To promote inferior and profitable products, some
manufacturers will hype a protector as if it were protection.
John has defined the protection. A protector is nothing more
than a 'wire like' device that connects to protection. The
protector (or wire) is only as effective as the protection it
connects to.
The protection is earth ground - which is why better
protection means enhancing the earthing - as John has
demonstrated. A protector is simply a temporary wire
connection to earth. But if that protector has no dedicated
earthing connection, then that protector provides no effective
protection. Plug-in protectors have all but no earth ground.
Serious protector manufacturers have names associated with
responsible manufacturers - Square D, GE, Leviton,
Cutler-Hammer, Polyphaser, Siemens, and Intermatic.
Ineffective protectors are plug in types characterized by: 1)
no dedicated earthing connection, and 2) manufacturer avoids
all discussion of earthing.
Multi-layered protection will help. However many confused
what is meant by multi-layered. Multi-layered is not about
the protector. Multi-layered is about protection. Your
building earth ground is secondary protection. Primary
protection that a building owner must inspect:
http://www.tvtower.com/fpl.html
Defined are two layers of protection. Each layer is
connected either by a copper wire (ie CATV wire) OR is
connected by a 'whole house' protector (AC electric and
telephone). 'Whole house' protectors are so effective that
one is installed, for free, by your telco. However, you - not
they - are responsible for the earth ground. Not just any
earth ground. Single point earth ground. All incoming
utilities must connect, 'less than 10 feet', to single point
earthing. If that incoming phone line does not connect 'less
than 10 feet', through the protector, to single point earth
ground, then you have a compromised protection 'system'.
Yes - 'system'. The protection for that electronic
equipment is a building wide 'system'. The most essential
component of that system is earthing.
That means even if a communication wire connects from one
building to another, that communication wire must first
connect to each building's earthing before entering each
building. Earthing is what an effective surge protector
does. Ineffective protectors completely avoid the earthing
topic.
Point of use protectors hope you never learn this. They
also hope you never learn that electronic equipment already
has internal protection. Any protection that will work on the
power cord is already inside the equipment. Protection that
assumes YOU will earth the incoming transient before it can
enter the building. Without a building wide protection
'system', then protection already inside equipment can be
overwhelmed.
Concepts were well proven long before WWII. Your telephone
switching computer, connected to overhead wires everywhere in
town, need not disconnect during every thunderstorm.
Disconnecting is dependent on something very unreliable - the
human. Furthermore, do you really think a few millimeters
separation inside a power switch will stop what three miles of
sky could not?
Ham radio operators even demonstrated the concept. They
would disconnect equipment from the antenna, put the antenna
lead inside a mason jar, and still suffer damage. However
when they earthed that antenna wire, then damage stopped.
Earthing is the protection - not some protector and not a
power off switch.
For residential buildings, Home Depot (Intermatic) and Lowes
(GE & Cutler-Hammer) sell effective 'whole house' protectors.
Other brands are available through an electrical supply
house. But again, the protection is defined by the quality of
earthing. Some examples of how that earthing becomes single
point:
http://www.cinergy.com/surge/ttip08.htm
http://www.erico.com/public/library/...es/tncr002.pdf
http://www.leminstruments.com/pdf/LEGP.pdf (page 14)
Notice in those figures: even ungrounded utility wires will
carry destructive transients into a building. Every incoming
utility must connect, 'less than 10 feet', to the single
point earth ground. How that earthing is routed and connected
is also important.
But again, the protector is not protection. Layering is
about protection - not about protectors. Building owner is
responsible for installing effective secondary protection -
the single point earth ground. Building owner should verify
that primary protection is also in place and properly
connected. Protection is defined by and is only as effective
as its earth ground - as John has demonstrated.
john wrote:
A couple of extra grounding rods at the service enterance, and if you
have a well, make sure the casing is grounded directly to the service
enterance ground with at least a #4 wire, the larger the better with no
sharp bends.
John