On Thu, 05 Jan 2017 01:37:51 -0000, 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.

I'm using common sense. You're completely misinterpreting what you read on the internet.

--
Why is bra singular and panties plural?

On Thu, 05 Jan 2017 01:38:07 -0000, "James Wilkinson Sword"
wrote:

On Thu, 05 Jan 2017 01:32:03 -0000, wrote:

On Thu, 05 Jan 2017 00:13:04 -0000, "James Wilkinson Sword"
wrote:

On Thu, 05 Jan 2017 00:05:58 -0000, wrote:

On Wed, 04 Jan 2017 22:22:05 -0000, "James Wilkinson Sword"
wrote:

On Wed, 04 Jan 2017 22:14:30 -0000, wrote:

On Wed, 04 Jan 2017 21:11:44 -0000, "James Wilkinson Sword"
wrote:

On Wed, 04 Jan 2017 21:04:15 -0000, wrote:

On Wed, 04 Jan 2017 17:58:12 -0000, "James Wilkinson Sword"
wrote:

Somebody in one of these two groups recently said that a concrete based house means you're earthed. Concrete is a bloody good insulator!

Not really true, particularly if it is damp

If your floor is damp all the way through, you have bigger problems.

Concrete floors are for garages, houses should have wood floors suspended above the ground. What century is the USA living in?

One where we have not solved the termite,

Chemicals are your friend.

Fine when they work and don't migrate to the ground water.

Not my problem.

hurricane and tornado problems?

Those tend to affect walls and roofs.

If your floor is off the ground, it will just be part of the debris
field when the wind gets up under it.

If the walls are gone, why do you care about your floor?

Under a decent building code they will all stand or blow away
together.
The roof is continuously tied through the walls to the foundation
In a concrete block building that will be continuous rebar from the
foundation to the poured tie beam on the top of the wall, then
strapped to the roof trusses. A typical 1800 sq/ft house will have
almost 100,000 pounds of uplift protection at the roof.

I see. We don't have so much wind here, so my next question is, why are modern houses in the UK starting to have concrete foundations like yours? Old ones, you go under the floor, you can crawl around on dirt and fix the pipes and wires. New ones, you can't get down, it's just solid.

Maybe they think global warming is going to bring you tropical weather
some day. Honestly most of the US does not really have an effective
wind code either but as people start wondering why a summer squall or
dust devil blows their houses to smithereens and a Cat 1 or even 2
here does minimal damage to newer houses here, they start to ponder
why. Most of the hurricane damage pictures you see from Florida is 50
year old homes or, more likely trailers.
I suppose Florida building codes may spread, if for no other reason
that the insurance companies will push them.
I know when I was building in Maryland, the main force people thought
about was gravity with little more than a passing glance at wind
pressure (maybe built to 60-70 MPH) and nothing at all about uplift.
I am in the 150 MPH zone.

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.

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.

Not that well, it is whatever salts and impurities in it that do.



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.

Dean Hoffman wrote:
On 1/4/17 2:00 PM, James Wilkinson Sword wrote:

It was more about getting an electric shock by standing on the floor
of your house while touching something live. This was suggested by
someone recently as being a danger. I just measured some concrete
to make sure I wasn't being ignorant, and it was off the scale
(20MOhms)

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


My house is on a slab and I get five volt tingle from the taps when I am
in the shower.
I suspect that when it was built they did not bond the steel mesh to
earth, which they are supposed to do now.

James Wilkinson Sword wrote:
Resistance is resistance. Concrete does NOT conduct. WATER conducts. Concrete

Not really (water that is), pure water is a very poor conductor. It's the
impurities in water that make it a reasonable coductor but even tap
water isn't that good.

--
Chris Green
·

Chris Green wrote:
James Wilkinson Sword wrote:
Resistance is resistance. Concrete does NOT conduct. WATER conducts. Concrete

Not really (water that is), pure water is a very poor conductor. It's the
impurities in water that make it a reasonable coductor but even tap
water isn't that good.

Is there an echo in here?

