This circuit is an Automatic Cut off Switch for Egg boiler. It connect the mains voltage when you press the push button for 1 second, then disconnect the mains when the thermal switch inside the egg boiler cuts off.
It is a latch circuit that reset itself in absence of current / power.
You have to wrap several turn of wire to increase the sensitivity of the current transformer.
Parts list:
Current transformer 2000:1
Solid state relay 2A or more (depends on your load)
LED
Capacitor 220uF 16V
Momentary push button switch 3A 250V
Plastic box enclosure
Circuit:
Watch this video for more details: