AS 4070-1992 (R2015) pdf free.Recommended practices for protection of low-voltage electrical installations and equipment in MEN systems from transient overvoltages. This Standard recommends a simple system of insulation coordination for nominal 240/415 V. 50 Hz electrical installations in multiple earthed neutral (MEN) systems to avoid damage to wiring and equipment due to transient voltages exceeding 2500 V caused by lightning...