do I need a surge protector?

"w_tom" wrote in message
s.com...
On Feb 24, 8:38 am, Sam Spade wrote:
Some of those of us who have rear-projection LCD TVs with the expensive
light bulb use uninterruptable power suppies, typically a reasonable
size APC unit. The UPS protects as a surge protector and gives you a
chance to properly power down the hot-running bulb in the event of a
power failure.

If a UPS protects as a surge protector, then it says so in numerical
specifications. Yes, it protects from one type of surge. And again,
we have a half truth. That surge is typically not destructive; made
irrelevant by protection already inside electronics.

Meanwhile another type surge that does damage .... well, that UPS
has no dedicated earthing wire. Therefore no protection from a
typically destructive type surge.

Have doubts? Look at UPS's numerical specs. Where is each type of
surge listed and numbers for that protection listed? They don't list
protection because a UPS without that dedicated earthing wire does not
provide protection from all types of surges. What does a building
wide UPS have? That dedicated earthing wire. Notice that building
wide UPSes can provide surge protection. Does that mean plug-in UPSes
also provide protection? Only when junk science makes assumptions.
No earth ground means no effective protection.

Then we look at its number of joules. That plug-in UPSes has so
few joules that ... well again, we are back to a half fact. They have
installed some joules to claim protection from a typically not
destructive surge. Protection so woefully undersized as to do almost
nothing; maybe create smoke. Effective protectors, instead, have
sufficient joules that earth a direct lightning stike AND remain
functional.

How many joules in that UPS?

Any protection on that TV power cord is already inside that TV.
Protection that can be overwhelmed if a rare and destructive surge is
not earthed where it enters the building. This solution is called a
'whole house' protector from manufacturers that have responsible
names. Why is it effective? 1) More joules. 2) Short ('less than 10
foot') connection to an earth ground also used by TV cable and teleco
installed protector.

Cable does not need a protector. TV Cable must be earthed directly
to earth ground by direct wire, where it enters the building, and
'less than 10 feet'. Protectors effective when they make the
conneciton to earth. But cable is earthed where it enters the
building; no protector required to make that connection.

Another here misrepresents what IEEE demands for protection. Again,
something that the UPS does not provide - that short and dedicated
earthing wire. IEEE recommendations are not in papers. IEEE
recommendations are in standards. IEEE Green Book (Standard142)
entitled 'Static and Lightning Protection Grounding' says:
Lightning cannot be prevented; it can only be intercepted or
diverted to a path which will, if well designed and constructed,
not result in damage.

Necessary for protection defined in IEEE Red Book (Standard 141):
In actual practice, lightning protection is achieve by the
process of interception of lightning produced surges,
diverting them to ground, and by altering their
associated wave shapes.

IEEE Emerald Book, "Powering and Grounding Sensitive Electronic
Equipment" (Standard 1100) says:
It is important to ensure that low-impedance grounding and
bonding connections exist among the telephone and data
equipment, the ac power system's electrical safety-grounding
system, and the building grounding electrode system. ...

Does that UPS have a dedicated wire for earthing? Does its
manufacturer avoid discussing earthing? Both questions identify an
ineffective protector. That UPS does not even claim to provide that
protection. UPS only function is to maintain power during blackouts
and extreme brownouts. That is also claims to do in numerical specs.

Does Jame need a protector? Yes. One that connects to an earth
ground also used by TV cable (hardwired) and by telco installed 'whole
house' protector. All protectors or direct connections must make a
'less than 10 foot' connection to the same earth ground as even
required by post 1990 National Electrical Code. And yes, to protect
the TV, even the telephone 'whole house' protector must be earthed so
that destructive surges do not enter the building. Protection is
defined by a single point earthing electrode. Protectors are nothing
more than connections from each utility wire to protection - earth
ground.

Just wondering why you don't consider the ground wire in an outlet as
ground?

