Dear Raghunathan,

In addition to Kasper's suggestion of a zener on the supply voltage, you might add a huge-honking 500V filter cap (to the 24 V supply) to help absorb the surge before the fast-acting-super-duper-high-speed fuse can blow. And by huge-honking I mean a physically large, with lots of capacitance. If there's room in the box for 415V, there should be room for a hugh-honking cap.

Other than that I would just look into finding the fastest acting circuit breakers I could.

Joe