My thoughts:
a] For mains protection, forget about MOV's, they can only take a handful of hits, and they age quickly. Gas-tubes, TVS are superior and only found in better power bars etc. Or an huge LC filter works well.
That handful of hits number is 3 million!
B] If many homes in your neighborhood have those power company provided surge protectors, they sort of work together in parallel to absorb common surges.
c] The series mode surge protectors from:
Brick Wall
ZeroSurge
SurgeX
Are all excellent point of use surge protectors, but they are all very expensive!
d] Other types of point of use surge protectors all have their pluses and minuses.
But a modern home has many point of use surge protectors, so the minus that remains is that they dump noise onto the Safety Ground/Protective Earth.
a] For mains protection, forget about MOV's, they can only take a handful of hits, and they age quickly. Gas-tubes, TVS are superior and only found in better power bars etc. Or an huge LC filter works well.
That handful of hits number is 3 million!
B] If many homes in your neighborhood have those power company provided surge protectors, they sort of work together in parallel to absorb common surges.
c] The series mode surge protectors from:
Brick Wall
ZeroSurge
SurgeX
Are all excellent point of use surge protectors, but they are all very expensive!
d] Other types of point of use surge protectors all have their pluses and minuses.
But a modern home has many point of use surge protectors, so the minus that remains is that they dump noise onto the Safety Ground/Protective Earth.
Point of use protection that is effective is already inside every appliance. Meanwhile Dr Martzloff made it quite clear in his IEEE papers that "point of connection" (point of use) protectors can even make damage easier. They do not claim to protect from the type of surge that typically does damage. Those above recommendation come without any reason to believe them - and without spec numbers.
A number makes obvious weakness in those series mode (Brickwall, et al) protectors. How many joules does it claim to absorb? Destructive surges can be hundreds of thousands of joules. Doing some math using their spec numbers suggests it can only absorb 6000 joules. What happens during a destructive surge? That current blows through the series mode filter. And blows through more robust filters that are already inside electronics.
Why spend so much on a series mode filter that does less than what is standard inside electronics? Advertising. And that above recommendation also ignores numbers.
Even fuses have numbers. Numbers must be in every recommendation. A surge is done typically in microseconds. Fuses take milliseconds or longer to blow. 300 consecutive surges could exist before the fuse even thought about blowing.
Then a fuse also has a voltage number. For example a 250 volt fuse will continue conducting is voltage exceeds 250. What does a destructive surge do when something tries to stop it? Increases voltage as necessary so that current continues to flow. Any fuse that blows to block a surge simply keeps conducting that surge until the surge decides to stop.
Fuses do nothing for surge protection. Fuses avert a fire AFTER damage has occurred.
Best 'whole house' protectors use MOVs. Yes MOVs degrade. And again, nobody cares once one stops ignoring specification numbers. A direct lightning strike may be 20,000 amps. So a minimal 'whole house' protector is 50,000 amps. So that the protector remains functional after many direct strikes over the many decades. Concern for MOVs degrading only exists when one is using near zero plug-in protectors.
Again, the question that must be answered in every post that makes a recommendation. Where do hundreds of thousands of joules harmlessly dissipate. More recommendations were posted by ignoring that simple and essential question.
BTW, we have been discussing the 'secondary' protection layer. All homeowners should also inspect their 'primary' protection layer. That primary protection layer means even less of a direct strike tries to enter a house destructively. Once inside, then nothing inside can avert that destructive hunt - especially not adjacent (point of connection) protectors.
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The very high frequencies might try to dump the spikes into the high impedance return route to the distribution board, but the capacitive coupling between the enclosing chassis and the EARTH is a lower VHF impedance and most of the VHF (into the GHz range) bypasses the copper route.
This is my interpretation of H.Ott.
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