On Wed, 4 Jan 2017 16:02:42 -0500
burfordTjustice wrote:

On Wed, 04 Jan 2017 20:00:22 -0000
"James Wilkinson Sword" wrote:

On Wed, 04 Jan 2017 19:13:21 -0000, mike wrote:

On 1/4/2017 10:48 AM, burfordTjustice wrote:
On Wed, 04 Jan 2017 10:42:34 -0800
mike wrote:

On 1/4/2017 9:58 AM, James Wilkinson Sword wrote:
Somebody in one of these two groups recently said that a
concrete based house means you're earthed. Concrete is a
bloody good insulator!

Sorry, can't find the post it was mentioned in.

Can't help with a link, but I recently replaced my water main
with PEX. That broke the ground to the house and wouldn't pass
inspection. Long story short, research indicated that using
rebar in concrete was a trend in establishing a safety ground.
Apparently, there's enough conductive salt and water in concrete
to make it work, as long as the concrete sits on the ground and
you're not in the desert. Contact resistance is high, but
there's a lot of area.

I followed the code and installed two ground rods.
I did some impedance measurements between the rods and the
electrical system ground (before connecting) and determined that
the "grounding" was insufficient to do anything more than
dissipate static electricity, but the
inspector liked it.
I'd guess that hooking to the rebar is at least as good.


"James Wilkinson Sword" is in the UK...different rules
Question wasn't about rules.
Was about concrete as a ground. Unlikely it's much different in
the UK.

It was more about getting an electric shock by standing on the floor
of your house while touching something live. This was suggested by
someone recently as being a danger. I just measured some concrete
to make sure I wasn't being ignorant, and it was off the scale
(20MOhms)


LOL Please post a picture of you taking the measurement.

Well?

On Wednesday, January 4, 2017 at 8:24:20 PM UTC-5, 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.

--
"VAT is a simple tax..." -- Anthony Barber, Chancellor of the Exchequer on the introduction of VAT on April Fool's Day in 1973.

http://www.esgroundingsolutions.com/...ng-electrodes/

Ufer Ground or Concrete Encased Electrodes

Originally, Ufer grounds were copper electrodes encased in the concrete surrounding ammunition bunkers. In todays terminology, Ufer grounds consist of any concrete-encased electrode, such as the rebar in a building foundation, when used for grounding, or a wire or wire mesh in concrete.

Concrete Encased Electrode

The National Electric Code requires that Concrete Encased Electrodes use a minimum No. 4 AWG copper wire at least 20 feet in length and encased in at least 2 inches of concrete. The advantages of concrete encased electrodes are that they dramatically increase the surface area and degree of contact with the surrounding soil. However, the zone of influence is not increased, therefore the resistance to ground is typically only slightly lower than the wire would be without the concrete.

Concrete encased electrodes also have some significant disadvantages. When an electrical fault occurs, the electric current must flow through the concrete into the earth. Concrete, by nature retains a lot of water, which rises in temperature as the electricity flows through the concrete. If the extent of the electrode is not sufficiently great for the total current flowing, the boiling point of the water may be reached, resulting in an explosive conversion of water into steam. Many concrete encased electrodes have been destroyed after receiving relatively small electrical faults. Once the concrete cracks apart and falls away from the conductor, the concrete pieces act as a shield preventing the copper wire from contacting the surrounding soil, resulting in a dramatic increase in the resistance-to-ground of the electrode.

Ufer Ground or Building Foundations

Ufer Grounds or building foundations may be used provided that the concrete is in direct contact with the earth (no plastic moisture barriers), that rebar is at least 0.500 inches in diameter and that there is a direct metallic connection from the service ground to the rebar buried inside the concrete.



If you bothered to look at your own country's codes, you'd see
that Ufers are one of the allowed types of grounding in the UK.

https://books.google.com/books?id=-1...-02-01&f=false

"Handbook of the Wiring Regulations" (UK)
Based on BS 7671 2001 edition

It's page C2/15, they show 7 types of allowed earth grounds,
two of the 7 are metal electrodes embedded in concrete.

But then you say codes don't matter and you've demonstrated
that you're one of the village idiot trolls, so I'm sure
that won't change anything either.

On Thursday, January 5, 2017 at 9:38:01 AM UTC-5, trader_4 wrote:
On Wednesday, January 4, 2017 at 8:24:20 PM UTC-5, 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.

