I have a, "whole house" surge protector! I suspect it died trying to protect my circuit board.

Have you checked that out? Did it actually die, or is it in another hard to reach place and you haven't had the time to do it?

 

It's on the side of the circuit breaker box, which requires two screws and a 1/2" electrical nut to take it off right now. It has a fake, "OK" indicator which says it's still OK. I am not sure how to test a giant MOV. You just read about how much fun it was to spend a day up a ladder and 2 days being sore. Besides that, I have to help my family with their hurricane problems. Today seems like a good day to mow the lawn because the heat index is going down early! Below 90F at 7 pm.

I haven't mowed since before the hurricane, so I'll do that before I design a way to test a giant MOV.

 

It has a fake, "OK" indicator which says it's still OK.

How do you know it's fake?

 

How do you know it's fake?

Because a MOV suffers no damage at all if it doesn't suppress any voltage surges. Therefore, its lifetime is infinite in an electrically quiet environment. Meanwhile, you CAN calculate a Mean Time Between Failure for the LED which says the MOV is OK. You tell me how to put an, "OK" timer on, "infinite" and I'll quit calling it, "fake".

 

Some difficult to describe over-voltage arrived some 10 hours after the hurricane was over and power restored (about 7 days later).

Thus it seems a shipping line crossed a distribution line/secondary network - the impedance differential -saving grace though it is- is seldom 'all things to all subscribers' in such instances (as you have seen)

All was encased in proper metal enclosure, so I have to say, arc-flash. Fairly amazing to me to see a hole that looks like a plasma torch went through the PC board.

Good job it didn't breach the enclosure and set fire to the building! -- Oh yes! It happens!

And I have a, "whole house" surge protector! I suspect it died trying to protect my circuit board.

Assuming my (above stated) 'hypothesis' is correct - Any expectation of damage mitigation from that quarter would be as expecting to arrest the motion of 109P with a catcher's mitt

Definitely off topic.

I wasn't complaining -- Merely indulging in a bit of drollery

Very best regards
HP

 

Good job it didn't breach the enclosure and set fire to the building! -- Oh yes! It happens!

I had assumed that a full metal enclosure per NEC was sufficient, but I also know of a house that suddenly blew its roof off. Completely unexplained, even after the fire inspectors tried to figure out what the source of ignition was.

I think a long smouldering fire found a source of oxygen, but the cause of smouldering is still unexplained.
(The occupants escaped, but they smelled like the gates of Hell!)