Re: do I need a surge protector?
- From: "Tom in Macon" <TomMacon@xxxxxxxxxx>
- Date: Sat, 24 Feb 2007 12:39:00 -0500
"w_tom" <w_tom1@xxxxxxx> wrote in message
On Feb 24, 8:38 am, Sam Spade <s...@xxxxxxxxxxxx> wrote:Just wondering why you don't consider the ground wire in an outlet as
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
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
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
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