On Jul 18, 2:59 pm, Douglas Johnson wrote:
Please list the exact specifications you desire and an example of a protection
claim that would satisfy you.

In most cases, upgrading earthing to post 1990 National Electrical
Code provides a massive improvement - over 90% of what might be best
achieved. Earthing to a water pipe on the other side of the basement
is woefully insufficient; all but no earthing. To achieve maybe a
single digit percent improvement, massively expand an earthing
system. Another reason to enhance that earthing system is to correct
unexpected problems that might compromise the single point earth
ground (again, see that 14 Jul discussion).

Like a house foundation, earthing is the foundation of any
protection system. Any wire that might carry a surge into the
building must dump surge energy harmless into earth. If that
connection is via a protector, then we want a protector that will
earth direct lightning strikes without damage. Minimally sized 'whole
house' protectors for AC electric start at 1000 joules and 50,000
amps. Don't let those numbers also on plug-in protectors fool you. A
'whole house' protector uses all joules during protection. Plug-in
protectors do not.

Since an average surge is 20,000 amps and since that surge will also
be seeking other homes, then a 50,000 amp 'whole house' protector is
minimally sufficient. Joules is a ballpark measurement for protector
life expectancy. We expect a protector to last over ten years without
ever failing. Properly sized (effective) protectors only degrade.
Remain functional for 10+ years and do not fail catastrophically.
More joules exponentially increase a protector's life expectancy.

Whereas quality of and connection to earth ground determines a
protector's effectiveness during those critical microseconds; joules
determines whether the protector is functional for decades.