Re: "chain" surge suppressers?

w_tom wrote:


Apparently you missed an important point. An example. How must
resistance in that 50 foot of Romex from wall receptacle to breaker
box?. Less than 0.2 ohms resistance. Therefore a 100 amp surge (60
Hertz) would result in less than 20 volts difference between breaker
box and receptacle. However wire impedance - not resistance - is the
dominate factor during surges. That same romex wire is maybe 120 ohms
impedance. A tiny 100 amp surge would put that receptacle at
something less than 12,000 volts. What will that 100 amp current do?
At 12,000 volts, its will find other (destructive) paths to earth.
Same point is in a Bud citation - Page 42 Figure 8. Adjacent TV
earths 8000 volts destructively because a plug-in protector has no
safe place to earth surge current.

I Don't agree.



Putting the 'whole house' protector adjacent to a ground rod does
not improve the electrode. Putting a protector 'less than 10 feet'
from a ground rod causes massive impedance reduction. Why? Wire
resistance is irrelevant. Wire impedance makes or breaks surge
protection. A protector is only as effective as its earthing
electrode and its connection to that electrode. See, for example, the
legendary applications notes from an industry benchmark - Polyphaser.
What do Polyphaser discuss most? Not their protectors. Polyphasers
legendary app notes discuss earthing and connections to that earth
ground.. Earthing - not the protector - defines protection. Wire
impedance is why that connection to earth must be short - why telcos
also put protectors at the service entrance:.
http://www.polyphaser.com/technical_notes.aspx


I don't agree.


Polyphaser even makes a protector with no earth ground connection.
Why? Impedance so critical that a Polyphaser protector mounts direct
ON earth ground - zero foot connection.


Wire impedance is why telcos install protectors at the service
entrance. Why do telcos not install protectors inside the building?
Not because it is easier. Any protector that would work inside a
building is already inside telephone equipment. But the typically
destructive surge must be earthed by a low impedance earthing
connection before entering the building. Every properly installed
protection (without or without a protector) is wired to make that
short (low impedance) connection to a common earthing electrode. Low
impedance is not relevant to 60 hertz electricity. Wire resistance is
irrelevant to surge protection. Low impedance is essential to surge
protection.

I already answered this. One protector is a lot cheaper than 4 scattered
throughout the house.




Why do responsible manufacturers provide a 'whole house' protector?
Because a plug-in protector does not protect from typically
destructive surges. Every responsible source states that earthing is
essential to surge protection. For example, "Planning guide for Sun
Server room"

"Earthing" would be critical to a lightning surge. A power plant surge is
not returning to earth, its returning to the plant. The return path is the
critical key. Is that path through your device, or through the ground.
And how do you get the surge to prefer the ground over the ordinary path.

Section 6.4.7 Lightning Protection
Lightning surges cannot be stopped, but they can be diverted.
The plans for the data center should be thoroughly reviewed
to identify any paths for surge entry into the data center. Surge
arrestors ... should divert the power of the surge by providing a
path to ground for the surge energy.

ARRL's QST Magazine in July 2002:
The purpose of the ground connection is to take the energy
arriving on the antenna feed line cables and control lines (and
to a lesser extent on the power and telephone lines) and give it
a path back to the earth, our energy sink. The impedance of
the ground connection should be low so the energy prefers this
path and is dispersed harmlessly. To achieve a low impedance
the ground connection needs to be short (distance), straight,
and wide.


Earth does not sink energy that it does not create. Earth ground is only
relevant for lightning surges.


"The impedance of the ground connection ..." is not resistance.
Impedance is why a plug-in protector cannot earth a typically
destructive surge; why telcos routinely put protectors farther from
electronics and as close to earth ground as is practicable.

How does a plug-in protector resolve this low impedance earthing
requirement? Manufacturer pretends no such requirement exists.
Manufacture pretends that surge energy will somehow magically
disappear if wires are shunted together. Manufacturer makes no
protection claims in specifications. The type of surge that typically
causes damage not only needs a low impedance (ie 'less than 10 foot')
connection to earth. It also needs the only necessary 'system'
component that absorbs surge energy - earth ground.

Surges must return to their originator. That may be earth, it may be the
power company.


http://www.telebyteusa.com/primer/ch6.htm
Conceptually, lightning protection devices are switches to
ground. Once a threatening surge is detected, a lightning
protection device grounds the incoming signal connection
point of the equipment being protected. Thus, redirecting
the threatening surge on a path-of-least resistance
(impedance) to ground where it is absorbed.
Any lightning protection device must be composed of two
"subsystems," a switch which is essentially some type of
switching circuitry and a good ground connection-to allow
dissipation of the surge energy.


True.

How many professionals do you need? This EE was doing this stuff
decades ago – maybe longer than you existed. How many of your
protector designs have been tested by direct lightning strikes? How
many failed before you finally learned what provides effective
protection? He who learned the theory and gained decades of
experience says one ‘whole house’ protector provides a massively
better protection system for tens or 100 times less money.



If you are an EE then lets get down to the fundamentals of why you
think "impedance" and not RELATIVE impedance is the key here!? I don't
need citations that you think support your point. Just explain the
fundamentals of your point.



CL
.

Relevant Pages

  • Re: Band Uisng Tripplite Line Conditioners/surge-suppressor
    ... But put a 100 amp surge on that same Romex wire. ... approaching 12,000 volts, it is not earth ground. ... Therefore voltage increases to dissipate more energy ... Cable TV needs no surge protector. ...
    (alt.guitar.amps)
  • Re: Surge protection without grounded plugs
    ... like 130 ohms impedance to the surge. ... protector attempts to earth a trivial 100 amp surge via neutral wire? ... The effective protector earths before that surge gets anywhere near ... Surge that damaged electronics seeks earth ground. ...
    (sci.electronics.basics)
  • Re: MOVs and surge suppressors
    ... It does not know about 'ground' or 'earth'. ... A surge has energy. ... Therefore protector was at 8000 volts on all wires. ...
    (sci.electronics.basics)
  • Re: MOVs and surge suppressors
    ... It does not know about 'ground' or 'earth'. ... A surge has energy. ... Therefore protector was at 8000 volts on all wires. ...
    (sci.electronics.basics)
  • Re: AC Power Adapter
    ... involve surge type, size, duration, etc.. ... The term "also define low impedance earthing. ... for MOV degrading - and no destruction. ... A destroyed protector? ...
    (microsoft.public.windowsxp.help_and_support)