Whohoo! I finally post to the wreck. My apologies in advance for the
googlegroups thing, the usenet server that I use doesnt allow posting,
and I'm too broke to afford a nice subscription to a decent server.

Anyways, My parents had a house built in 1997 (when I was 16 years
old). There have been two "near fire" incidents since it was built, on
120v circuits.

The first involved a pathetic "power strip" unit on the end of a
bar-style counter in the kitchen. The electrician installed this
pathetic plastic rail that was 14" long, and only containted two
outlets.One outlet would make intermittent contact, the other was fine.
One day in 1998, the unit started smoking a bit, the tripped the
breaker. I am quite a handyman, and amateur electronics technician, and
have had moderate experience with practical wiring, so I opened the
unit up to take a look at it. The bare ground wire had a nice crimped
plastic-insulated connector on it (in a matching beige color) and was
in fine shape. I don't know what the electrician did with the other two
plastic crimp-connectors (that I assume came with the unit) but he had
used wire nuts to connect the hot and neutral pigtails to their
respective wires (The outlet had pigtails, rather than screws or
backstabs). The wire nuts were a hair too large to fit into the plastic
rail, so he had taken a knife and trimmed the sides of the wirenuts
down. Over time, twisting plugs around inside the intermittent outlet
had caused the exposed metal edges of the wirenuts to brush against
each other, creating an arc between the hot and neutral lines. This
make some good smoke and melted the plastic rail housing a little bit.
(That same electrician installed lights in my father's woodshop with a
constant hot, a switched ground used as a neutral, and an un-connected
neutral, which we noticed and fixed before there was any noticable
problem.)

I replaced that mess with a plain old computer-style power-strip, with
the plug snipped off, and attached with good wirenuts and secured with
a big wad of electrical tape. It has been much more useful and
reliable, for the past 8 years.

The other incident was in the attic, which my parents decided to have
finished in 1999, into an "apartment style" space (with a bedroom,
kitchen, bathroom, and livingroom). I did the entirety of the
electrical wiring and electrical finish work, with the help of a BORG
how-to electrical code book, and some internet state-specific
electrical code research. It was inspected by a county electrical
inspector, and passed.

A little over a year ago, (after I had gotten married and moved out) my
parents and little brother were watching a movie in the attic
family-room. My mother plugged a circulating-oil-heater into an outlet,
and a different outlet, behind a couch, started smoking. After
dissecting the situation, we found a good third of the blue plastic
outlet box had melted, and half of the outlet itself had disintegrated.
I had chained the outlets from that breaker together, and that outlet
had been the weak link in the chain. It had one cable running in from
the previous outlet, and another running on to the next outlet. I had
bent a hook in the ends of the wires and stacked the two hooks onto
each of the screws (I dont trust the backstab system). That was
acceptable according to the inspector. The small contact area between
the two neutral wires had not been a problem until that higher-current
heater was plugged in, at which point it had exceeded the
current-carrying capacity of a contact point with such small
dimensions. It proceeded to overheat, melt, arc and destroy stuff.
20/20 hindsight has helped me realize that it's a very good idea to
throw a wire-nut onto situations where there is more than one wire, and
run a single-wire pigtail out to the screw contact.

The damage was done to the side of the outlet box AWAY from the 2x4
stud, thankfully, partially due to my father's instruction to install
the outlets "upside down" so they didn't look like a smiley-face and
tempt small children. Had it happened on the hot lead, or had the
outlet been installed the other direction, we would most likely have
had a fire (according to several expert and experienced opinions).

So yes, it's quite possible for even minor wiring problems to cause
fires.

Spott

Toller wrote:
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.)