--
"VAT is a simple tax..." -- Anthony Barber, Chancellor of the Exchequer on the introduction of VAT on April Fool's Day in 1973.

http://www.esgroundingsolutions.com/...ng-electrodes/

Ufer Ground or Concrete Encased Electrodes

Originally, Ufer grounds were copper electrodes encased in the concrete surrounding ammunition bunkers. In todays terminology, Ufer grounds consist of any concrete-encased electrode, such as the rebar in a building foundation, when used for grounding, or a wire or wire mesh in concrete.

Concrete Encased Electrode

The National Electric Code requires that Concrete Encased Electrodes use a minimum No. 4 AWG copper wire at least 20 feet in length and encased in at least 2 inches of concrete. The advantages of concrete encased electrodes are that they dramatically increase the surface area and degree of contact with the surrounding soil. However, the zone of influence is not increased, therefore the resistance to ground is typically only slightly lower than the wire would be without the concrete.

Concrete encased electrodes also have some significant disadvantages. When an electrical fault occurs, the electric current must flow through the concrete into the earth. Concrete, by nature retains a lot of water, which rises in temperature as the electricity flows through the concrete. If the extent of the electrode is not sufficiently great for the total current flowing, the boiling point of the water may be reached, resulting in an explosive conversion of water into steam. Many concrete encased electrodes have been destroyed after receiving relatively small electrical faults. Once the concrete cracks apart and falls away from the conductor, the concrete pieces act as a shield preventing the copper wire from contacting the surrounding soil, resulting in a dramatic increase in the resistance-to-ground of the electrode.

Ufer Ground or Building Foundations

Ufer Grounds or building foundations may be used provided that the concrete is in direct contact with the earth (no plastic moisture barriers), that rebar is at least 0.500 inches in diameter and that there is a direct metallic connection from the service ground to the rebar buried inside the concrete.



If you bothered to look at your own country's codes, you'd see
that Ufers are one of the allowed types of grounding in the UK.

https://books.google.com/books?id=-1...-02-01&f=false

"Handbook of the Wiring Regulations" (UK)
Based on BS 7671 2001 edition

It's page C2/15, they show 7 types of allowed earth grounds,
two of the 7 are metal electrodes embedded in concrete.

But then you say codes don't matter and you've demonstrated
that you're one of the village idiot trolls, so I'm sure
that won't change anything either.

It's not just that he believes that "codes" don't apply to the owner of
the building, there is another problem with your explanation:

"Concrete, by nature retains a lot of water..."

The only time the water in concrete is an issue is if it rains a lot. Go
ahead, ask him. ;-)

"Only if the concrete stays wet. Which won't happen unless it rains a lot."

See? He said it. It must be true.

On Thursday, January 5, 2017 at 3:01:37 AM UTC-5, F Murtz wrote:
Dean Hoffman wrote:
On 1/4/17 2:00 PM, James Wilkinson Sword wrote:

It was more about getting an electric shock by standing on the floor
of your house while touching something live. This was suggested by
someone recently as being a danger. I just measured some concrete
to make sure I wasn't being ignorant, and it was off the scale
(20MOhms)

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


My house is on a slab and I get five volt tingle from the taps when I am
in the shower.
I suspect that when it was built they did not bond the steel mesh to
earth, which they are supposed to do now.

There is something wrong with the bonding and/or grounding, and it
shouldn't be hard to identify and correct. I'd get it fixed before
something bad happens.

On Thu, 5 Jan 2017 19:09:46 +1100, F Murtz
wrote:

My house is on a slab and I get five volt tingle from the taps when I am
in the shower.
I suspect that when it was built they did not bond the steel mesh to
earth, which they are supposed to do now.

Check, or have an electrician your grounding electrode system. Also be
sure metal piping is bonded around any plastic sections, water
softener and the water heater.

Two separate ideas being debated here.

1. Ufer grounding as an appropriate or legal method of grounding your system.

2. Concrete floors considered to be at ground potential.

For the latter, I have always been told that you must consider a concrete floor to be at ground, and therefore refrain from touching any hot wires.

I have not attempted to measure that myself and don't know the source of the claim. But I've seen it in a number of electrical safety classes, so if it is an urban legend it is a well distributed one.

