Protection is always possible. Ham radio operators in the
early 1900s would suffer damage. They disconnected the
antenna. Still suffered damage. They placed antenna lead
into a mason jar. Still suffered damage. They earthing the
incoming antenna wire. Damage stopped happening.

Damage occurs whenever the direct strike finds a path to
earth ground inside building via the appliance. Incoming on
antenna wire. Outgoing via speaker wires to earth ground via
concrete floor or by being draped on adjacent baseboard heat.
Your situation may vary.

But this we have always understood. Protection works when
all incoming wires are earthed to a single point ground. That
means all utility wires must enter building at same location.
That means the single point earth ground must be the best
earthing for that building.

Your phone already makes that earthing connection using a
'whole house' protector inside the premise interface box.
Phone cannot work if earthed directly. So a protector makes
the temporary earthing connection; earthing wire only during a
surge. Your cable needs no protector. But cable needs
connection to protection. Cable connects directly to the
single point earth ground before entering building to earth
incoming transients.

Earthing is why effective protection works. The single
point earth ground. And yet 30 years after the transistor is
ubiquitous, we still don't build new buildings as if the
transistor exists.

AC electric routinely enters without connection to earth
ground. Again, this utility requires a 'whole house'
protector such as from Home Depot (Intermatic IG1240RC). And
- of course - your building's single point earth ground may
not yet exist. Older buildings often had no single point
ground. The building owner may need to upgrade or exceed
earthing requirements of the current National Electrical Code.

No earth ground means no effective protection. The naive
assume nothing can protect from lightning even though it is
done annually in virtually every town. Remember the lessons
from early ham radio operators. Earthing is still necessary
to avoid damage. Protection is only as effective as its earth
ground.

Sunny wrote:
w_tom wrote:
...
Protectors are effective when they make the 'less than 10
foot' connection to earth ground. Called 'whole house' type
protectors. That is what a utility installed protector does
IF your building has been wired to post 1990 code requirements
for earthing. A utility typically does not even check that
your earthing exists. Household earthing being the
homeowner's responsibility; not utilities. No earth ground
means no effective protection even from that utility provided
protector that typically costs a very expensive $5 per month.
...
Bottom line: a protector is only as effective as its earth
ground. Something that plug-in protectors fear you might
learn and avoid mentioning.


Unplugging is unreliable even when the human is available and
paying attention. I recently lost an expensive stereo and TV due
to a direct hit about 20 feet from my cottage. The equipment was
unplugged prior to the strike, but I didn't think to disconnect
the speaker cables and antenna...

An extension cord lying disconnected on the ground outside
writhed like a snake and now has neat holes burnt through the
outer casing at exactly 27" intervals.

I doubt protection is possible under those circumstances - but I
did catch 3 nice sized Northern Pike for dinner with my bare
hands as they floated past the dock, stunned :-)