Earth Fault Loop Impedance (max Ze) is the impedance of the earth fault current loop starting and ending at the point of earth fault.
The table below shows the maximum value of EFLI for new single and three phase supplies at the Point of Supply.
System | Service capacity | Earthing terminal | EFLI (at the customers supply terminals) |
230V single phase | Up to 100Amp | Cable sheath/continuous earth wire | 0.8W |
Up to 100Amp | PME/PNB | 0.35W | |
400V three phase | Up to 100Amp | Cable sheath/continuous earth wire | 0.8W |
Up to 200Amp | Cable sheath/PME/PNB | 0.35W | |
200-300Amp | Cable sheath/PME/PNB | 0.2W | |
Over 300Amp | Cable sheath/PME/PNB | 0.15W |
All of the quoted values of earth loop impedance shown above are typical maximum values and the measured value of EFLI will change depending on the network configuration due to alterations, faults, maintenance and any embedded generation.
V1_December2015