So the thermal overload isnt actually in the switch, the switch is controlling the thermal overload on whatever it is going to?Is this a thermal overload that you can interchange ? (different ratings)
If so, you probably actually have a manual motor starter.
They resemble a switch but have means to add a thermal motor overload heater.
See Pg 3
of link in next post
... by tripping the switch. As he said, it may LOOK like a regular toggle switch with a heater element, but it acts like a circuit breaker. The heater element is the current sensor that trips the switch if the motor load is too high.... and kills power to the motor...