A related update:
In the process of adding battery backup to the house. It is a process. In our case, a very long drawn out process because the battery supplier hasn't supplied very many batteries last year or this year. As in we ordered the batteries spring 2020.
Well good things come to those who wait, or so I have been told. Batteries finally arrive at the electricians.
First the main panel has to be replaced with one that has upgraded 225A busbars. Get the power company out to cut the overhead wires. Literally. The lineman crawls on the roof and cuts the cables, wraps them in electrical tape and leaves. Cut the old panel out of the side of the house, pull the old service drop (4/0Al!), install new service drop (copper), install new panel, reinstall existing circuits. Wait for the lineman to come back. He does, and splices the old overhead wires into the new service drop and leaves. House back on six hours later. Everything works.
Then install the batteries, automatic transfer switch for the batteries, move the solar connections to the automatic transfer switch, add a panel to take all of the circuits to be backed up by the batteries, all without turning off the house power. Three days, lots and lots of wiring, and large conduits.
Now comes the fun bit; you have to turn off the house power to move the house circuits out of the new (3 day old) panel, into a newly installed backup panel, and install a 200A breaker in the main service panel to feed the automatic transfer switch and backup panel. Following this? Yes, the wiring gets convoluted, but all according to NEC rules.
After moving the wires, turn the main service disconnect on.
Nothing happens. No power. The smart meter is blank. I figure that a fuse blew on the power pole.
Ok, I will call the power company, but first I get out the extension cords generator and get the essentials on power. While doing that I notice a surge strip with a green LED on. WTH? I go back to the main panel, and measure 16V on one phase. Throw the service disconnect off. The smart meter now comes on as far as reading out idiot lights "88888". Ok, call the power company, figuring the fuse blew on the power pole.
The lineman turns up promptly, he is the same guy who spliced in the new service drop on day one, so he knows what is going on. After poking around, he heads out to check main line fuses farther away, as those have easy access. Ninety minutes later, he comes back; "you need to have your transformers replaced. The crew will be out later tonight, or tomorrow morning."
Not too surprisingly, the crew comes out the next morning, and proceed to drive two large bucket trucks up and across slopes that my slope tractor has challenges with. Thirty degree slopes. They can't get their biggest truck up there, so they have to rig a pulley and winch to lower the old transformers off, and the new ones up. After a couple of hours and quite a bit of work for everyone on the six man crew, it is done. They mention in passing that they had to replace the ground wire for the pole. I am not surprised.(More on that in a moment.) Two years ago, the power company contractors worked on the pole adding rot preventative, and checking the ground, which I happened to see. So I know it was good then.
Moving on. Now, we get to experience the bad news. Flipping the service disconnect works, but then flipping on the main breaker that feeds everything fails. As in "BANG", with lots loud humming and arcing noises, fails.
As all of this happened while the panels were being rewired, the suspicion is on the rewiring, although it is hard to see how. Time to get the rewiring crew back out.
They pull the panels, and start tracing the wiring. Long, long story short, it turns out that there are two tiny teeth (less than 1/8") on the underside of a terminal for a 4/0 main busbar terminal for the neutral wire from the main panel to the automatic transfer switch. One of the two teeth is bent/missing, which has the effect of not completing the neutral circuit, resulting in a floating ground, blowing the breaker.
Whether the increased neutral flow pushed the transformers over the edge, I don't know.
Here is why I wasn't surprised to have a melted ground wire on our transformers: We had a doozy of a lightning storm a year ago, the one that started last summer's fires here in California. Eleven thousand lightning strikes or so. Since then, the power company has been replacing transformers along miles of power lines toward our place. They were due to replace ours the day before this happened, but they canceled at the last minute, so I suspect that they knew the transformers were dying.
Which leads me to wonder if
@EddieWalker has had his grounds/power lines repaired.
Stay safe out there.
All the best,
Peter