[Boatanchors] Storm Damage to Electronics

[Jim Haynes]

Well normally you have 115V loads connected between one side of the
line and neutral, and that applies to both sides of the line.  The
pole transformer is center-tapped with the center tap going to the
neutral, so you may be drawing more current on one of the sides than
the other but the voltage stays correct on both sides.

Now when the neutral is broken. you still have 230V between the
two sides, but the neutral is floating.  So if there are low impedance
loads on one side that will pull the side-to-neutral voltage low
on that side and consequently the side-to-neutral voltage on the other
side goes high.

Something similar happened to me in California, except nothing was
damaged.  In the redwoods country of California there are lots of
outages caused by falling limbs when the first storm of winter hits.
Now the neutral wire also serves as the support strand for the other
two insulated wires.  In this case the neutral was held by a cable
grip anchored to the house, and the neutral wire going into the house
was attached to the cable grip rather than to the neutral wire from
the pole.  All was well so long as the cable grip holds.  But when
the drop wire was hit by a falling limb it pulled the neutral wire
out of the cable grip, and hence the neutral was no longer connected
to the house.  There were lots of other downed wires in the area,
so all the power was off until the power company got them fixed.
Then when power did come back on there was my floating neutral and
bright lights on one side and dim lights on the other side.  I realized
what had happened, turned off the power, then used a car jumper cable to
reconnect the neutral to the grip, and turned things back on.  And all
was well and lasted until the power company came by my house and
fixed the neutral.

And I told them it was very bad the way the thing had been installed,
and insisted that they not use the grip as the way to connect the
neutral to the house, but connect the neutral conductor separately
to the house neutral.