Coil of the cooking heater overheats and burn out very often?

The coil usually burn at the points circled in red near the power connection. We have 240V electric supply.which the wire support it says.we don’t have switch for ON-OFF for heater,we just use hooking.Should I use MCB instead of simple switch will it reduce sparking.
Please don’t tell me to increase the number of turn it will definitely reduce the heat of the heater.
Thank you, so much for your precious time.