Re: what is the differences between whole house surge protectors?
- From: "Gary" <satmaverick@xxxxxxxxxxx>
- Date: Tue, 3 Mar 2009 12:58:24 -0700
My bad. Here you go...
http://www2.sea.siemens.com/Products/Residential-Electrical/Product/Surge-Protection/Protection_at_the_Point_of_Entry.htm?languagecode=en
"bud--" <remove.budnews@xxxxxxx> wrote in message
news:393f0$49ad5c39$cde8d5a5$9571@xxxxxxxxxxxxxxxx
John Grabowski wrote:
"westom" <westom1@xxxxxxxxx> wrote in message
news:3b6c14b4-bf2e-471c-ac59-cbe89e9bbe6c@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Mar 2, 1:09 pm, "Gary" <satmaver...@xxxxxxxxxxx> wrote:
I want to put a whole house surge protector in my breaker box. It is a
Siemens
and I can use either a QSA2020 or a QSA2020TVSS. One is whole house
secondary surge arrestor and one is a transient voltage surge
suppressor.
If you would have provided links to information for the suppressors I
would have looked. It is not reasonable to expect everyone to find your
information.
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.
Of course, the short connection to earth ground makes a protector
effective. No earth ground means no effective protection. Protectors
do not provide protection.
w has a religious belief (immune from challenge) that surge protection
must directly use earthing. Much of what he writes here is to say plug-in
suppressors, which do not have his 10 foot path to earth, do not work.
Unfortunately for w 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).
Verify that breaker box earthing both meets and exceeds post 1990
codes and that all incoming utility 'whole house' protectors (such as
the required one provided free by the telco) also make a short
connection to same earthing.
Not just the same earthing. The length of the ground wire connecting phone
and cable entry protectors to the ground at the power service should be
minimized. Even with a good earth connection, a strong surge can lift the
"ground" at the house thousands of volts above "absolute" ground
potential. Much of the protection is actually keeping the power and phone
and cable wires at the same elevated potential. That requires a short
interconnection. A ground wire that is too long is illustrated in the IEEE
guide starting pdf page 40.
The NIST guide, citing US insurance information, suggests most equipment
is damaged by high voltage between power and phone or cable wires.
(If you are using a plug-in suppressor, to limit voltage between wires all
interconnected equipment needs to be connected to the same plug-in
suppressor. And external wires, like phone and cable, also need to go
through the same suppressor.)
One 'whole house' protector is the least expensive and best
protector if properly earthed.
Service panel suppressors are certainly 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. To limit the voltage you need a *short*
wire connecting the cable/phone entrance protectors to the ground at the
power service.
========================
*Exactly. If you have no ground those surge suppressors can be dangerous
during a lightning strike. They will absorb the current, but without a
place to dissipate it they could explode.
Actually, the worse the earth connection is the lower the energy the
suppressor will absorb. The energy absorbed is the voltage across the
suppressor (clamp voltage) times the current times the time. The voltage
and time are essentially the same. The current will, in theory, decrease
as the resistance to earth goes up.
Neither service panel or plug-in suppressors protect by absorbing energy.
But both absorb some energy in the process of protecting.
http://www.mrelectrician.tv/questions&answers.html#ground
One error in this source is that plug-in suppressors work by earthing a
surge through a receptacle ground wire. They don't. They work primarily by
clamping the voltage between all wires at the suppressor.
--
bud--
.
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