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Why whole house surge protectors are not enough

TL;DR:

One measure of a surge protector is the clamping voltage. That is, at what voltage does the surge protector actually start to work. Whole house surge protectors are limited to no less than ~ 600 Volts (instantaneous) between a leg and neutral or ground. That’s up to 1,200V if symmetrical.

The best surge protecting strips and conditioners clamp below 200 Volts.

Please keep this in mind when deciding whether or not to use surge protectors at your PC, stereo, TV, etc. in addition to a whole house unit.

I wrote more about this here:

 

https://inatinear.blogspot.com/2021/09/time-for-new-surge-suppression.html

No manufacturer of whole house surge protection claims that their devices alone are enough for sensitive electronics when you check the fine print.

erik_squires

Showing 4 responses by terry9

terry9
2,229 posts
 

Just to lower the tone for a moment, I did a trip around the house and found that two of my surge suppressors were no longer suppressing anything. One replaced, one on order. Goes to show - some attention required.

terry9
2,229 posts
 

I use isolation transformers for all my audio gear, and all the A/V. Maybe that's why my 2009 Kuro Plasma is still working - and working well enough to make the 4K upgrade unattractive.

terry9
2,229 posts
 

And thanks for the thread, Eric. A real public service.

terry9
2,229 posts
 

From an important textbook:

"... it is not possible to turn off the current (to an inductor) suddenly, because that would imply an infinite voltage across the inductor’s terminals. What happens is that the voltage rises abruptly and keeps rising until it forces current to flow. ... in a case like this ... (20 VDC supply) it may go to 1000 V before the switch contact "blows over". "

"Art of Electronics 3rd Edition", Horowitz and Hill, page 38.

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