On Sep 30, 10:46*am, w_tom wrote:
On Sep 29, 5:40 pm, N8N wrote:

* Those "couplesurgestrips" did what no protector must do - failed.
I "fail" to see how that is bad - apparently an overvoltage got
through my whole house protector (according to the power company, in
their nice "GFY" form letter, a high voltage line was knocked into a
low voltage one by a falling tree, neatly bypassing the transformer,
so it must have been a big jolt) and the surge strips shut themselves
down rather than pass through the overvoltage to the equipment
connected to them.

* *A surge does not enter the home like a wave on the ocean.
Electricity does not work that way. *A surge first flowed through
*anything* in that path to earth. *Long after that surge is flowing,
then something fails.

My understanding is that there are generally three MOVs in a typical
AC-only surge protector, H-N, N-G, H-G. If any of those MOVs fail
they generally fail shorted rather than open, directly either shorting
a current-carrying conductor to ground or else shorting hot to
neutral. This causes an internal fuse or circuit breaker to open,
completely disconnecting the load from the line. Thus this *does*
protect the load from a surge, unless the overvoltage is such that it
can actually cross the gap in the fuse/breaker.

Or am I missing something?

nate