On Monday, October 19, 2015 at 9:27:38 AM UTC-4, westom wrote:
On Sunday, October 18, 2015 at 9:07:06 PM UTC-4, Uncle Monster wrote:
Lightning strikes would often blow the hell out of the surge arrestors
but none of the very expensive equipment was ever damaged.

Obviously did not happen that way if one remembers how electricity works. If a current is incoming to an adjacent protector, then at the same time a current is outgoing into attached expensive equipment. Where is the protection?

A protector, blown to hell, has not provided protection. A surge is a current source. That means voltage increases as necessary to 'blow to hell' anything that tries to stop it. Voltage increased as necessary (causing catastrophic protector failure) so that current also flows into attached equipment. Both incoming and outgoing current paths must exist simultaneously. Where is the protection?

Poor Tom, confused again. In the described situation, the current has
at least two paths, through the equipment or through the surge protector
to ground. All the current clearly does not have to go through the
protected equipment. Even with a failed, blown, surge protector, a lot
of the current almost certainly went through the surge protector to
ground.



A surge current, too tiny to damage attached (more robust) equipment, also destroyed a grossly undersized protector. Where is protection?

Totally made up. Who says that the surge was too tiny to damage
the "more robust" eqpt? The surge protector almost certainly
directed most of the surge current to ground. And I've yet to see
an external surge protector that has components that are rated lower
than those in the typical home appliances, eqpt, etc. They use the
same type of components, but the ones in the external surge protector
almost always have much higher capacities.




Adjacent protectors are for tiny and completely different transients already made irrelevant by protection inside equipment. Adjacent protectors do not claim to protect from a typically destructive surge - that hunts for earth ground - that typically does damage.


Baloney. The IEEE guide to surge protection which has been provided
to you many times, says you're wrong. They show point-of-use protectors
used as part of a tiered protection strategy. Here is the link:

http://www.lightningsafety.com/nlsi_lhm/IEEE_Guide.pdf




Third, an IEEE brochure Figure 8 demonstrates same. A home had no properly earthed 'whole house' solution - no 'secondary' protection layer. So a plug-in protector earthed a surge current 8000 volts destructively via some nearby TV. It did what a protector does IF not properly earthed. To even make damage easier.


That isn't what that guide shows at all. It clearly shows in that diagram
TV1 that has a plug-in protector being protected, while the other TV, TV2 with
no protector gets damaged. Only a true loon would try to turn
that into the surge protector at TV1 *causing* the damage at TV2.

http://www.lightningsafety.com/nlsi_lhm/IEEE_Guide.pdf

Page 33. It ends with "to protect TV2 a second surge protector is required".

QED


Fourth, if a protector was blown to hell, then it was a potential fire. Fire has always been a problem with undersized (plug-in) protectors - that are blown to hell. Protector part (MOV) manufacturers are blunt. That 'catastrophic' failure is unacceptable. APC recently announced some APC protectors are so dangerous as to be removed immediately.


Show us that "recent" APC recall please. AFAIK it was over a decade
ago. GM recalled some cars, does that mean all cars are unsafe?