Plug-in protectors do not work primarily by earthing a surge.
The IEEE surge guide (link in trader's post) explains (starting page 30)
plug in protectors work by limiting the voltage from each wire (power
and signal) to the ground at the protector. The voltage between the
wires going to the protected equipment is safe for the protected equipment.
Since protection is by limiting the voltage between wires, all
interconnected equipment needs to be connected to the same protector and
all external connections, like coax, must go through the protector.
Suppose you have a house earthed with a ground rod having near
miraculous 10 ohms resistance to earth (and ignoring the impedance of te
connecting wire), and a 1,000A surge is earthed. The building "ground"
system will rise 10,000A above 'absolute' earth potential. In general
70% of the voltage drop away from a ground rod is in the first 3 feet.
The earth over 3 feet away will be at least 7,000V from the building
Much of the protection is that all wiring - power, phone, cable, ... -
rises together. That requires a short ground wire from phone and other
entry protectors to a common connection point on the power earthing
system. (An example of a ground wire that is too long is in the IEEE
surge guide starting page 30.)
A surge expert at the NIST has written "the impedance of the grounding
system to `true earth' is far less important than the integrity of the
bonding of the various parts of the grounding system."
That was our experience. In places with very long data lines, we
actually bonded the cases of the machines together with a large wire
that was significantly shorter than the signal wire. You can use
ferrite beads to essentially "lengthen" the signal wire but we also
looped up some extra data cable through the ferrite. That stopped the
problem of losing POS terminals in pool bars every time it rained.
"Ground" is a misnomer anyway. We have documented several volts
difference between the electrode systems of buildings that were less
than 100' apart. That causes it's own problems. You also have the
problem that in why distribution, the PoCo is using earth as a
parallel return path to that little neutral wire they have in the
distribution system. There is a significant amount of current in those
8ga wires you see going down the pole from a transformer. There is no
rod at the end of that wire. it is just tacked to the bottom of the
pole before they set it.
There is almost 3 amps on this one. (on the single phase distribution
This one is where the 3 phases of the distribution split out. (less
than an amp)
firstname.lastname@example.org posted for all of us...
I touched one of these one time on the way to school when I was a kid and
got shocked. I didn't tell my parents-they would have just told me to keep
my hands off things that don't belong to me... I learned a lesson but I
wonder if contributed to my lack of brain power...
On Wednesday, May 18, 2016 at 10:56:06 PM UTC-4, Steve Stone wrote:
If a washer needs protection, then so does every household item including c
locks, RCD, furnace, recharging phones, and the most critical item during a
surge - smoke detectors. Nothing adjacent to an appliance claims to prote
ct from destructive surges. Protection means a surge is connected to earth
BEFORE it enters a building. No way around that well proven science.
Does not matter if AC service is overhead or underground. Risk from surges
(lightning and other sources) remains. Even underground wires can carry a
direct lightning strike into a building. Every wire in every incoming cab
le must connect to single point earth ground BEFORE entering. Otherwise a
surge is inside hunting for earth destructively via appliances. Earth grou
nd (not a protector) is the most critical component in every protection 'sy
What does an adjacent protector do? MOVs might connect that surge from hot
wire to neutral or safety ground wires. Now that surge has even more path
s to find earth ground destructively via a washer or other nearby appliance
. Adjacent protectors can even make damage easier if a 'whole house' solut
ion is not implemented.
All appliances contain robust protection. Your concern is a rare transient
that might occur once every seven years. That transient must be connected
low impedance (ie less than 3 meters) to earth BEFORE entering. Otherwise
it will go hunting for earth destructively via appliances. Nothing adjace
nt to an appliance claims to 'block' or 'absorb' that transient. If anythi
ng needs that protection, then everything needs that protection.
On Thursday, May 19, 2016 at 11:10:53 AM UTC-4, westom wrote:
clocks, RCD, furnace, recharging phones, and the most critical item during
a surge - smoke detectors. Nothing adjacent to an appliance claims to pro
tect from destructive surges. Protection means a surge is connected to ear
th BEFORE it enters a building. No way around that well proven science.
es (lightning and other sources) remains.
Sure it remains. But it does matter. With an underground service, the
lines leading from the street to the house, the masthead, etc are not
present and can't be hit by a direct lightning strike. Less target is
better than more target.
