On Tuesday, October 20, 2015 at 10:42:49 AM UTC-4, trader_4 wrote:
Oh no, here we go again. It's been pointed out to you 100 times over
the years that while a lightning strike can be 20,000 amps, the chances
of that showing up at the panel are virtually nil.

Here we go again. Trying to explain well proven concepts to someone who only wants to argue. For the benefits of others, Dr Martzloff's late 1970s IEEE paper contradicted this naysayer. He ignores Martzloff's numbers. This naysayer invents denials to be nasty.

Dr Martzloff describes a 100,000 amp lightning strike to AC utility wires. 40,000 amps gets earthed by the 'primary' surge protection layer (earth ground on the pole). 20,000 amps goes off to other homes. And 40,000 amps is incoming to this home's panel. 40,000 amps must be earthed by the 'secondary' protection layer - a properly earthed 'whole house' protector. No problem when properly sized - at least 50,000 amps.

Chances of a 40,000 amp surge are rare. A destructive surge typically occurs maybe once every seven years. And because most lightning strikes are less than 100,000 amps.

But a 20,000 amp surge is possible. Other surge sources (ie 33,000 volt wire falling on local distribution) are also why we earth that 'whole house' protector. A friend witnessed it. Others without properly earth protection had major appliance damage. At least one had multiple destroyed circuit breakers. Many electric meters literally exploded up to 30 feet from their pans.

My friend knew someone who knows about surge protection. His meter also exploded. But, unlike others, he had no appliance damage. Even his properly size 'whole house' protector remained functional.

A minimal 'whole house' protector is 50,000 amps. So that lightning and other destructive surges do not damage anything - even the protector. IEEE papers and decades of experience both contradict a nasty naysayer.