Re: Driving a seperate ground rod
- From: w_tom <w_tom1@xxxxxxx>
- Date: Sat, 28 Jul 2007 22:57:00 -0700
On Jul 27, 3:00 pm, Terry <kilow...@xxxxxxxxxxx> wrote:
I think the electrical service in my house is adequate, but I suspect
that my copper pipe is not.
Thanks for every one's comments.
Boy those typos were bad. :)
Your post implies earthing to eliminate surge damage. Earthing must
answer to many masters. For example, it is required by code for
numerous human safety reasons. Any fault must trip a circuit
breaker. Transformer neutral failure will not cause excessive
currents via gas meter and resulting explosion. Etc.
Earthing for transistor protection means earthing also must exceed
post 1990 code requirements. Code only addresses human safety which
is why water pipe earthing is no longer sufficient and does not meet
post 1990 code requirements. For transistor protection, that same
earthing also must exceed code requirements.
Code says breaker box (with main disconnect) must be earthed (some
jurisdictions want this earthing in the meter panel). For transistor
protection, that earth must also be less than 10 feet, no sharp wire
bends, no splices, everything earthed to one electrode, etc. Code
does not demand any of this. But to eliminate motherboard surge
damage, these are some additional requirements for earthing.
Still that is not sufficient. For example AC electric service has
three wires. If any one wire is not earthed, then modem damage can
result. But how is AC electric delivered when all three wires are
earthed? Neutral wire must be earthed directly. But other 'hot
wires' must make that 'less than 10 foot' connection via a protector.
Notice what a protector does. It does not (and does not claim) to
provide protection. The protector is simply a connecting device to
earth ground. Nothing more. A protector without that earth ground
many even earth surges destructively via adjacent appliances (Page 42
Figure 8 in http://omegaps.com/Lightning%20Guide_FINALpublishedversion_May051.pdf).
A protector that makes that 'less than 10 foot' earthing connection
means 1) surges will not enter a building to seek earth ground
destructively via modem and motherboards, 2) protection inside all
other household appliances is not overwhelmed, and 3) everything in
the building human safety appliances (ie smoke detectors, GFCIs) also
are protected.
Earth ground is the protection. Protection improves when a single
point earth ground is even made better (ie 'less than 10 foot
connection). Most important - every incoming wire in every cable must
connect 'less than 10 feet' to that earth ground before entering the
building. Your telco does that so their switching computer connected
to overhead wires all over town is never damaged. The technique is
that effective and that well proven. Again, the protector is only a
connecting device to protection. Better protection means better
earthing.
Did you know the telco installs a 'whole house' protector on you
phone line? Why? Because that protector is so effective and costs
massively less compared to a plug-in protector. But again, if a
protector does not make a connection to earthing, then the enter
protection system is compromised. - like a water pipe replaced in PVC.
Cable TV does not need a protector. Why? Protectors do not provide
protection. Cable is protected by a $2 ground block and a wire to
the earthing electrode. Protectors would only diminish that
protection - but enrich some manufacturers. What defines quality of
that protection system? Earth ground. Better earthing means less
surge will enter a building to overwhelm protection already inside all
household appliances.
Above is the technology. If you learn the technology, then Bud's
people don't profit by selling protectors without earthing. Page 42
Figure 8: TV damaged by 8000 volts because an expensive plug-in
protector was too far from earth ground (basically had no earthing),
plug-in protector was too close to appliance, AND earthing system
violated principles cited above.
How to identify the ineffective protector? It has no dedicated wire
to make that 'less than 10 foot' earthing connection AND manufacturer
avoids all discussion about earthing. Therein defines where that
ground rod must be located and how everything connects to it.
Do you run the ground wire from breaker box, up over foundation, and
down to earth ground rod? Yes to meet code. Not sufficient to
protect computers. The ground wire over foundation would have too
many sharp bends, be too long, and would be bundled with other non-
earthing wires. Ground wire bundled with other wires may even induce
surges on those other wires. That ground wire must pass through
foundation and down to earthing electrode. Wire must be shorter, less
bends, separated, etc.
Concepts that define where an earthing rod is located and how
connections are made are in comp.sys.mac.comm on 4 Jul 2007 entitled
"DSL speed" at
http://tinyurl.com/2gbgef
What happens when a plug-in protector has no dedicated earthing wire
- cannot make that 'less than 10 foot' connection? Page 42 Figure 8
is one example: the surge finds another path to earth - 8000 volts
destructively - via the adjacent TV. TV earthed a surge because it
was not earthed where wire entered the building. No earth ground
means no effective protection.
.
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