hazard. If a fault occurs and the earth conductor is too small to handle the fault current, it can melt before the protective device (circuit breaker) trips. This leaves the exposed metalwork of an appliance live, creating a lethal shock risk.

The primary function of an earthing conductor is to provide a low-impedance path for fault current. This path must be robust enough to facilitate the rapid operation of the circuit's protective device. earthing cable size calculator

Selecting the correct earthing conductor size is not arbitrary—it is a critical calculation governed by international standards. An automates this process, applying formulas from standards such as IEC 60364-5-54 or BS 7671 (UK) and NEC Table 250.66 (US) to determine the minimum safe cross-sectional area (in mm² or AWG/kcmil). An incorrectly sized earth cable is not just

( S = \frac\sqrt15000^2 \times 0.1143 ) ( S = \frac15000 \times 0.316143 ) ( S = \frac4743143 \approx 33.2 \text mm^2 ) The primary function of an earthing conductor is

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.