On Thu, 05 Jan 2017 04:30:02 -0000, wrote:

On Thu, 05 Jan 2017 01:38:07 -0000, "James Wilkinson Sword"
wrote:

On Thu, 05 Jan 2017 01:32:03 -0000, wrote:

On Thu, 05 Jan 2017 00:13:04 -0000, "James Wilkinson Sword"
wrote:

On Thu, 05 Jan 2017 00:05:58 -0000, wrote:

On Wed, 04 Jan 2017 22:22:05 -0000, "James Wilkinson Sword"
wrote:

On Wed, 04 Jan 2017 22:14:30 -0000, wrote:

On Wed, 04 Jan 2017 21:11:44 -0000, "James Wilkinson Sword"
wrote:

On Wed, 04 Jan 2017 21:04:15 -0000, wrote:

On Wed, 04 Jan 2017 17:58:12 -0000, "James Wilkinson Sword"
wrote:

Somebody in one of these two groups recently said that a concrete based house means you're earthed. Concrete is a bloody good insulator!

Not really true, particularly if it is damp

If your floor is damp all the way through, you have bigger problems.

Concrete floors are for garages, houses should have wood floors suspended above the ground. What century is the USA living in?

One where we have not solved the termite,

Chemicals are your friend.

Fine when they work and don't migrate to the ground water.

Not my problem.

hurricane and tornado problems?

Those tend to affect walls and roofs.

If your floor is off the ground, it will just be part of the debris
field when the wind gets up under it.

If the walls are gone, why do you care about your floor?

Under a decent building code they will all stand or blow away
together.
The roof is continuously tied through the walls to the foundation
In a concrete block building that will be continuous rebar from the
foundation to the poured tie beam on the top of the wall, then
strapped to the roof trusses. A typical 1800 sq/ft house will have
almost 100,000 pounds of uplift protection at the roof.

I see. We don't have so much wind here, so my next question is, why are modern houses in the UK starting to have concrete foundations like yours? Old ones, you go under the floor, you can crawl around on dirt and fix the pipes and wires. New ones, you can't get down, it's just solid.

Maybe they think global warming is going to bring you tropical weather
some day. Honestly most of the US does not really have an effective
wind code either but as people start wondering why a summer squall or
dust devil blows their houses to smithereens and a Cat 1 or even 2
here does minimal damage to newer houses here, they start to ponder
why. Most of the hurricane damage pictures you see from Florida is 50
year old homes or, more likely trailers.
I suppose Florida building codes may spread, if for no other reason
that the insurance companies will push them.
I know when I was building in Maryland, the main force people thought
about was gravity with little more than a passing glance at wind
pressure (maybe built to 60-70 MPH) and nothing at all about uplift.
I am in the 150 MPH zone.

I thought the general idea in America was to make them NOT wind proof, but easy and cheap to rebuild?

--
You don't appreciate a lot of stuff in school until you get older.
Little things like being spanked every day by a middle-aged woman.
Stuff you pay good money for later in life. -- Elmo Phillips

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.

On Thu, 05 Jan 2017 08:04:42 -0000, F Murtz wrote:

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.

Not that well, it is whatever salts and impurities in it that do.

I never said pure water :-)

--
Statistics show that 25% of all women are on medication for mental illness.
That's scary! It means 75% are running around with no bloody medication at all!!!

On Thu, 05 Jan 2017 10:14:05 -0000, Chris Green wrote:

James Wilkinson Sword wrote:
Resistance is resistance. Concrete does NOT conduct. WATER conducts. Concrete

Not really (water that is), pure water is a very poor conductor. It's the
impurities in water that make it a reasonable coductor but even tap
water isn't that good.

It's very good. Which is why people get shock in swimming pools and baths.

--
A dyslexic man walks into a bra.

James Wilkinson Sword posted for all of us...



Somebody in one of these two groups recently said that a concrete based house means you're earthed. Concrete is a bloody good insulator!

Negative, if one looks at an AM radio station the tower is used as the
antenna. Note a big ceramic insulator between the tower and the foundation.
the is a spark gap on the insulator for lighting. If the transmitter is
active then a non conductive ladder to climb the tower. That is why
maintenance is performed at night because they are off the air.


