Re: Ground Rod For House ?

w_tom wrote: 
  An example demonstrates the earthing problem.  A 12 AWG wire
from wall receptacle maybe 50 feet back to mains box has less
than 0.2 ohms resistance.  That same wire would have something
like 120 ohms impedance.  Lets say a tiny 100 amp transient
seeks earth ground via that 50 foot wire.  Therefore a wall
receptacle - and adjacent electronics - will be at something
less than 12,000 volts.  Will that transient seek earth via
that safety ground wire?  Of course not.  It will also seek
other and destructive paths via adjacent electronics.

  Wire length is but one reason why a wall receptacle safety
ground is not sufficient as earth ground.  Also explains why
plug-in protectors are so ineffective.

I never talked about branch ckts and don't want to start now. If I did I would want a citation for 120 ohms.
Impedance of ground rod and water pipe would be relevant.

Concrete encased grounding (Ufer grounds) were so well
proven even before WWII as to even protect munitions from
direct lightning strikes. If water pipe earthing was so
effective, then why do they implement Ufer grounding even in
buildings with water pipe grounds?

Perhaps because a supplementary ground is required for a water pipe because it may be replaced by plastic and ground rods are way worse than either. Not obvious who "they" are. If it is gfretwell, in a current thread he says the gound conductivity near him is very bad. Sounds like the Ufer is a foundation ring. An unrelated video tape shows driving a 10' rod in Florida with a water table about 3' down, connecting 120V and getting a current of about 1.5A (implies 80 ohms ground resistance).

Halo grounds are but 
another way of improved earthing.

Probably mean ground ring in NEC. Phaser uses halo (in the air) and it isn't what you want.

-----------
I actually only planned to respond to your citations in response to me and pop:
>
> Cinergy demonstrates how to solve earthing problems created
> when utilities arrive at wrong locations. A problem often
> created by service installers or builders who still have not
> learned about proper earthing:
> http://www.cinergy.com/surge/ttip08.htm
>
Cinergy in effect talks about a common ground reference which I have emphasized several times. We probably substantialy, but not entirely agree on this. Nothing on water pipes and ground rods which we don't agree on.

> Where does the human start to
> eliminate transistor damage?  Earth ground as even
> demonstrated in that previous  www.tvtower.com  citation.

I have no idea what at that site is relevant

> Polyphaser
> discusses THE most critical component in protection - earth
> ground:
>   http://www.polyphaser.com/ppc_ptd_home.aspx

The most consistent protection in the papers is having a common ground reference for power and signal. They talk about using ground rods only to ground towers - which constitute large lightning rods. No one protects their house from direct lightning strikes unless they install lightning rods/air terminals. Most of the info is specific to lightning, towers and antenna coax - not particularly relevant to grounding elsewhere. If you are going to cite it you should pick out the relevant papers, if any.

bud--
.

Relevant Pages

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