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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
britamerican
52 posts
 

I was only half joking when I wrote "safety be damned".

I would say the same thing about the person who wrote this. They either don't know what they are doing or are lying.  I get the impression the UberBUSS is like the BlueCircle and TLP products. Stack as much capacitance across the line as possible, safety be damned!

Then I came across this for a different product that has their PFC function on whatsbestforum.


 

erik_squires OP
16,134 posts
 

I get the impression the UberBUSS is like the BlueCircle and TLP products. Stack as much capacitance across the line as possible, safety be damned!

 

@britamerican Isn’t there an NEC or UL limit to the amount of capacitance you can put on the AC line, before any primary windings??

vinylshadow
497 posts
 

@erik_squires Why thank you. Thank you very much. 

britamerican
52 posts
 

@britamerican Isn’t there an NEC or UL limit to the amount of capacitance you can put on the AC line, before any primary windings??

If you asked me that 15-20 years ago maybe I would have known the answer. I doubt UL or NEC would ever say the capacitor can only be this big. They will write a bunch of paragraphs that will have the same effect. 5 minutes on Google and I found maximum of 34V after 1 second.

nagel
56 posts
 

Caelin Gabriel and Shunyata make suppressors for medical gear so I think they're a lot more knowledgeable than most people here. I spoke with Tim from Transient Protection Design who said that their whole home unit has MOVs that turn on at 150v. I encouraged him to have his engineer write something more detailed that I could share. They also recommend a defense on depth approach for sensitive electronics, and have detailed pdf showing how a home filled with electronics might be protected.

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