As a retired electrical engineer, with many years experience in design,
implementation and maintenance, of communications and security systems,
I take exception to the conclusion of w_tom that surge suppressors are
of no value in protecting electrical operated devices from damage from
power line surges.
Of course no surge protector can guarantee protection from a direct
lightning strike on the incoming powerline, but can still be effective
protection from other causes of power line surges. DO, USE SUPPRESSORS,
preferably find one with telephone line and cable protection. The better
the electrical grounding system in your home or office, the more
effective the surge protectors will be. I could write a lengthy article
on surge protectors, but to simplify selection for the layman, select
one with the highest joule rating consistent with the thickness of your
wallet. Any protection is better than none. If voltage spikes are sharp
enough even tying knots in the power cord could reduce them. That is
because a coil of wire generates a reverse electromotive force opposing
the source.
Back to Ben Franklin; He was extremely lucky he did not become a
surge suppressor with his kite experiment.

"Tom in Macon" wrote in message
.. .

"w_tom" wrote in message
s.com...
On Feb 24, 8:38 am, Sam Spade wrote:
Some of those of us who have rear-projection LCD TVs with the expensive
light bulb use uninterruptable power suppies, typically a reasonable
size APC unit. The UPS protects as a surge protector and gives you a
chance to properly power down the hot-running bulb in the event of a
power failure.

If a UPS protects as a surge protector, then it says so in numerical
specifications. Yes, it protects from one type of surge. And again,
we have a half truth. That surge is typically not destructive; made
irrelevant by protection already inside electronics.

Meanwhile another type surge that does damage .... well, that UPS
has no dedicated earthing wire. Therefore no protection from a
typically destructive type surge.

Have doubts? Look at UPS's numerical specs. Where is each type of
surge listed and numbers for that protection listed? They don't list
protection because a UPS without that dedicated earthing wire does not
provide protection from all types of surges. What does a building
wide UPS have? That dedicated earthing wire. Notice that building
wide UPSes can provide surge protection. Does that mean plug-in UPSes
also provide protection? Only when junk science makes assumptions.
No earth ground means no effective protection.

Then we look at its number of joules. That plug-in UPSes has so
few joules that ... well again, we are back to a half fact. They have
installed some joules to claim protection from a typically not
destructive surge. Protection so woefully undersized as to do almost
nothing; maybe create smoke. Effective protectors, instead, have
sufficient joules that earth a direct lightning stike AND remain
functional.

How many joules in that UPS?

Any protection on that TV power cord is already inside that TV.
Protection that can be overwhelmed if a rare and destructive surge is
not earthed where it enters the building. This solution is called a
'whole house' protector from manufacturers that have responsible
names. Why is it effective? 1) More joules. 2) Short ('less than 10
foot') connection to an earth ground also used by TV cable and teleco
installed protector.

Cable does not need a protector. TV Cable must be earthed directly
to earth ground by direct wire, where it enters the building, and
'less than 10 feet'. Protectors effective when they make the
conneciton to earth. But cable is earthed where it enters the
building; no protector required to make that connection.

Another here misrepresents what IEEE demands for protection. Again,
something that the UPS does not provide - that short and dedicated
earthing wire. IEEE recommendations are not in papers. IEEE
recommendations are in standards. IEEE Green Book (Standard142)
entitled 'Static and Lightning Protection Grounding' says:
Lightning cannot be prevented; it can only be intercepted or
diverted to a path which will, if well designed and constructed,
not result in damage.

Necessary for protection defined in IEEE Red Book (Standard 141):
In actual practice, lightning protection is achieve by the
process of interception of lightning produced surges,
diverting them to ground, and by altering their
associated wave shapes.

IEEE Emerald Book, "Powering and Grounding Sensitive Electronic
Equipment" (Standard 1100) says:
It is important to ensure that low-impedance grounding and
bonding connections exist among the telephone and data
equipment, the ac power system's electrical safety-grounding
system, and the building grounding electrode system. ...

Does that UPS have a dedicated wire for earthing? Does its
manufacturer avoid discussing earthing? Both questions identify an
ineffective protector. That UPS does not even claim to provide that
protection. UPS only function is to maintain power during blackouts
and extreme brownouts. That is also claims to do in numerical specs.

Does Jame need a protector? Yes. One that connects to an earth
ground also used by TV cable (hardwired) and by telco installed 'whole
house' protector. All protectors or direct connections must make a
'less than 10 foot' connection to the same earth ground as even
required by post 1990 National Electrical Code. And yes, to protect
the TV, even the telephone 'whole house' protector must be earthed so
that destructive surges do not enter the building. Protection is
defined by a single point earthing electrode. Protectors are nothing
more than connections from each utility wire to protection - earth
ground.

