westom wrote:

The best information on surges and surge protection I have seen is at:
http://www.mikeholt.com/files/PDF/LightningGuide_FINALpublishedversion_May051.pdf
- "How to protect your house and its contents from lightning: IEEE guide
for surge protection of equipment connected to AC power and
communication circuits" published by the IEEE in 2005 (the IEEE is the
major organization of electrical and electronic engineers in the US).
And also:
http://www.nist.gov/public_affairs/practiceguides/surgesfnl.pdf
- "NIST recommended practice guide: Surges Happen!: how to protect the
appliances in your home" published by the US National Institute of
Standards and Technology in 2001

The IEEE guide is aimed at those with some technical background. The
NIST guide is aimed at the unwashed masses.

MOVs in service panel and plug-in suppressors are very effective at
limiting the voltage from a surge, which is very short duration, even if
it involves thousands of amps. Crossed power lines are far too long a
duration and will rapidly burn out MOVs. The author of the NIST guide
has written "in fact, the major cause of [surge suppressor] failures is
a temporary overvoltage, rather than an unusually large surge." A few
plug-in suppressors will disconnect on overvoltage, or a UPS may go to
backup and protect connected equipment.

Cable TV
is earthed directly - no protector required.

Ho-hum - the usual drivel back again.

Doesn't need a protector? The IEEE guide says "there is no requirement
to limit the voltage developed between the core and the sheath. .... The
only voltage limit is the breakdown of the F connectors, typically ~2–4
kV." And "there is obviously the possibility of damage to TV tuners and
cable modems from the very high voltages that can be developed,
especially from nearby lightning." (A plug-in suppressor will limit the
voltage from core to shield.)

Remember what a surge proetctor does. Diverts energy to be
harmlessly dissipated into earth. If ground via the safety ground
wire inside romex, well, that wire also violates most every above
requirement which is why 'point of use' protectors have no earthing.

w_ has a religious belief (immune from challenge) that surge protection
must directly use earthing. Thus in his view plug-in suppressors (which
are not well earthed) can not possibly work. The IEEE guide explains
plug-in suppressors work by CLAMPING (limiting) the voltage on all wires
(signal and power) to the common ground at the suppressor. Plug-in
suppressors do not work primarily by earthing (or stopping or
absorbing). The guide explains earthing occurs elsewhere. (Read the
guide starting pdf page 40).

Note that all interconnected equipment needs to be connected to the same
plug-in suppressor, or interconnecting wires need to go through the
suppressor. External connections, like phone, also need to go through
the suppressor. Connecting all wiring through the suppressor prevents
damaging voltages between power and signal wires.

The NIST guide, using US insurance information, suggests that most
equipment damage is from high voltage between power and phone/cable wires.

Which is why 'point of use' protectors do not even claim to protect
from the type of surges that are typically destructive.

Complete nonsense.

Both the IEEE and NIST guides say plug-in suppressors are effective.

Since a surge
protector is defined by quality of its earthing, then additional
earthing would make an effective protector even better.

If you have a surge-produced current to earth of 1,000A with a very good
resistance to earth of 10 ohms, the potential of the power "ground" at
the house will rise 10,000V above "absolute" earth potential. Much of
the "protection" is that power and phone and cable wires rise together.
That requires a short ground wire from the cable and phone entry
protectors to the "ground" at the power service. A ground wire that is
too long is illustrated in the IEEE guide starting pdf page 40.

The author of the NIST guide 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."

Type of surge that typically destroys
appliances is either earthed (dissipated harmlessly in earth) before
entering a building.

Service panel suppressors are a good idea.
But from the NIST guide:
"Q - Will a surge protector installed at the service entrance be
sufficient for the whole house?
A - There are two answers to than question: Yes for one-link appliances
[electronic equipment], No for two-link appliances [equipment connected
to power AND phone or cable or....]. Since most homes today have some
kind of two-link appliances, the prudent answer to the question would be
NO - but that does not mean that a surge protector installed at the
service entrance is useless."

Service panel suppressors do not prevent high voltages from developing
between power and signal wires.

A refrigerator, a "one link appliance", would likely be protected by a
service panel suppressor.


For real science read the IEEE and NIST guides. Both say plug-in
suppressors are effective.

Then read w's sources that say plug-in suppressors do NOT work. There
are none.

w can't even answer simple questions:
- Why do the only 2 examples of protection in the IEEE guide use plug-in
suppressors?
- Why does the NIST guide says plug-in suppressors are "the easiest
solution"?
- Why does the NIST guide say "One effective solution is to have the
consumer install" a multiport plug-in suppressor?

--
bud--