Larrybou,
What country do you live in?
What is the mains nominal voltage?
How bad does the mains voltage feeding your home fluctuate?
How high above the nominal voltage have you measured?
I would probably start at the main power electrical panel and install a good high quality SPD, Surge Protection Device.
Then down stream at your equipment install your secondary SPD protection.
Note,
A short sustained high voltage event above the limits of the SPD will fry the SPD.
Whole House Surge Protection
.
What country do you live in?
What is the mains nominal voltage?
How bad does the mains voltage feeding your home fluctuate?
How high above the nominal voltage have you measured?
I would probably start at the main power electrical panel and install a good high quality SPD, Surge Protection Device.
Then down stream at your equipment install your secondary SPD protection.
Note,
A short sustained high voltage event above the limits of the SPD will fry the SPD.
Whole House Surge Protection
.