Just wondering why you don't consider the ground wire in an outlet as
ground?

An outlet ground is more of a safety ground (protection from electrocution
or fire). There is some resistance back to earth from any outlet. The best
spot for surge protection is at the panel as the earth ground is only feet
away from the actual earth and electricity follows the path of least
resistance. A cheaper surge protection strip at each device can offer some
protection in case the panel device fails or there's a localized
interference.

On Feb 24, 12:39 pm, "Tom in Macon" wrote:
Just wondering why you don't consider the ground wire in an outlet as
ground?

AC electric is affected by wire resistance. That means a wall
receptacle safety ground via 50 feet of Romex wire might be less than
0.2 ohms resistance to earthing electrode. But for surges, wire
impedance is the dominant parameter. That same 50 foot wire may be
120 ohms impedance.

Let's say the plug-in protectors must earth a trivial 100 amp
surge. 100 amps times 120 ohms means voltage may approach 12,000.
Bud's own citation shows this problem with a TV charged to 8000 volts
- destructively - because the plug-in protectors has all but no earth
ground.

These numbers assume that 50 foot ground wire has no sharp bends, no
splices, does not pass through metallic conduit, etc. Those factors
increase wire impedance.

Not only must a protector make a 'less than 10 foot' connection -
for low impedance. Earthing also must exceed requirements of post
1990 National Electrical Code. No sharp bends, no splices, as short
as possible, AND not bundled with other non-earthing wires. If
earthing a transient via wall receptacle safety ground, well, that
Romex ground wire is bundled with and induces transients on other
wires. Just another reason why wall receptacle safety (equipment)
ground is not sufficient as earth ground.

How must that earthing wire be routed? Up above the breaker box,
over the foundation, then down to an earthing electrode? No. Too
long, probably bundled with other wires, and too many bends. Earthing
wire is best run through foundation for a shorter distance to earthing
electrode. Lower wire impedance on that earthing conductor makes a
protection 'system' even more effective.

Remember what makes a protector effective: its earthing electrode
and how that connection is created.

To promote plug-in protectors, its manufacturer simply avoids
discussing this. Somehow a wall receptacle makes a perfectly good
connection to earth? No. They avoid an earthing discussion. Profits
are too large. Look at Monster Cable. Monster knows, instead, to
charge many times more. Then people will 'assume' it is better.
'Assume' is what promotes plug-in and Monster Cable protectors. Why
would they (or Circuit City) discuss earthing? Profits are too high
by telling half truths.

Meanwhile, in another post, you cautioned:
... make sure the surge protection circuit has not been
used destroyed by a surge.

Well how do you know? A properly sized protector degrades - does
not vaporize as indicated by lights. Threshold voltage on a degraded
protector only changes by 10%. That light? It only reports that the
protector components were so grossly undersized as to vaporize.
Undersizing a protector maximizes profits. Effective protectors must
earth the transient AND remain functional. A degraded protector is
not indicated by those lights. Just another fact that a plug-in
protector manufacturers will forget to mention.


Remember, a TV cable (properly installed) is earthed. A shorter and
destructive path from surge protector to earth: through adjacent TV
and to earth via TV coax cable. Now a protector, adjacent to TV, has
simply contributed to damage of that TV. Surge uses TV to find earth
when wall receptacle safety ground wire higher impedance.

But a few reasons why AC wall receptacle safety ground is not earth
ground. Also reasons why your telco does not use plug-in protectors
in facilities that must never suffer damage. Why does the telco
install a 'whole house' protector, for free, at your building?
Because it is so inexpensive and so effective when properly earthed.

On Feb 24, 12:54 pm, (Liam R) wrote:
As a retired electrical engineer, with many years experience in design,
implementation and maintenance, of communications and security systems,
I take exception to the conclusion of w_tom that surge suppressors are
of no value in protecting electrical operated devices from damage from
power line surges.

w_tom never said what Liam R has misrepresented. w_tom noted that a
protector without earthing will not earth a typically destuctive
surge. Earthing is the protection. Protector is simply a connecting
device to protection - earthing. Protector is necessary to earth AC
electric and telephone wires.

Where to put the power strip protector? On the AC receptacle
adjacent to a mains breaker box. Then it might earth something.

