marad,

You've ruled out windstorms but make no mention of lightning. If the barn
is old and in bad shape it's possible that the insulation on the wires is
also old and in bad shape. From your mention of trees and branches you
suggest that no one has been maintaining this service line. I don't think
that the breaker on a line transformer is intended to protect your service
lines. You should have the power company take a look, and replace or remove
this service line.

Good luck,
Dave M.

wrote in message
...
There is an old barn on my farm that needs serious repair and one of
those projects that I am always planning to get to, but never do.

Anyhow, I went out to the pasture today and was rather shocked when I
found the overhead triplex to that barn was nearly touching the
ground. On closer inspection, I found that of the 3 wires, only one
of the hot wires was still attached to the barn, and was hanging by
the service entrance head that was pulled off the building. The
neutral cable, and other hot wire was just dangling in a tree.

I shut off the main disconnect and had to do some tree trimming to
finally get to the wire. What I found was a spot where both the
neutral wire and the hot wire were melted at that spot, which is about
10 feet from the old barn. The 3rd wire, (still attached one), had a
little burn on the insulation, although not down to the bare wire.

Because there is no way to shut off the power to this one wire, I just
temporarily capped the end of the hot wire and propped a 12 foot 2x6
under the center of it, to keep some of the weight off and keep if off
the ground. Tomorrow I will (somehow) reattach it, or just remove it,
since it's not really needed.

You shut off the main disconnect and there is still power on the wire?

Call a pro immediately. Something is not correct.


Anyhow, I am puzzled how, or why it burned at that spot?????
It's been there for years. Although it's not used, it's been live,
and did not have a tree or anything else fall on it, nor did we have
any wind storms lately. Why would it burn thru, and not blow the main
breaker? This has me puzzled. Even if there was a little nick in the
insulation on the hot wire, why would it contact the neutral for no
apparent reason? I should note that the break occurred in the
branches of that tree. I do not see any burn spots of the tree, even
after I did some serious trimming on it. Is it possible that the tree
got wet (we just had a lot of rain), and the tree served as a short?
That's all I can figure. I should note also, that the wire is not
rubbed bare, like a tree branch was rubbing, it just burned cleanly in
half, both the neutral and that one hot wire. I just find this real
odd.

Mark

A original defect in the wire could have slowly worn through.
There is a hundred things that I can think of that MIGHT cause this problem
over time.

You never noticed a tripped or blown circuit breaker?

wrote:
....a long story about an old supply that shorted out for some reason...

There's absolutely no way to know what actually happened (or even when,
apparently). It could just as easily been some critter got across the
two lines which happened to have a bare spot from simply years of
aging--most of the really old overhead wires on our place are almost
bare simply from having been hanging there for 50 years or so...

If you have a disconnect on the pole but one phase isn't cut off, sounds
like something ain't right...

Whatever you do, be careful -- sounds like you're playing around w/ a
service entrance w/o having proper equipment if you can't clearly
disconnect it -- not a smart idea imo.