When and who is permitted to test supply voltage of greater than 415 volts?

As we know that415V is related to Three Phase system.

To test this voltage, the person must be experienced, competent and the one who has tested before also.

He should know well whats the three phase system and what are the parameters on which it is based.

There are four main things he should know.

1- Insulation Testing

2- Loop Testing

3- RCD Testing

4- Phase Rotation Testing

The Person who knows well about these above things, is allowed to test the Three Phase System and Voltage.

Normally in running three phase system, We can check the voltage across each phase. i-e phase to phase voltage, then phase to Neutral and then phase to Earth by Multimeter setting on400V.

Also We can check the phase sequence at any time but with proper safety measures.