Is it possible to use the spike to control a large motor that consumes over 20Amps by switching the yellow 20Amps switch with a 30amps or 40amps circuit breaker ? or will it damage the internal connections?
Yes, but the SPIKE is only rated to 20 Amps and therefore should not be exposed to higher current levels. Exceeding the 20 Amp rating will greatly reduce the life of the SPIKE although it may work for a short period of time at higher current levels. The Specifications of the SPIKE are only valid when the current is limited to 20 Amps.