Cellular modems need high peak power (e.g., 6 W or 7 W) for wirelessly transmitting data over the cellular network. In order to operate in hazardous locations such as petrochemical industries, oil and gas pipelines, and certain automation plant environments, the fault power, current, voltage and energy dissipated in the cellular modem device needs to be limited to be within the ignition energy limits of a hazardous gas, and also the surface temperature of the cellular modem device under fault conditions needs to be limited to be within ignition temperature limits of hazardous gases. A simple known approach is using infallible resistors (film type resistors whose failure mode is only an open circuit) for power and current limiting and infallible zener diodes for limiting the voltage.