An overvoltage protection device comprising: first and second electrically conductive electrode members; a varistor member formed of a varistor material and electrically connected with each of the first and second electrode members; characterized in that the overvoltage protection device includes both: an integral first fail-safe mechanism configured to electrically short circuit the first and second electrode members about the varistor member when triggered by a first set of operating conditions; and an integral second fail-safe mechanism configured to electrically short circuit the first and second electrode members about the varistor member when triggered by a second set of operating conditions different from the first set of operating conditions, wherein the first set of operating conditions includes an arcing event; and the second set of operating conditions includes an overheating event the first fail-safe mechanism is operative to electrically short circuit the first and second electrode members about the varistor member in response to the varistor member conducting a relatively high fault current; and the second fail-safe mechanism is operative to electrically short circuit the first and second electrode members about the varistor member in response to the varistor member conducting a relatively low fault current that is insufficient to trigger the first fail-safe mechanism. first and second electrically conductive electrode members; a varistor member formed of a varistor material and electrically connected with each of the first and second electrode members; characterized in that the overvoltage protection device includes both: an integral first fail-safe mechanism configured to electrically short circuit the first and second electrode members about the varistor member when triggered by a first set of operating conditions; and an integral second fail-safe mechanism configured to electrically short circuit the first and second electrode members about the varistor member when triggered by a second set of operating conditions different from the first set of operating conditions, wherein the first set of operating conditions includes an arcing event; and the second set of operating conditions includes an overheating event the first fail-safe mechanism is operative to electrically short circuit the first and second electrode members about the varistor member in response to the varistor member conducting a relatively high fault current; and the second fail-safe mechanism is operative to electrically short circuit the first and second electrode members about the varistor member in response to the varistor member conducting a relatively low fault current that is insufficient to trigger the first fail-safe mechanism. an integral first fail-safe mechanism configured to electrically short circuit the first and second electrode members about the varistor member when triggered by a first set of operating conditions; and an integral second fail-safe mechanism configured to electrically short circuit the first and second electrode members about the varistor member when triggered by a second set of operating conditions different from the first set of operating conditions, wherein the first set of operating conditions includes an arcing event; and the second set of operating conditions includes an overheating event the first fail-safe mechanism is operative to electrically short circuit the first and second electrode members about the varistor member in response to the varistor member conducting a relatively high fault current; and the second fail-safe mechanism is operative to electrically short circuit the first and second electrode members about the varistor member in response to the varistor member conducting a relatively low fault current that is insufficient to trigger the first fail-safe mechanism. the first set of operating conditions includes an arcing event; and the second set of operating conditions includes an overheating event the first fail-safe mechanism is operative to electrically short circuit the first and second electrode members about the varistor member in response to the varistor member conducting a relatively high fault current; and the second fail-safe mechanism is operative to electrically short circuit the first and second electrode members about the varistor member in response to the varistor member conducting a relatively low fault current that is insufficient to trigger the first fail-safe mechanism.