As part of the standards for BS 7671 it states:
A device which disconnects the charging point from the live conductors of the supply and from protective earth in accordance with Regulation 518.104.22.168(ii) within 5 s in the event of the voltage between the circuit protective conductor and Earth exceeding 70 V rms. The device shall not operate if the voltage exceeds 70 V rms for less than 4 s. The device shall provide isolation. Closing or resetting of the device shall be by manual means only. Equivalent functionality could be included within the charging equipment.
I have a device which needs testing and falls under this category. Therefore, I am wondering how to replicate this fault condition safely. Presently I'am thinking of using a SPDT switch that when toggled connects a line connection(One of the phases) to the neutral via a resistor.
I am not sure however, what size the resistor should be to make it 70Vrms or if this is the correct method. Note the input power is 3 Phase AC 230Vrms.