On Tue, 23 May 2017 10:52:32 -0700 (PDT), trader_4
wrote:

Still unanswered after all these years, if a direct, nearby, earth ground
is essential, then how do those MOVs inside appliances work? At times
you've held positions ranging from they work and that's why appliance
manufacturers put them in, to at other times denying that they use MOVs
at all.

Before I did my inspector gig I was a hardware guy at IBM in Florida.
Lightning was our biggest single cause of failure until we learned a
bit about surge protection. A lot of the knowledge out there came from
central and SW Florida.
The first thing is most electronic damage is not coming from that
"finger of god" lightning strike right next to you. It comes from the
difference of potential between different machines. The classic is the
telco/modem and the PoCo/PC. That is what your primary surge
protection should deal with If you catch it at the service entrance,
all the better but you need all protectors tied to the same ground
electrode.
You can also have smaller surges generated on the load side of the
service. This is why you use point of use protection. We also went as
far as running bonding wires between machines that were separated by
some distance making them as direct as possible and then looping the
data lines to make them longer., You can lake them look linger than
that with ferrites. The idea is your ground and your point of use
protector can stop the surge before it gets there.
I won't even try to make the case theoretically. I just know the
results. We went from 1000 lightning calls a year in my 3 county area
to about 2.