Those spikes and transients find a path to earth ground,
destructively, via your electronics. Appliances already have
effective internal protection. Protection that can be
overwhelmed IF you don't earth the incoming transient before
it enters a building.
Your incoming cable should already be connected to that
protection - if properly installed. Effective protection
without using a protector. Note the difference. Protector
and protection are two different components of a surge
protection system. Not all systems require protectors. But
all systems require the one essential component - single point
earth ground.
Cable must enter building connected less than 10 foot to a
single point earth ground. A hardwired connection; no
protector required. But a ground block is often used.
The most common source of destructive transients is from the
wire highest on utility pole, most often struck by lightning
(which is why cable and telephone wires are rarely struck),
AND a direct connection to all household electronics. This
wire often has no effective connection to earth ground AND
requires a 'whole house' protector. Protector that costs
typically $1 per protected appliance (compared to how many
tens of dollars for overpriced and ineffective plug-in
protectors). One example is sold in Home Depot as Intermatic
IG1240RC. Others are listed in a previous discussion in
newsgroup misc.rural:
"telephone wire/lightning strikes" on 30 Sept 2003 at
http://tinyurl.com/q6g6
Principles for protection are summarized in a recent
discussion in this newsgroup sci.electronics.repair entitled
"Repairing Lightning Damaged Tv's" starting about 15 Jun 2004.
If you think a protector on the coax is protection, then you
have much to learn from that previous discussion. One even
recommended an APC product that does not even claim to provide
the protection he has assumed. The plug-in UPS simply
connects TV directly to AC mains when not in battery backup
mode. Where is the protection? Does he think a silly little
component in the APC is going to stop what miles of
non-conductive air could not? Those UPS recommendations for
protection are based on wild assumptions. It claims to
protect from one type of transient. Therefore it will protect
from all type of transients? No, it does not even claim to
protect from the type of transient that typically does
damage. That plug-in manufacturer simply says only enough for
posters to *assume* it protects from all type of transients.
No earth ground means no effective protection - which is why
that APC manufacturer avoids all mention of earthing - so that
myth will be posted as a recommendation.
Even series mode protector manufacturers forget about a wire
that completely bypasses the protector; can carry a surge
directly into electronics. Again, is that silly little
protector going to stop what miles of air could not?
Posted above is what was proven by research papers long
before WWII. Plug-in protectors simply violate those well
proven principles; and then avoid mentioning well proven
concepts. A protectors is only as effective as its earth
ground. How one identifies ineffective protectors: 1) no
dedicated connection to earth ground and 2) avoids all mention
of earthing - the most critical component in every protection
system.