--
Tekkie

On Thu, 05 Jan 2017 14:37:55 -0000, trader_4 wrote:

On Wednesday, January 4, 2017 at 8:24:20 PM UTC-5, 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.

--
"VAT is a simple tax..." -- Anthony Barber, Chancellor of the Exchequer on the introduction of VAT on April Fool's Day in 1973.

http://www.esgroundingsolutions.com/...ng-electrodes/

Ufer Ground or Concrete Encased Electrodes

Originally, Ufer grounds were copper electrodes encased in the concrete surrounding ammunition bunkers. In todays terminology, Ufer grounds consist of any concrete-encased electrode, such as the rebar in a building foundation, when used for grounding, or a wire or wire mesh in concrete.

Concrete Encased Electrode

The National Electric Code requires that Concrete Encased Electrodes use a minimum No. 4 AWG copper wire at least 20 feet in length and encased in at least 2 inches of concrete. The advantages of concrete encased electrodes are that they dramatically increase the surface area and degree of contact with the surrounding soil. However, the zone of influence is not increased, therefore the resistance to ground is typically only slightly lower than the wire would be without the concrete.

Concrete encased electrodes also have some significant disadvantages. When an electrical fault occurs, the electric current must flow through the concrete into the earth. Concrete, by nature retains a lot of water, which rises in temperature as the electricity flows through the concrete. If the extent of the electrode is not sufficiently great for the total current flowing, the boiling point of the water may be reached, resulting in an explosive conversion of water into steam. Many concrete encased electrodes have been destroyed after receiving relatively small electrical faults. Once the concrete cracks apart and falls away from the conductor, the concrete pieces act as a shield preventing the copper wire from contacting the surrounding soil, resulting in a dramatic increase in the resistance-to-ground of the electrode.

Ufer Ground or Building Foundations

Ufer Grounds or building foundations may be used provided that the concrete is in direct contact with the earth (no plastic moisture barriers), that rebar is at least 0.500 inches in diameter and that there is a direct metallic connection from the service ground to the rebar buried inside the concrete.



If you bothered to look at your own country's codes, you'd see
that Ufers are one of the allowed types of grounding in the UK.

https://books.google.com/books?id=-1...-02-01&f=false

"Handbook of the Wiring Regulations" (UK)
Based on BS 7671 2001 edition

It's page C2/15, they show 7 types of allowed earth grounds,
two of the 7 are metal electrodes embedded in concrete.

But then you say codes don't matter and you've demonstrated
that you're one of the village idiot trolls, so I'm sure
that won't change anything either.

20 feet deep. How deep is the concrete in your floor? 6 inches?

--
I know you believe you understand what you think I said,
but I'm not sure you realize that what you heard is not
what I meant.

On Thu, 05 Jan 2017 15:06:00 -0000, trader_4 wrote:

On Thursday, January 5, 2017 at 3:01:37 AM UTC-5, F Murtz wrote:
Dean Hoffman wrote:
On 1/4/17 2:00 PM, James Wilkinson Sword wrote:

It was more about getting an electric shock by standing on the floor
of your house while touching something live. This was suggested by
someone recently as being a danger. I just measured some concrete
to make sure I wasn't being ignorant, and it was off the scale
(20MOhms)

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


My house is on a slab and I get five volt tingle from the taps when I am
in the shower.
I suspect that when it was built they did not bond the steel mesh to
earth, which they are supposed to do now.

There is something wrong with the bonding and/or grounding, and it
shouldn't be hard to identify and correct. I'd get it fixed before
something bad happens.

Yes, 5V can be very very nasty....

--
Beating your wife is like keying your own car.

"F Murtz" wrote in message
b.com...
Dean Hoffman wrote:
On 1/4/17 2:00 PM, James Wilkinson Sword wrote:

It was more about getting an electric shock by standing on the floor
of your house while touching something live. This was suggested by
someone recently as being a danger. I just measured some concrete
to make sure I wasn't being ignorant, and it was off the scale
(20MOhms)

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

My house is on a slab

So is mine.

and I get five volt tingle from the taps when I am in the shower.

I don't. What's the detail on the plumbing ? Mine is
soldered copper, mostly but not entirely yorkshire fittings.

