Hi Luminus+Tim,

Lowered probe impedance at higher frequencies had not occurred to me, thank you Tim for pointing that out. I think it’s difficult to know exactly what happened in this case, especially remotely, so I don’t want to speculate too much. Luminus if you get more information please let me know. The meters were tested to withstand 4000VAC surges, but I think those tests were only 1-second long exposures (meant to simulate a lightening strike outside the house while touching mains inside).

Best
~James