These improved results are obtained with the construction of this invention by interconnecting, as a single operating unit, two or more circuit breaker type electric switches which are electrically connected in series relationship and both of which will open simultaneously upon the occurrence of a predetermined current overload, so that a unit is provided which is capable of interrupting currents at higher voltages because the total air gap between the stationary and moveable contacts is at least doubled when compared to a single circuit breaker type switch.