One need not have a fat wallet to install effective protection. One
needs a fat wallet for ineffective plug-in protectors. 'Whole house'
protectors with minimally sufficient joules AND the dedicated earthing
wire are sold in Lowes and Home Depot for less than $50. That's about
$1 per protected appliance. Why would anyone spend $125 for a
protector that does not even claim to protect? Why would anyone spend
$125 per protected appliance for a protector that does not even claim
to work?

Joules and earthing make a protector effective. w_tom strongly
recommends surge protectors that work - which means less money for
better protection - which is not a plug-in type without an earthing
wire.

bud-- wrote:

(the IEEE is the dominant organization of electrical and electronic
engineers in the US).

Huh... So the "I" stands for *I*n the US??? Silly me, always thinking
that it stood for *I*nternational...

;-)

Carlos
--

"w_tom" wrote in message
ps.com...
On Feb 24, 12:39 pm, "Tom in Macon" wrote:
Just wondering why you don't consider the ground wire in an outlet as
ground?

AC electric is affected by wire resistance. That means a wall
receptacle safety ground via 50 feet of Romex wire might be less than
0.2 ohms resistance to earthing electrode. But for surges, wire
impedance is the dominant parameter. That same 50 foot wire may be
120 ohms impedance.

Let's say the plug-in protectors must earth a trivial 100 amp
surge. 100 amps times 120 ohms means voltage may approach 12,000.
Bud's own citation shows this problem with a TV charged to 8000 volts
- destructively - because the plug-in protectors has all but no earth
ground.

These numbers assume that 50 foot ground wire has no sharp bends, no
splices, does not pass through metallic conduit, etc. Those factors
increase wire impedance.

Not only must a protector make a 'less than 10 foot' connection -
for low impedance. Earthing also must exceed requirements of post
1990 National Electrical Code. No sharp bends, no splices, as short
as possible, AND not bundled with other non-earthing wires. If
earthing a transient via wall receptacle safety ground, well, that
Romex ground wire is bundled with and induces transients on other
wires. Just another reason why wall receptacle safety (equipment)
ground is not sufficient as earth ground.

How must that earthing wire be routed? Up above the breaker box,
over the foundation, then down to an earthing electrode? No. Too
long, probably bundled with other wires, and too many bends. Earthing
wire is best run through foundation for a shorter distance to earthing
electrode. Lower wire impedance on that earthing conductor makes a
protection 'system' even more effective.

Remember what makes a protector effective: its earthing electrode
and how that connection is created.

To promote plug-in protectors, its manufacturer simply avoids
discussing this. Somehow a wall receptacle makes a perfectly good
connection to earth? No. They avoid an earthing discussion. Profits
are too large. Look at Monster Cable. Monster knows, instead, to
charge many times more. Then people will 'assume' it is better.
'Assume' is what promotes plug-in and Monster Cable protectors. Why
would they (or Circuit City) discuss earthing? Profits are too high
by telling half truths.

Meanwhile, in another post, you cautioned:
... make sure the surge protection circuit has not been
used destroyed by a surge.

Well how do you know? A properly sized protector degrades - does
not vaporize as indicated by lights. Threshold voltage on a degraded
protector only changes by 10%. That light? It only reports that the
protector components were so grossly undersized as to vaporize.
Undersizing a protector maximizes profits. Effective protectors must
earth the transient AND remain functional. A degraded protector is
not indicated by those lights. Just another fact that a plug-in
protector manufacturers will forget to mention.


Remember, a TV cable (properly installed) is earthed. A shorter and
destructive path from surge protector to earth: through adjacent TV
and to earth via TV coax cable. Now a protector, adjacent to TV, has
simply contributed to damage of that TV. Surge uses TV to find earth
when wall receptacle safety ground wire higher impedance.

But a few reasons why AC wall receptacle safety ground is not earth
ground. Also reasons why your telco does not use plug-in protectors
in facilities that must never suffer damage. Why does the telco
install a 'whole house' protector, for free, at your building?
Because it is so inexpensive and so effective when properly earthed.

Hmm. Seems like we had to have a gound resistance of less than 2 ohms to
ground on work benches used in Navy electronics. This was seldom achieved
and not because of bad wiring, but because the ground electrode sunk into
the ground almost always showed more than 2 ohms. True ground is hard to
achieve because of soil moisture content and soil conductivity. And no, we
didn't use a simple ohm meter to take the measurements, but an instrument
that used 3 rods sunk in the ground and a bridge type meter to take the
measurement.
Personally, I think the surge protectors will work fine on most home
applications. The surge protector on my computer says it will suppress to
330V, and that is all I am asking it to do.

