westom
Thu, 09
Feb 2017 14:53:02 GMT in alt.home.repair, wrote:

My friend knows someone who knows this stuff. So he had a 'whole
house' protector. His electric meter was also damaged. But
nothing else. Even the 'whole house' protector was not damaged.
In part, because it was properly earthed.

In part? Er, no. That's the primary reason the protector and
everything else wasn't damaged/destroyed. Your house protector does
the same thing the plugin surge protectors do on a larger level. It
tries to redirect excess current on either/both legs to ground, to
bleed it off as quickly as is possible.

Transients created by lightning, linemen errors, tree rodents,
stray cars, and insulator failures are rare. So we properly earth
a 'whole house' solution for about $1 per protected appliance.
Then such threats do not cause hardware damage - even to that
'whole house' protector.

As long as the ground is good. If the ground is damaged for some
reason as part of the massive overcurrent issue, the protection
devices have nothing to work with, whatever they can't surpress with
their own electronics on board is going to travel throughout the
house. Some surge supressors will attempt to bleed into the neutral
lines as well, but, as I said, if those lines are damaged, it has
nowhere to bleed off that excess current. It's electronics will
sacrifice themselves trying to stop the surge, but, if the surge is
strong enough and of a sufficient duration, the protective device
will give up everything it's got and sadly, some current is still
getting past it.






--
Sarcasm, because beating the living **** out of deserving people is
illegal.