Abstract: A float switch system for limiting to desirable levels current and energy entering a tank of combustible liquid comprises: a float switch disposed within the tank; an interface circuit external to the tank and coupled through wiring to the float switch; a passive transient suppression circuit coupled to the wiring external and in proximity to the tank, and operative to limit current and energy entering the tank over the wiring to the desirable levels; and a control circuit coupled to the float switch through the transient suppression circuit and to the interface circuit, the control circuit operative to monitor the status of the float switch with current within the desirable current level and to energize the interface circuit based on the switch status.