On Apr 8, 3:14 pm, "DD" someone@somewhere wrote:
"Andy Burns" wrote in message
A power surge last week and one fried tv later, and we now discover that
the cheap ones are hardly worth having! Did not realise there were
different standards of surge protection.
...
They are Masterplug and only seem to come with a 3 year guarantee. They are
at least 7 years old (one is dated 1999) and we have looked and can't find
any receipts or the package inserts we thought we kept.
Its so called warranty is full of exceptions. That warranty is just
not honored as others before have learned. A big quid equipment
guarantees is essentially useless. Meanwhile real world protectors
mean no damage.
Multiple type of surges exist. Type that typically damages seeks
earth ground. Another will post a citation where page 42 Figure 8
shows a plug-in protector earthing a surge, 8000 volts destructively,
through the TV. That surge protector had no dedicated earthing wire
for the 'less than 3 meter' earthing connection. That earthing wire
is the difference between ineffective plug-in protectors and effective
solutions.
How to identify the ineffective protector? 1) No dedicated earthing
wire and 2) manufacturer avoids all discussion about earthing. Simple
rule. Notice your protectors and therefore resulting damage violated
both points.
Protectors are not protection. Protectors are simply a connecting
device between each utility wire and earth ground. No three meter
earthing wire? Then a surge protector must earth that surge maybe via
TV or computer.
Every wire incoming to the home is the equivalent of an antenna to
each appliance. Lightning seeks earth ground via antenna wires; as
via any other incoming utility wire. Effective protection must be
applied to every incoming utility wire. Earthing 'system' must be the
best earthing - often enhanced beyond what electrical codes demand.
Earthing - not the protector - defines protection.
An application noted demonstrates the principles:
http://www.erico.com/public/library/...es/tncr002.pdf
Even buried wires must connect to that earthing electrode before
entering a structure.
Cable TV and dish satellite wires need no protector; connect 'less
than 3 meters' to that earthing electrode via a hardwire. AC electric
and telephone wires make that connection via a 'whole house'
protector. Some examples:
http://www.keison.co.uk/furse/furse06.htm
http://www.keison.co.uk/furse/pdf/ma...lies/m2_m4.pdf
http://www.one.co.uk/catalogue/teleb...otect/22PX.HTM
http://www.keison.co.uk/furse/furse11.htm
http://www.citelprotection.com/engli..._B380_B480.PDF
http://www.keison.co.uk/furse/furse08.htm
An industry professional demonstrates the principle and its
effectiveness:
http://www.harvardrepeater.org/news/lightning.html
Well I assert, from personal and broadcast experience spanning 30 years,
that you can design a system that will handle *direct lightning strikes* on a
routine basis. It takes some planning and careful layout, but it's not hard,
nor is it overly expensive. At WXIA-TV, my other job, we take direct
lightning strikes nearly every time there's a thunderstorm. Our downtime
from such strikes is almost non-existant. The last time we went down from
a strike, it was due to a strike on the power company's lines knocking
*them* out, ...
The belief that there's no protection from direct strike damage is *myth*. ...
The keys to effective lightning protection are surprisingly simple, and
surprisingly less than obvious. Of course you *must* have a single point
ground system that eliminates all ground loops. And you must present a
low *impedance* path for the energy to go. That's most generally a low
*inductance* path rather than just a low ohm DC path.
How a surge protector connects a surge to earth defines an effective
or ineffective 'system'. No 'magic box' will stop or absorb what 4
kilometers of sky could not - as plug-in protectors claim.
Demonstrated by example: a plug-in protector without THE most critical
'system' component (single point earth ground) and damage resulted.
How do you know it will not be effective? No 'less than 3 meter'
earthing connection. No earth ground means no effective protection.