On Thu, 05 Jan 2017 04:56:33 -0000, wrote:

On Wed, 04 Jan 2017 20:37:51 -0500, wrote:

On Thu, 05 Jan 2017 01:24:08 -0000, "James Wilkinson Sword"
wrote:

On Thu, 05 Jan 2017 01:13:23 -0000, Dean Hoffman wrote:

On 1/4/17 6:32 PM, James Wilkinson Sword wrote:

Some cut.

I guess one doesn't test earth grounding with a regular ohm meter.

You guess?

The instructor at one of my code refresher classes asked once if
anyone had
the correct type of tester. No one did out of at least 50
electricians. Earth grounding
is primarily for damage from lightning. He also had a diagram showing
how little current would flow through the earth if a well motor had a
short to the frame. The resistance was so high that there was no way
even a tiny fuse would blow if there was a short.
This is from the meter maker Fluke:
http://support.fluke.com/find-sales/Download/Asset/2633834_6115_ENG_A_W.PDF


"A good grounding resistance is 5 ohms or less" - well since I got 20
MOhms, I guess that isn't grounded.

So did you use an actual ground tester or a volt/ohm meter? It
sure seems odd that
your results don't match Mr. Ufer's and bunches of people after him.
An article in Electrical Contractor magazine says Ufer's grounding
electrodes kept the resistance at 2-5 ohms over a 20 year period.
http://www.ecmag.com/section/codes-standards/what-ufer-ground

Resistance is resistance. Concrete does NOT conduct. WATER conducts. Concrete is a porous material which may or may not contain water. The floor of your house should never contain water, or you have BIG problems, way above a possibility of shock.

Stop the presses, some naked scotsman has debunked 100 years of
electrical science. Your Nobel prize is in the mail sir.
Concrete without water in it isn't concrete. The lime in portland
cement is hydrated. Don'rt believe me? What happens if you heat
concrete quickly? It explodes from the steam poressure created by the
entrained moisture in the concrete - the hydration. That's what
refractory cement is made for, and the reason it exists.

from a concrete information site :

When water is added to cement, each of the compounds undergoes
hydration and contributes to the final concrete product. Only the
calcium silicates contribute to strength. Tricalcium silicate is
responsible for most of the early strength (first 7 days). Dicalcium
silicate, which reacts more slowly, contributes only to the strength
at later times. Tricalcium silicate will be discussed in the greatest
detail.

The equation for the hydration of tricalcium silicate is given by:

Tricalcium silicate + Water---Calcium silicate hydrate+Calcium
hydroxide + heat

2 Ca3SiO5 + 7 H2O --- 3 CaO.2SiO2.4H2O + 3 Ca(OH)2 + 173.6kJ

Upon the addition of water, tricalcium silicate rapidly reacts to
release calcium ions, hydroxide ions, and a large amount of heat. The
pH quickly rises to over 12 because of the release of alkaline
hydroxide (OH-) ions. This initial hydrolysis slows down quickly after
it starts resulting in a decrease in heat evolved.

The reaction slowly continues producing calcium and hydroxide ions
until the system becomes saturated. Once this occurs, the calcium
hydroxide starts to crystallize. Simultaneously, calcium silicate
hydrate begins to form. Ions precipitate out of solution accelerating
the reaction of tricalcium silicate to calcium and hydroxide ions. (Le
Chatlier's principle). The evolution of heat is then dramatically
increased.

The formation of the calcium hydroxide and calcium silicate hydrate
crystals provide "seeds" upon which more calcium silicate hydrate can
form. The calcium silicate hydrate crystals grow thicker making it
more difficult for water molecules to reach the unhydrated tricalcium
silicate. The speed of the reaction is now controlled by the rate at
which water molecules diffuse through the calcium silicate hydrate
coating. This coating thickens over time causing the production of
calcium silicate hydrate to become slower and slower.

Funny how it doesn't conduct then. Show me a video of dry concrete conducting electricity.

--
What do lawyers and sperm have in common?
1 in 50 million has a chance of becoming a human being.