Ben Franklin demonstrated the concept in 1752. Lightning
traveled miles through non-conductive air to obtain earth
ground. Is some silly opto-isolator or point of use surge
protector going to stop, block, or absorb lightning? Of
course not. But effective protection has been demonstrated
repeatedly since before WWII. Effective protection does what
Franklin did in 1752.
Lightning seeks earth ground. Divert lightning to earth
before it can strike the church steeple. Well proven by
centuries of experience.
Electronics has the same problem. If lightning finds a
circuit path to earth via household electronics, then surge
damage result. Again well proven is to earth the surge, at
service entrance, before surge can enter a building.
It's called 'whole house' surge protectors. But surge
protectors are not surge protection. A surge protector is
only as effective as its connection to surge protection -
earth ground. No short connection to earth ground (which is
the problem with plug-in or point of use surge protectors)
means no effective connection.
A surge protector is only as effective as its earth ground.
Surge protectors are simple science - often hyped into myth.
The art of protection is earthing - not a surge protector.
Which again demonstrates why 'point of use' protectors are so
ineffective. Since they don't provide effective protection,
then there is no dedicated (less than 10 foot) connection to
earth AND those ineffective protectors avoid all discussion
about earthing.
Just as Franklin demonstrated. Surge protection is about
earthing a surge. That is what a surge protectors does.
Connect all wires to earth ground only during the surge (which
is why a surge protector must have a less than 10 foot
connection to earth).
The most common source of destructive surges (even to
modems) is AC electric. Surge enters on the one utility that
typically has no protection. Telephone line has and CATV
should have 'whole house' protection. But AC electric - the
utility highest on pole and most struck - makes a direct
hardwire connection even to modem ICs.
What does a surge seek? Earth ground. Any appliance that
makes a connection from AC electric to earth ground becomes a
complete surge circuit. Modems and portable phone base
stations are easily destroyed. Incoming on AC electric.
Outgoing to earth ground on phone line (because telco already
installs 'whole house' protector on phone line).
Two minimally sized 'whole house' protectors are sold in
Home Depot - Intermatic EG240RC or IG1240RC, and Siemens
QSA2020. Never seen any effective surge protectors sold in
Sears, Walmart, Lowes, Kmart, Staples, or Office Max.
Obviously. They don't have a dedicated connection to earth
ground AND avoid all earthing discussions. They don't even
claim to protect from the typically destructive type of surge.
Just a few introductory concept about protection. Will not
even discuss so many erroneous facts posted in the
www.penlight.org FAQ. Discussion for another post. But this
is the fundamental fact. A surge protector is only as
effective as its earth ground. Surge protectors don't stop,
block, or absorb surges. They only shunt - connect all wires
together - during the surge. That shunting is protection only
if connected less than 10 feet to earth ground.