Following the tragic loss of member’s coaches and the resulting
discussion we all need to keep in mind that maintenance and inspections are
very important. Fuses and circuit breakers will not protect from this
kind of fire in all cases. Insulation failures caused by abrasion are not
always going to draw enough current to trip a breaker or blow a fuse.
Dirt, paint, melting insulation all create resistance which limits current flow
and creates HEAT. A good solid short would burn the wire apart or blow up
the batteries. Bad connections can also create heat just as a short can.
I had some insulation burn in our Wanderlodge due to a poor crimp on a 12v buss
in the left middle load center. After that I turned on all accessories
and found three more just by running my fingers over connections. I later
found two more with an inferred temperature probe. My point of all this
is fuses and circuit breakers can protect from current in excess of design
limits of a circuit, but you can start a fire without exceeding these limits.