Its quite possible for even fused circuits to cause fires. If there is a high resistance short then it will heat up without drawing enough current to trip the

Its quite possible for even fused circuits to cause fires. If there is a high resistance short then it will heat up without drawing enough current to trip the fuse or breaker. I don't know how common this is in cars, but it is quite common in household wiring. It was especially problematic with aluminum wiring used in the 70s but can happen even in copper circuits.