I suspect that when it was built they did not bond the steel mesh to
earth,

Very unlikely. I know mine isnt because I did the
mesh and slab myself and I don't get that effect.

which they are supposed to do now.

Gotta cite on that ?

What are you doing hot water wise ?

On Thu, 05 Jan 2017 21:02:28 -0000, "James Wilkinson Sword"
wrote:

20 feet deep. How deep is the concrete in your floor? 6 inches?

The 20 feet is horizontal.

On Thu, 05 Jan 2017 20:57:15 -0000, Tekkie® wrote:

James Wilkinson Sword posted for all of us...



Somebody in one of these two groups recently said that a concrete based house means you're earthed. Concrete is a bloody good insulator!

Negative, if one looks at an AM radio station the tower is used as the
antenna. Note a big ceramic insulator between the tower and the foundation.
the is a spark gap on the insulator for lighting. If the transmitter is
active then a non conductive ladder to climb the tower. That is why
maintenance is performed at night because they are off the air.

The base can get wet.

--
Hipatitis (n): Terminal coolness.

On Thu, 05 Jan 2017 21:20:58 -0000, wrote:

On Thu, 05 Jan 2017 21:02:28 -0000, "James Wilkinson Sword"
wrote:

20 feet deep. How deep is the concrete in your floor? 6 inches?

The 20 feet is horizontal.

If it's not below the water table, no conduction.

--
Snap-off parts, because it's French.

After serious thinking James Wilkinson Sword wrote :
On Thu, 05 Jan 2017 21:20:58 -0000, wrote:

On Thu, 05 Jan 2017 21:02:28 -0000, "James Wilkinson Sword"
wrote:

20 feet deep. How deep is the concrete in your floor? 6 inches?

The 20 feet is horizontal.

If it's not below the water table, no conduction.

All materials conduct, some better than others.

If you touch a hot 120 V wire while standing in socks on your concrete basement
floor or on a deck outside, you WILL get a shock.


It's up to you if you want to call that __conducting__ or not.



m

On Thursday, January 5, 2017 at 12:57:27 PM UTC-5, TimR wrote:
Two separate ideas being debated here.

1. Ufer grounding as an appropriate or legal method of grounding your system.

2. Concrete floors considered to be at ground potential.

For the latter, I have always been told that you must consider a concrete floor to be at ground, and therefore refrain from touching any hot wires.

I have not attempted to measure that myself and don't know the source of the claim. But I've seen it in a number of electrical safety classes, so if it is an urban legend it is a well distributed one.

With regard to the initial claim, that concrete does not conduct,
it's the same issue with both. If concrete did not conduct, a
concrete encased electrode for an earth ground would be useless
and you would not get shocked standing on a concrete floor.

On Friday, January 6, 2017 at 9:29:15 AM UTC-5, wrote:
If you touch a hot 120 V wire while standing in socks on your concrete basement
floor or on a deck outside, you WILL get a shock.


It's up to you if you want to call that __conducting__ or not.



m

I found a reply from OSHA to a question from a corporate safety officer:

Question 2: Would you consider an ungrounded fan, on a dry concrete floor, on grade, in an industrial setting a violation of this specific standard?

Reply: The use of an ungrounded fan situated on a dry concrete floor on grade in an industrial setting will be a violation of the OSHA rule at 1910.304(f)(5)(v)(C)(5), if the fan has exposed non-current-carrying metal parts that can be contacted by employees. Concrete on grade level, because it will absorb moisture from the earth and be a good conductor in direct contact with the earth, is always considered to be at ground potential.

On 04/01/2017 18:48, burfordTjustice wrote:
"James Wilkinson Sword" is in the UK...different rules

And you aren't?

(Oh. Someone's cross posted this lot to a global list as well as the UK one)

On 05/01/2017 00:14, Dean Hoffman wrote:
I guess one doesn't test earth grounding with a regular ohm meter.
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

I like that link.

Page 5 has a table with ground electrode depths ranging between 3 and
1000 meters.

Yes, meters. I'll assume they mean metres, which is well over half a
mile... maybe they do mean a pile of 1000 testers?

Hmm... I wonder what they do mean?

Page 6 says "Just watch your units"

Andy

On Fri, 06 Jan 2017 15:00:04 -0000, trader_4 wrote:

On Thursday, January 5, 2017 at 12:57:27 PM UTC-5, TimR wrote:
Two separate ideas being debated here.

