Arny Krueger wrote:

If you go back to the post that started this portion of the
discussion, we were talking about transients that are likely
to be generated inside the house, not lightening. Transients
from other standard electrical appliances, audio or
otherwise are the context.

Lightning transients can be generated inside the house! That is the
interesting thing about all this. You get a nearby lightning hit, and
you get stuff induced into your internal wiring.... remember this stuff
is acting like RF and your interior wiring will act as an antenna.

Stuff like motor and switching transients is pretty minor, because most
of that stuff is well below the clamp voltage anyway. Those problems
are best solved with just low-pass filtering. In industrial facilities
with big single-phase motors, arc welders, and induction heating systems,
that could be different. (But again a lot of that stuff is high enough
risetime that it acts like RF).

We've also agreed that for openers, whole-house surge
supression should be installed wherever damage from external
surges sources like lightening is an issue.

Absolutely, BUT don't think that whole-house suppression is all that
you need to protect you from this stuff.

While this subthread hasn't exactly covered the issue of
protecting structures from lightening that strikes them, (as
opposed to strikes on or near a power line) I think that
Scott you've posted some agreeable advice about that as
well.

Hire Cortana to come out and look at the building. Or ask your insurance
company to get an expert over... they will probably pick up the tab.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."