Carlos Moreno wrote:
bud-- wrote:

(the IEEE is the dominant organization of electrical and electronic
engineers in the US).


Huh... So the "I" stands for *I*n the US??? Silly me, always thinking
that it stood for *I*nternational...

;-)

Carlos
--

IEEE (Institute of Electrical and Electronics Engineers)

A world wide organization...
http://www.ieee.org/web/geo_activities/home/index.html

Dominant without being exclusive to US.

"Jane" wrote in message
ups.com...
Just bought a Samsung 46" HDTV at Circuit City. They tried to talk me
into a very expensive surge protector. They also said I MUST have a
Monster HDMI cable for $125 which I later found out was bull. So I
decided to wait on their surge protector and ask you guys out there
for advice.

Do I need it? What brand is best? I have a really good one for my
computer but it's paid for by my company. I also have a Liebert which
costs about $30 but I believe is meant mostly for computers, or are
they generic?

No one needs ANYTHING made by Monster.
They might as well change the name of the company to Fraud Inc.

However, a quality surge protector is a wise investment for home theater.
There are many on the market, even the best are less than $50. The Joule
rating is the amount of energy the surge arrestor can swallow without
blowing up - higher is better. Your Liebert is better than fine.

On Feb 24, 8:08 pm, "Tom in Macon" wrote:
Hmm. Seems like we had to have a gound resistance of less than 2 ohms
to ground on work benches used in Navy electronics. ...
Personally, I think the surge protectors will work fine on most home
applications. The surge protector on my computer says it will suppress to
330V, and that is all I am asking it to do

2 ohms is earthing electrode resistance - not related to anything
posted above. Discussed was impedance between the appliance and that
electrode. 120 ohm impedance is unchanged whether earthing electrode
was 2 ohms or higher. Mentioning 2 ohms ground resistance is
irrelevant to impedance in wires. Making 2 ohms as low as possible
addresses something different.

Also not relevant is another parameter called let-through voltage.
Protector remains inert - acts just like a $3 power strip - until
voltage between two wires exceeds 330 volts. Does that 330 volts on
a 120 volt TV cause damage? No, because internal TV protection even
makes 600 volts irrelevant.

That 330 volts may exist between any two AC wires. But a
completely different voltage, 12,000 volts, can exist
simultaneously. Current creating 12,000 volts could pass right
through a power strip, no even create 330 volts inside that protector,
and still destructively damage adjacent electronics. Protector does
nothing to protect and may even contribute to adjacent electronics
damage.

A car radio hooked to a 12 volt battery. To protect that radio, we
put a 50 volt protector across radio's power wires. Somebody connects
1000 VAC only to one battery terminal. Does that 50 volts protector
see the 1000 volts? Of course not. 50 volt protector only sees 12
volts as 1000 volts passes through radio, out antenna wire, and
destroys the radio. Your 330 volt plug-in protector performs just
like that 50 volt radio protector. This circuit also demonstrates how
why a 330 volt plug-in protector does not protect the adjacent TV.

Let's return to Jane's TV. Assume your 330 volts protector is
adjacent. A surge comes down all AC wires seeking earth ground. Your
protector may or may conduct surge current from one wire to others.
Will that surge seek earth ground down a safety ground wire that is
now charged at something less than 12,000 volts? Not when surge has a
better path to earth, destructively, through Jane's TV and coax cable.

Your plug-in protector did nothing to prevent and might contribute
to damage of Jane's TV just like that 50 volt protector did not
protect the 12 volt radio. Plug-in protector is just as ineffective in
the home as in telco facilities and 911 emergency response centers. A
plug-in protector too far from earth ground and too close to TV does
not even claim to provide protection. Worse, that plug-in protector
costs $25 or $125 per protected appliance. Damage prevented if using
a 'less than 10 foot' connection of a 'whole house' protector costing
about $1 per protected appliance. Your protector is 25 and 100 times
more expensive - and does not even claim to provide that protection.
Just another reason why high reliability facilities do not use a plug-
in protector that is not effective and costs excessive.