1. Ufer grounding as an appropriate or legal method of grounding your system.

2. Concrete floors considered to be at ground potential.

For the latter, I have always been told that you must consider a concrete floor to be at ground, and therefore refrain from touching any hot wires.

I have not attempted to measure that myself and don't know the source of the claim. But I've seen it in a number of electrical safety classes, so if it is an urban legend it is a well distributed one.

With regard to the initial claim, that concrete does not conduct,
it's the same issue with both. If concrete did not conduct, a
concrete encased electrode for an earth ground would be useless
and you would not get shocked standing on a concrete floor.

You don't. Try it. Or try placing a lightbulb or meter instead of yourself. One end on live, the other end with a steel plate on the concrete floor the same size as your bare feet. Show me a video of this working.

--
Thank you velly much. I'm not Wan King the chef, I'm Fu King the owner.

On Fri, 06 Jan 2017 14:29:12 -0000, wrote:

If you touch a hot 120 V wire while standing in socks on your concrete basement
floor or on a deck outside, you WILL get a shock.


It's up to you if you want to call that __conducting__ or not.

You don't get enough current through a 20MOhm resistance to give you even a tingle.

--
Steve Ryder covering the US Masters: "Ballesteros felt much better today after a 69 yesterday."

On Fri, 06 Jan 2017 01:36:40 -0000, FromTheRafters wrote:

After serious thinking James Wilkinson Sword wrote :
On Thu, 05 Jan 2017 21:20:58 -0000, wrote:

On Thu, 05 Jan 2017 21:02:28 -0000, "James Wilkinson Sword"
wrote:

20 feet deep. How deep is the concrete in your floor? 6 inches?

The 20 feet is horizontal.

If it's not below the water table, no conduction.

All materials conduct, some better than others.

And in this case it's so insignificant it's nothing. Lightning might go through it....

--
Peter is listening to "Hollywood Undead - Turn Out The Lights"

On Fri, 06 Jan 2017 15:56:08 -0000, TimR wrote:

On Friday, January 6, 2017 at 9:29:15 AM UTC-5, wrote:
If you touch a hot 120 V wire while standing in socks on your concrete basement
floor or on a deck outside, you WILL get a shock.


It's up to you if you want to call that __conducting__ or not.



m

I found a reply from OSHA to a question from a corporate safety officer:

Question 2: Would you consider an ungrounded fan, on a dry concrete floor, on grade, in an industrial setting a violation of this specific standard?

Reply: The use of an ungrounded fan situated on a dry concrete floor on grade in an industrial setting will be a violation of the OSHA rule at 1910.304(f)(5)(v)(C)(5), if the fan has exposed non-current-carrying metal parts that can be contacted by employees. Concrete on grade level, because it will absorb moisture from the earth and be a good conductor in direct contact with the earth, is always considered to be at ground potential.

There's something very important right there which backs me up completely:

"because it will absorb moisture from the earth and be a good conductor in direct contact with the earth". So **damp** concrete conducts. I wasn't talking about damp concrete. I was talking about concrete dry enough to be the floor of your home. Do you really walk around on damp floors? What if you lay a carpet?

--
Peter is in the top three most intelligent people -- Ron Tompkins, circa 2013.

On Fri, 06 Jan 2017 21:51:56 -0000, Vir Campestris wrote:

On 04/01/2017 18:48, burfordTjustice wrote:
"James Wilkinson Sword" is in the UK...different rules

And you aren't?

(Oh. Someone's cross posted this lot to a global list as well as the UK one)

Oh how confusing.

--
While taking down the vitals for a soon-to-be mom, I asked how much she weighed.
"I really don't know," she said.
"Well, more or less," I prompted.
"More, I guess," she answered sadly.

On Fri, 06 Jan 2017 21:58:59 -0000, Vir Campestris wrote:

On 05/01/2017 00:14, Dean Hoffman wrote:
I guess one doesn't test earth grounding with a regular ohm meter.
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

I like that link.

Page 5 has a table with ground electrode depths ranging between 3 and
1000 meters.

Yes, meters. I'll assume they mean metres, which is well over half a
mile... maybe they do mean a pile of 1000 testers?

