Loop Impedance Calculator: Fault

Make a second table:

| Supply type | Typical Ze (Ω) | |-------------|----------------| | TN-S | 0.2 – 0.8 | | TN-C-S (PME) | 0.35 max | | TT | 10 – 20 | fault loop impedance calculator

If a calculator determines your $Z_s$ is too high (exceeds the max limit for your breaker): Make a second table: | Supply type |

Fault loop impedance, also known as the earth fault loop impedance, is the total impedance of the path that an electrical current takes when a fault occurs between a live conductor and the earth. It's a critical parameter in electrical safety, as it determines the magnitude of the fault current and the effectiveness of the protective devices, such as circuit breakers and fuses. fault loop impedance calculator

(Add conversion for higher temps: multiply by 1.2 for operating temp)

Standard resistance tables (mΩ/m) usually list: