Yes, if one in one-hundred thousand thermal fuses fails to break circuit (o
n an average), and just one is in series to the circuit, and they sell a mi
llion units, They can expect to burn down ten homes by calculated chance, c
ould be more or less. Or P(fire)= 0.00001x1,000,000
But with two TF... P(F)=.00001x.00001x1,000,000=.0001
Or, having sold a million, there would be a 1:10,000 chance of any fires at
all. They'd have the probability that they could build ten-billion units b
efore burning one house. Life safety vs $0.99...worth it.