Even underground wires can carry a direct lightning strike into a buildin
g. Every wire in every incoming cable must connect to single point earth g
round BEFORE entering. Otherwise a surge is inside hunting for earth destr
uctively via appliances. Earth ground (not a protector) is the most critic
al component in every protection 'system'.
ot wire to neutral or safety ground wires. Now that surge has even more pa
ths to find earth ground destructively via a washer or other nearby applian
ce. Adjacent protectors can even make damage easier if a 'whole house' sol
ution is not implemented.
You can listen to Tom or you can read what the electrical engineers that
specialize in surge protection say at IEEE and NIST. Both groups say
that point-of-use surge protectors do work, endorse them as part of a tiere
approach and standalone too.
Not as robust as the protection in a quality plug-in surge protector.
That transient must be connected low impedance (ie less than 3 meters) to
earth BEFORE entering. Otherwise it will go hunting for earth destructive
ly via appliances. Nothing adjacent to an appliance claims to 'block' or '
absorb' that transient. If anything needs that protection, then everything
needs that >protection.
Plug-ins/point-of-use work by clamping all the inputs to the same level.
I'm sure the usual W Tom rant will be forthcoming.
On Thu, 19 May 2016 08:25:40 -0700 (PDT), trader_4
Tom sells whole house protection and you definitely need it, connected
to a good grounding electrode. The only thing Tom disagrees about is
whether a point of use protector does anything. I do believe it will
damp out locally induced shots that get into the system after it
enters the house.
That would typically be an EMP that comes from lightning hitting a
tree in the back yard.
I have survived direct hits on a weather station on my garage ...
twice ... but I have pretty good protection in several layers
including on the signal line from the weather station..
On Thursday, May 19, 2016 at 2:44:30 PM UTC-4, email@example.com wrote:
We don't sell these things. We installed effective protection. Direct lig
htning strike without damage were routine. In one venue, all wires were un
derground. Since single point earthing was missing, all computers in the b
lock house (on surge protectors) were damaged. That strike to earth was a
direct strike to underground wires.
I never said plug-in protectors do nothing. Constantly stated is that it o
nly does what it claims to do - nothing more. To protect from a type of su
rge that typically causes no damage; a transient made irrelevant by robust
protection inside every appliance. A plug-in protector does exactly what i
t claims to do. It does not claim to protect from the other and typically
destructive type of surge. Lightning is but one example of that other type
A tree struck by lightning can be a direct connection to incoming conductor
s - especially buried wires or metal pipes. EMP did not cause damage. Curr
ent in a tree is then passing into buried conductors to causes damage. Usi
ng appliances as part of the path that connects to earthborne charges maybe
4 kilometers distant. That same current can be so harmful as to even kill
four legged animals.
That current through a struck tree is especially destructive when all incom
ing conductors do not enter at a common service entrance. Makes little dif
ference whether those conductors are overhead or underground since both nee
d same properly earthed protection.
International design standards defined internal protection for electronics
long before PCs existed. It is not debatable. Otherwise that other's deni
als included numbers - not personal speculation. Surges that are hundreds
of joules are routinely converted into rock stable, low DC voltages to safe
ty power semiconductors. Tiny joule (plug-in) protectors, doing what its m
anufacturer claims, are doing near zero protection. It does exactly what t
he manufacturer says it will do.
The QO Surgebreaker designed for and supplied by Square D for the QO
panel is just over $100 Canadian, so likely about $50 street price in
the USA. Add the cost of a good ground.if you do not already have it.
On Friday, May 20, 2016 at 5:10:47 AM UTC-4, Just Joe wrote:
About $1 per protected appliance.
Solution does not use products with obscene profit margins from APC, Belkin
, Tripplite, Panamax, Monster or Bud. An effective system would feature pr
otectors from other companies with integrity such as Intermatic, Square D,
Ditek, Siemens, Polyphaser (an industry benchmark), Syscom, Leviton, ABB, D
elta, Erico, General Electric, and Cutler-Hammer. It should be rated at le
ast 50,000 amps. These are available in any electrical supply house, and i
n both Lowes and Home Depot.
Protector at 50,000 amps defines system reliability (life expectancy) 'over
More important is its single point earth ground - the item that harmlessly
absorbs hundreds of thousands of joules. Earthing the art of protection an
d should have most of your protection. Earthing defines protection during
I have nothing to do with surge protection other than what I use.
If westom had valid technical arguments he wouldn't have to lie.
At least half of these "companies with integrity" make and sell plug-in
SquareD does not, and makes service panel protectors. Last time I looked
SquareD said for their "best" service panel protector "electronic
equipment may need additional protection by installing plug-in
[protectors] at the point of use."
