On Apr 2, 1:18 pm, wrote:
"What happens when a surge comes down any or all black,
white, and green wires; and leaves via phone wire, wooden
table, linoleum floor tile, or any other conductive material?
Latter is the surge that does damage. When it leaves,
where does it go? Earth ground. "
In the above, he acknowledges that a surge can come in via the power
line and then exit via everything from a phone wire to a wood table.
Yet he refuses to acknowledge that it could also leave via a point of
use surge protector shunting the surge to ground. And it would seem
that would be a much lower impedance path than a wood table.
Where Tom goes astray is he starts with good advice, which is that
surge protection on the AC panel with a good ground is the most
effective and good practice. But then he quickly decends into
nonsense, when he claims that point of use protectors offer no
protection at all and are actually destructive. Another of his rants
that I like is that all appliances have surge protection already built
into them. Hmmm, let me think....
What would I rather have get blown due to a surge? The MOV in
a $20 plug in protector or the MOV in a $2000 HDTV?
Does all of a surge only go down one wire or only down another
wire? Of course not. And yet going down only one wire must happen
for effective surge protection. Trader, it does not matter if some of
a surge takes that path to ground. Most all of it must. That ground
wire is only low resistance - not low impedance. Therefore too much
surge finds other destructive paths. You are still denying that high
impedance even after page 42 Figure 8 shows high impedance - 2000
volts.
Surge comes down a black wire seeking what? Earth ground. Surge is
shunted from black wire to green wire by protector ... still seeking
earth ground. Some surge current uses green 'safety ground' wire to
mains breaker box. Some current goes into computer motherboard,
through modem, and to earth via phone line. Not all current goes
destructively through computer as trader claims. Large current also
passed through and destroys modem. Why? All current did not get
conducted by a high impedance safety ground wire that is at 2000
volts.
Decades ago an adjacent protector earthed a surge destructively
through powered off computers - damage proven by following and
replacing all damaged ICs. Another unbiased source - Martzloff in an
IEEE paper - also warns of same damage "even when or perhaps because,
surge protective devices are present at the point of connection of
appliances. "
Joseph Meehan - repeatedly posted were links to non-commercial
authoritative sites such as Martzloff and IEEE. Later you ask for non-
commercial citations. Why do you keep asking that question after
information is provided? Why the standard denials?
trader also does it again. He assumes safety ground wire is a
perfect conductor because he does not understand impedance. As an
electrician, he confuses resistance with impedance. The non-
commercial page 42 Figure 8 shows 2000 volts 'end to end' on that
wire. Why? Excessive wire impedance. Because it is not a 'less than
10 foot' earthing connection, too much wire impedance and 2000
destructive volts. trader remains in denial mode?
trader cannot grasp this concept: wire impedance. trader - why is
the protector in Figure 8 at 2000 and 8000 volts? Why ignore
excessive wire impedance even in this 'mike holt' provided figure?
But again I say to you - learn about wire impedance. Look at figure
8: why a TV is at 8000 volts. Wire to earth ground is too long, too
many sharp bends, splices, etc. Too much impedance means ineffective
earthing. So where does that 8000 volts find earth ground?
Destructively via an adjacent TV. The non-commercial page 42 Figure 8
again demonstrates Martzloff's problem with plug-in protectors - that
can even contribute to appliance damage.
Surges can also generate from inside the home. For instance,
appliances such as furnaces, air conditioners and vacuum cleaners
Same myth was written by an English major in HowStuffWorks. The
vacuum cleaner is so destructive that everyone troops to hardware
stores weekly to replace clock radios and digital clocks? Oh.
Internal protection makes vacuum cleaner 'surges' irrelevant?
Exactly. Trader repeatedly posts that claim and I repeatedly reply
with this example. Notice how electronics inside a microwave oven are
routinely damaged by the furnace? What protected appliances not on a
surge protector? Internal protection that was industry standard even
30+ years ago. Why does trader not know of this internal protection
even inside HDTVs?
But trader says we are all replacing dimmer switches weekly due to
damage created by refrigerators. Appliances must contain internal
protection. Anything that plug-in protector might accomplish is
already inside the appliance. Internal appliance protection demands
one properly earth a 'whole house' protector so that internal
protection is not overwhelmed.
Why does trader deny that internal protection? Trader assumes that
protectors fail or vaporize to provide protection. He was provided
MOV datasheets that say protectors must not fail. And yet he remains
fixated on this 'vaporize' concept. Effective protectors earth
lightning strikes and must remain functional. Just another reason why
'whole house' protectors are properly sized.
Meanwhile a surge arrives at an HDTV and surge protector. The
protector is so grossly undersized as to disconnect as fast as
possible - to smoke. HDTV is then left to fend for itself. No
problem. HDTV has sufficient internal protection. But the naïve
proclaim "a surge protector sacrificed itself to protect my TV".
Wrong. A surge too small to harm an HDTV struck both TV and surge
protector simultaneously. Only the surge protector was grossly
undersized - vaporized - so that the naïve will promote more sales.
Surge protectors contain MOVs. MOVS are rated for 8/20 and 10/1000
microsecond waveforms. Why these waveforms? Because MOVs are
designed for a surge that creates those waveforms: Lightning. Surge
protection is installed so that lightning does not do damage.
Protection that also makes other transients irrelevant.
But again, trader denies protection already inside appliances - as
he denies wire impedance and that 2000 volts - as he denies protectors
are for lightning protection - as he denies how an adjacent protector
can even contribute to appliance damage.
Protectors without that short ('less than 10 foot') connection to a
single point earth ground cannot provide protection. A protector is
only a connecting device to earth ground. That 'magic box' does not
stop what 3 miles of sky could not.
Wire impedance is why all telcos install Central Office protectors
ON an earth ground AND up to 50 meters distant from electronics. Wire
impedance is why Orange County solved surge damage by enhancing the
earthing system; did not install plug-in protectors:
http://www.psihq.com/AllCopper.htm
Wire impedance is why the Air Force requires protector located "as
soon as practical where the conductor enters the interior of the
facility." Surge protection is about low impedance and a single
point earth ground. Effective protectors make that dedicated 'less
than 10 foot' connection to earth. Plug-in protectors do not make
that connection AND do not claim to protect from the type of surges
that typically cause damage. What do the typically destructive surges
do? Come down any or all wires seeking earth ground, destructively,
through appliances. Surge overwhelms protection already inside all
appliances. Surge must be earthed before it can enter a building.
Effective protectors make the typically destructive surge (which not
created by vacuum cleaners) irrelevant. That means a short connection
to earth. No earth ground means no effective protection.