Hmm... I wonder what they do mean?

Page 6 says "Just watch your units"

[crosses legs]

--
While taking down the vitals for a soon-to-be mom, I asked how much she weighed.
"I really don't know," she said.
"Well, more or less," I prompted.
"More, I guess," she answered sadly.

On Saturday, January 7, 2017 at 10:28:15 AM UTC-5, James Wilkinson Sword wrote:
On Fri, 06 Jan 2017 15:56:08 -0000, TimR wrote:

On Friday, January 6, 2017 at 9:29:15 AM UTC-5, wrote:
If you touch a hot 120 V wire while standing in socks on your concrete basement
floor or on a deck outside, you WILL get a shock.


It's up to you if you want to call that __conducting__ or not.



m

I found a reply from OSHA to a question from a corporate safety officer:

Question 2: Would you consider an ungrounded fan, on a dry concrete floor, on grade, in an industrial setting a violation of this specific standard?

Reply: The use of an ungrounded fan situated on a dry concrete floor on grade in an industrial setting will be a violation of the OSHA rule at 1910.304(f)(5)(v)(C)(5), if the fan has exposed non-current-carrying metal parts that can be contacted by employees. Concrete on grade level, because it will absorb moisture from the earth and be a good conductor in direct contact with the earth, is always considered to be at ground potential.

There's something very important right there which backs me up completely:

"because it will absorb moisture from the earth and be a good conductor in direct contact with the earth". So **damp** concrete conducts. I wasn't talking about damp concrete. I was talking about concrete dry enough to be the floor of your home. Do you really walk around on damp floors? What if you lay a carpet?

--
Peter is in the top three most intelligent people -- Ron Tompkins, circa 2013.

So sad that the UK is apparently so poor and backward that they
apparently have bare concrete floors in the living space of most homes.

On Saturday, January 7, 2017 at 10:26:14 AM UTC-5, James Wilkinson Sword wrote:
On Fri, 06 Jan 2017 14:29:12 -0000, wrote:

If you touch a hot 120 V wire while standing in socks on your concrete basement
floor or on a deck outside, you WILL get a shock.


It's up to you if you want to call that __conducting__ or not.

You don't get enough current through a 20MOhm resistance to give you even a tingle.

--



Conducting is not a absolute term, there are various degrees of conducting. Thats why they make Ohm meters.

I just tested in my dry basement. Two bare feet on concrete tested about 50K Ohms. Not enough to light a light bulb, but enough to give a shock.

m

On 1/7/17 9:26 AM, James Wilkinson Sword wrote:
On Fri, 06 Jan 2017 01:36:40 -0000, FromTheRafters
wrote:

Some cut due to aioe quotation limits.

All materials conduct, some better than others.

And in this case it's so insignificant it's nothing. Lightning might go
through it....

The U.S. National Electrical Code has a special section, Article
547, for
livestock confinement buildings. Critters are four foot drive compared
to human two
foot drive. That makes them a lot more susceptible to stray current.
It talks about creating an equipotential plane on the concrete floor.
It takes a lot
or rebar and/or wire mesh. I've read it's similar to that for swimming
pools.
Critters won't drink or dairy cows won't release their milk if getting
shocked.

On Sat, 07 Jan 2017 20:53:10 -0000, Dean Hoffman wrote:

On 1/7/17 9:26 AM, James Wilkinson Sword wrote:
On Fri, 06 Jan 2017 01:36:40 -0000, FromTheRafters
wrote:

Some cut due to aioe quotation limits.

All materials conduct, some better than others.

And in this case it's so insignificant it's nothing. Lightning might go
through it....

The U.S. National Electrical Code has a special section, Article
547, for
livestock confinement buildings. Critters are four foot drive compared
to human two
foot drive. That makes them a lot more susceptible to stray current.
It talks about creating an equipotential plane on the concrete floor.
It takes a lot
or rebar and/or wire mesh. I've read it's similar to that for swimming
pools.
Critters won't drink or dairy cows won't release their milk if getting
shocked.

Cows **** and **** everywhere, the concrete is wet. The water conducts, not the concrete.

--
Definition of Necrophilia: That Uncontrollable Urge To Crack Open A Cold One.