Most modern surge strips and house protectors have circuit breakers and temperature fuses to prevent serious consequences. A thermal fuse disconnects the MOV when it gets too hot. Only the MOV is disconnected leaving the rest of the circuit working but not protected. Often there is a LED light to indicate if the MOVs are still functioning. Older surge strips had no thermal fuse and relied on a 10 or 15 amp circuit breaker which usually blew only after the MOVs had smoked, burned, popped, melted and permanently shorted.