I don't think that is needed. The technician who did this is an experienced guy and normally works very safe. Poor fellow is in a state of shock and will need counselling.

There was this 10HP motor that refused to start. Looking at the power contactor, it was evident that the 24V dc coil supply lug had worked loose. He was just trying to tighten it when, by accident the screw driver shaft touched the 415V ac terminal that was above the coil terminal.

Yes the right way would have been : A.Power down the HT before attempting service in such areas. B.Use a screw driver with an insulated shaft.

Coming back to the solutions offered, I think the crowbar IC MC3423 suggested by Erik looks promising. Maybe I can have this circuit added to every low voltage power supply in such panels. Also interesting was the capacitor idea by Joseph - can be tried out.

It has been comforting to read the posts.

Thanks.

Raghu