POCO Surge

I haven’t dealt with any big enough to melt buss bars, but I had a situation where an enormous fir fell across the distribution lines, causing a phase to phase fault.

There are SPDs at the service panels at this one place, and one in every sub panel. One house on the property has two subs. One with a breaker style SPD, one with an exterior panel mount SPD.

The one with the breaker style SPD blew the door of the panel open, dislodged the SPD, and knocked 2 adjacent breakers off the buss.

The panel mount SPD cracked open and some kind of sand that is inside was spilling out.

SPDs at the main service were black.

POU SPD on the washer and dryer fried, and the washer electronics burned up. Dryer was fine.

All told I replaced 6 SPDs. PG&E paid for all the devices, and the new washer. Wouldn’t pay my service call though. 😳
 
Closest I have seen to this is when a higher voltage line somehow contacts a lower voltage line.

Can't say I've seen it melt bus bars but definitely blown fuses, breakers and damaged electronics most the times I followed up after such an event.

The usual surges from load switching and such don't do this.

Nearby town had a transmission line supplying the town substation fall on a secondary distribution line.

All power was off afterwards until POCO cleared the issue. There were several service calls after though. I noticed they tended to be in clusters, like several calls from one block in the town, and then another cluster of all in a different block - presuming those were all on the same primary phase that the fallen transmission line was involved with? Remember replacing nearly every GFCI in the house in many of those places, and some fried computers or maybe fried oven controls and such. This was before AFCI was being installed here or may have been some of those as well.
 
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