The power surge from the electrical line has taken out electrical appliances from many houses not sure if it's a power sub station fault or primary lightning strike on power pole.
But some of the houses had SDP installed indeed on their main distribution panel. but nonetheless electronic appliances has been impacted like TV , AC main circuit board are all fried.
One of the house owners told me that the SDP that they installed caused frequent tripping and it didn't serve them any good and they have lost appliances due to voltage surge anyways.
A Month back, I got to know there was a lightning strike on a tree and that caused some kind of secondary lightning effects i.e induced power surge in the residential electrical line or ground potential rise and somehow the power voltage surge entered into the building through ground rod or something because their plumbing lines are plastic and the earth rod is the only thing that's buried in earth and have connection to building electrical line and again this house also had SDP category 1 and 2 installed in their building.
So I enquired the electrician from power station , he told me that SDP is just a fancy thing that rich people have in their home and it never works and it's just a nuisance with constant tripping.
I don't know how much I can take this professional's word , may be they bought a good for nothing SDP or the person who installed the SDP didn't wire it as it should be.
So why does an SDP not work correctly?