For the next best protector, SquareD said the connected equipment
warranty $ does not include "electronic devices such as: microwave
ovens, audio and stereo components, video equipment, televisions, and
Because square D says their whole house surge protectors are "non
filtering" - iow, they do not address low energy or high frequency
"noise" superimposed on the line - which a good "computer grade
The spec on a relatively low-priced Noma says response time under 1
nanosecond, maximum current spike 39,000 amps, maximum voltage
clamping 330 volys, and maximum surge energy 925 joules.
It "absorbs transient energy by blocking power vsurges from ac power
lines and phone/modem lines"
The dual mode UPS filtering specs are:
common mode noise rejection >60dB @ 100kHz
Transverse mode noise rejection >80dB @ 100kHz
Surge protection excedes IEEE 587/ANSI C62 41 Category A abd B
On 5/21/2016 12:07 PM, firstname.lastname@example.org wrote:
All service panel protectors are "non-filtering". Filtering would
require the protector to be wired in series with the service.
I have seen no evidence that "noise" is a problem. You feed "noise" into
a switch-mode power supply and it is removed at the input DC conversion,
which is a giant low-pass (zero frequency) filter.
You do not say what this is. Looks like a plug-in protector.
"Absorbs" and "blocking" are technically incorrect, but probably more
understandable. "Clipping" more accurately describes what happens.
All MOV based protectors are fast enough (1 nanosecond).
From the NIST surge expert:
"The fact of the matter is that nowadays, most electronic appliances
have an inherent immunity level of at least 600 V to 800 V, so that the
clamping voltages of 330 V widely offered by [surge protector]
manufacturers are really not necessary. Objective assessment of the
situation leads to the conclusion that the 330 V clamping level,
promoted by a few manufacturers, was encouraged by the promulgation of
UL Std 1449, showing that voltage as the lowest in a series of possible
clamping voltages for 120 V circuits. Thus was created the downward
auction of "lower is better" notwithstanding the objections raised by
several researchers and well-informed manufacturers. One of the
consequences of this downward auction can be premature ageing of [surge
protectors] that are called upon to carry surge currents as the result
of relatively low transient voltages that would not put equipment in
If peak let-through is other than 330V there needs to be coordination
between service panel and plug-in protectors.
I have seen no evidence that noise is a problem
If I am buying a UPS or plug-in protector I want it listed under UL1449,
which is the surge protector standard, and means the device has been
tested by UL. There are a couple other UL standards for phone and cable
"Exceeds" means the manufacturer is claiming the device meets the
standards (which are not UL1449).
On Friday, May 20, 2016 at 5:10:47 AM UTC-4, Just Joe wrote:
BTW, you should also inspect the protection installed for free by the telco, cable company, and satellite dish. Dish installers are particularly bad. And inspect your 'primary' protection layer as detailed elsewhere.
On Friday, May 20, 2016 at 4:12:20 AM UTC-4, westom wrote:
ightning strike without damage were routine. In one venue, all wires were
underground. Since single point earthing was missing, all computers in the
block house (on surge protectors) were damaged. That strike to earth was
a direct strike to underground wires.
You sure have said that and far worse over the years.
e. To protect from a type of surge that typically causes no damage; a tran
sient >made irrelevant by robust protection inside every appliance.
And so it begins. Again what you're saying is contradictory to what the
electrical engineer experts in surge protection that wrote both the NIST
and IEEE guides clearly say in those guides. Readers are encouraged to
read them. They show plug-in type surge protectors being used. Which
would of course make no sense if they are irrelevant by "robust" protection
inside every appliance. Open up those appliances and you'll find small
MOVs. Look inside a decent plug-in and you'll find ones that are many
times larger. And notice who provided the links to those guides and who
On Fri, 20 May 2016 06:21:19 -0700 (PDT), trader_4
Tom is very effective in selling his Polyphaser and he dismisses point
of use protectors because he doesn't have them to sell.
My experience was built up over many years and thousands of customers
in Florida who were not going to power off their computers, ATMs and
cash registers every afternoon and unplug them. There is no single
solution. Real protection involves many layers of protection. In some
cases we went as far as to bond the cases of interconnected equipment
together with fat wire because that is what it took to minimize those
"interior transients" that Tom thinks are harmless. We also used
ferrite beads on signal wires and other methods to mitigate transients
that showed up on the load side of the service entrance.
When lightning hit the lightning rod above my weather station, it
completely bypassed anything on the service entrance ... but my PC and
the station survived.
The surges a plug in surge protector protects from are not the ones
that do instant catastrophical damage, but the ones that to damage a
little bit at a time - causing things like hard drive failures and
accellerated aging of components.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.