A flame sensor apparatus includes a sensor assembly. The sensor assembly includes a photodiode for sensing characteristics of a flame. The photodiode outputs an electrical photocurrent. The sensor assembly includes an electrical assembly that is electrically remote from the sensor assembly. The sensor assembly includes an electric cable assembly extending from the sensor assembly to the electrical assembly. The electric cable assembly includes an electrical cable to electrically convey the photocurrent to the electrical assembly. At least the sensor assembly is configured and constructed to experience and continue to operate at a temperature at or greater than 200° C.