As you all know, a troll hijacked one of my posts and kept insisting that
omitting a neutral on a pure 240v circuit would cause a fire, which would
invalidate the insurance.
But that brought up the question in my mind, can improper wiring actually
cause a fire?

Presumably any fool is capable of using the right gauge cable and breaker
for the current, terminating all cables in junction boxes, using a suitable
cover on the boxes, and securing the cable so it won't rip out of the box.
Given that, could doing anything improper actually result in a fire? Seems
to me that errors will result in the circuit not working, or a problem occur
in the (presumably) fire resistant boxes.
Given those basics being done right; what errors would result in fires?

(I suppose one example might come from my cottage. It has cable entering
the back of a kitchen cabinet and then going up to, and across the top. A
mouse chewed through the wire to get into the cabinet and short circuited
it, inches away from a pile of paper napkins. Seeing what happened to the
mouse, I have to think I was lucky it didn't catch the napkins on fire.
Obviously the cable shouldn't have been in the cabinet.)