I was called to residence yesterday to do an inspection of damage for the insurance company. We recently had an ice storm that took down power lines. This customer was out for 4 days. When his power came back on, he had multiple items burnt up. Micro, stove, cordless phone, dishwasher, tv, vcr, dvd player, computer surge protector, flourescent lights to name a few. The major items didn't get affected because he had them unplugged and plugged into a generator.
The odd thing about this is everthing affected was on the same phase in his (120/240) panel. Now I have seen this before on a phase to neutral short on an overhead service. But his service is all underground from the transformer pole to his house. The cause of the outage was a primary line broke a mile down the road.
The only thing I can think of that wasn't covered would be a loose neutral. Many of the items you mentioned are electronic or contain electronics . Electronics don't much care for high voltage. Did you take any voltage measurements while you were on site?
Few things are harder to put up with than the annoyance of a good example.
Did the primary break and drop onto the one line feeding into the house? Maybe it dropped onto the line at someone else's house and backfed his house.
No that was not possible. The primary that broke was a mile down the road. And no I don't believe that it could have back feed because this is the only house on this transformer. The transformer pole is only 45' from his house. The secondary comes down the transformeer pole underground to his house.
If there were no wires down in that entire mile from the primary down to his house, that primary down will be the biggest suspect culprit. Still, it is hard to imagine it causing the surge to extend to your customer's house unless there were secondaries run the whole way (which you say is not the case).
Any overvoltage on the primary would have affected both 120 phases and everything 240. If all the damage is on one 120 phase, that sounds to me more like an arc-over in the transformer, or a fault of the other phase to neutral somewhere.
I suggest a test. Find another surge protector exactly like the one that failed. Apply 240 volts to it and see if it fails. Some will and some won't. If it does not fail, then there had to be more than 240 volts.
A closer inspection of damage to appliances might give a better idea of what the voltage involved was. Any change it might have been an UNDERvoltage issue?
Did the homeowner report any lightning events? I have experienced lightning in snow and ice storms before (but luckily was not hit by it).
My first thought when I got the phone call was an undervoltage. This seems to happen frequently in these type of storms. However upon inspection, it is all on the same phase and shows sign of an extensive surge. The next scenario is lightning. There were some thunderstorms reported in the area, however I never saw any. That is the only case that I can see but the homowner says that he didn't see any.
My next step is to talk to PoCo and have them check the transformer and connections. I am also going to recheck all secondary connections for loose neutrals, ect.
Question: Is the wire that came down the same phase as the one supplying the transformer?? If they are different phases, and the transformer primary is connected line-neutral, and say the neutral has a poor connection in it somewhere or is undersized, would it not be possible the transformer saw a momentary overvoltage if the downed wire contacted the primary neutral or the fault current tried to return through the primary neutral?? For a brief time that transformer primary would have a voltage across it somewhere between the line-neutral and line-line voltages, at least until the primary fuses opened up would it not??? I would think that would cause enough of a voltage rise in the secondary to burn things up..
I would consider everything you stated as "major items". Sorry I have no decent idea as to what might have happened. Make something up (blame POCO)and be done with it.
So, you have no real idea as to what might have occured, but you are willing for this guys customer to lie to the PoCo. That is called Fraud.
Why is it always the PoCo's problem? Home-owners should have their own Surge Diversion equipment, installed in THEIR panels if they have sensitive gear that might be cooked by voltage surges. I'm all for personal responsibility.