Last Saturday afternoon we had a severe storm in southern Indiana
with winds in excess of 70 mph which caused an electrical service
outage and damage to over 5,000 customers.
The electrician who repaired my damage informed me of a
situation I was totally unaware of, so if any of you who have
a residential electrical service background could give me
some insight it would be greatly appreciated.
So, here's what happened:
The wind gusts resulted in service loss and left my service pole
and the adjacent pole, with a transformer, arcing and producing
a very noticeable high voltage hum. A few hours later the utility
company cut the power; it was off about 10 hours. When the power
was restored I was in the kitchen and was startled by a booming pop
coming from my power panel which is located in an adjacent
utility room, then my microwave oven popped and had an arc flash.
I could smell electrical smoke! I heard another pop from somewhere
else in the house and then the service went dead. I retrieved my
flashlight and checked the power panel to find all the breakers
had tripped. I went outside to check the service connection to find
the meter riser and weather head had been bent toward the service
pole at about a 20 degree angle. I immediately shut off the power
via the meter/service switch and called an electrician. A day and a
half later when the electrician arrived he discovered that, in addition
to the obvious damage to the weather head, the ground cable in the
overhead service line had been sheared (broken).
The electrician informed me that there was a 90% chance that all of
the electronic devices in the house were fried! Thinking about my
Carver gear I was panicked!!! He said that because there was no ground
when the utility company powered the service back on there could also
be damage to other major appliances as well, but that most certainly
the electronics were destroyed.
After he repaired the meter housing, riser, weather head, ground cable and
restored the electrical service I was very relieved to find the Carver gear
was not damaged. The only damage was to the microwave, coffeemaker
and the AT&T modem for my desktop computer. He theorized that because
I had shut off the power that I had avoided further damage. What dumb luck!
Has anyone encountered this situation?
Is it true that a broken ground cable can cause the above mentioned damage?
If so, is there a method/device to prevent that kind of damage?
Please help me to understand this occurrence.