In my neighborhood once there was a event that causes much damage to electrical appliances. The red phase conductor peeled of and the peeled section of wire touched the yellow phase when wind blows . This continues happens touch then move away.

As soon as the connection between two phases make the speed of fan increases drastically.

Now I'm confused if there is line to line fault then voltage must be reduced from nominal level and if voltage is reduced then speed of any induction motor must drop. But on the other hand speed increases drastically. During line to line fault the neutral current must be zero so is there any chance of neutral voltage rise.

Secondly the mcb doesn't trip which means that current is within limit as mcb doesn't trip on overvoltage case.

So why there is overvoltage during this event.

Does the voltage of healthy phase rises during line to line fault.