You will have read of the area in Linden whose electrical equipment and house wiring was destroyed by the Council.
The main DB in the area was damaged, so they connected up a temporary generator to power the suburb.
Trouble was, they turned it on producing 380v instead of 220v - household goods, and even house wiring and DB Boards were destroyed.
They say householders must claim against the Council - apparently it takes 4 - 6 months to get paid out (being optimistic).
In the meantim, at their own cost, they must have houses rewired, and all contents - TVs, fridges, microwaves etc. replaced. Out of their own cost...
There has been so many complaints and reports in the Press that Insurance does not cover surge.
It can be covered.
Some Insurers - most of my domestic covers are with them, cover it as standard.
Other wise, you can (generally) ask for Accidental Damage extension - and most Insurers will provide that. It will brink in the Surge cover.
But, it is the old story. People buy cheap - then just discover AFTER the loss where the cover flaws are....