Storm scare....I need some thoughts/opinions

[Mace Canute]

If I ever pour another slab I'll bond it. The thing is here we have periods of drought so severe that the concrete actually separates from contact with the earth. The poster said the concrete contractor left a rebar exposed and he tied into that. So his connection is not concrete encased. I'm old school and 250-A (3) is an addendum. I would love to get Megger readings on those grounds in say- 10-15 years- if I live that long. Hey, BTW, did you ever get a new TV?

Somehow I can't see a slab or grade beam separating from the earth...that would require gravity to cease.

The connection doesn't have to be concrete encased as per NEC 250.68(C)(3)

From What Is A 'Ufer' Ground? | EC Mag

Herbert G. Ufer was a vice president and engineer at Underwriters Laboratories who assisted the U.S. military with ground-resistance problems at installations in Arizona. Ufer's findings in the 1940s proved the effectiveness of concrete-encased grounding electrodes. The military required low-resistance (5 ohms or less) ground connections for lightning protection systems installed at its ammunition and pyrotechnic storage sites at the Navajo Ordnance Depot in Flagstaff and Davis-Monthan Air Force Base in Tucson. Ufer developed the initial design for a concrete-encased grounding electrode that consisted of 1/2 inch, 20-foot-long reinforcing bars placed within and near the bottom of 2-foot-deep concrete footings for the ammunition storage buildings. Test readings over a 20-year period revealed steady resistance values of 2 to 5 ohms, which satisfied the specifications of the U.S. government at that time.

Regarding my TV...http://www.tractorbynet.com/forums/related-topics/338983-my-tv-has-died-post4166479.html#post4166479

 

[Fawken]

I am a retired electric lineman(37 years) so yes I understand the bonding issue.

I believe you. However, as a retired phone company worker I should tell you that tampering with the phone co. ground could cause someone some grief- such as service disconnection for ILU.

 

[Fawken]

Somehow I can't see a slab or grade beam separating from the earth...that would require gravity to cease.

The connection doesn't have to be concrete encased as per NEC 250.68(C)(3)

From What Is A 'Ufer' Ground? | EC Mag



Regarding my TV...http://www.tractorbynet.com/forums/related-topics/338983-my-tv-has-died-post4166479.html#post4166479

Come to Texas. If the intent is to have 20' of surface area contacting the earth and due to drought there is 6' of perimeter around the slab not even contacting the ground on a 40'x20' slab whatever ground you had is compromised.

 

[Mace Canute]

Come to Texas. If the intent is to have 20' of surface area contacting the earth and due to drought there is 6' of perimeter around the slab not even contacting the ground on a 40'x20' slab whatever ground you had is compromised.

Is that statement based on you having meggered a Ufer ground under those conditions or is it just something you think is true?

 

[Fawken]

It is my learned opinion. I do not know the size of the structure that the test you cited was conducted upon. Wouldn't you agree that the bigger the slab the more moisture it can retain toward the center of said slab? For my own personal installations (which I still do selectively) I'll stick to an 8', 5/8" copper clad ground rod and/or cold water copper pipe. Gotta go weedeat. And congratulations on your new TV.

 

[Mace Canute]

It is my learned opinion. I do not know the size of the structure that the test you cited was conducted upon. Wouldn't you agree that the bigger the slab the more moisture it can retain toward the center of said slab? For my own personal installations (which I still do selectively) I'll stick to an 8', 5/8" copper clad ground rod and/or cold water copper pipe. Gotta go weedeat. And congratulations on your new TV.

I agree there is very likely to be more moisture towards the center of a slab which would make a Ufer ground all that much more effective. Concrete absorbs moisture quickly and looses moisture very slowly. The mineral properties of concrete (lime and others) and their inherent pH means concrete has a supply of ions to conduct current.

 

[General Lee]

All this NEC talk did nothing but confuse me lol. I still don't have a solution

 

[Fawken]

All this NEC talk did nothing but confuse me lol. I still don't have a solution

LOL! The solution is ground, and bond and then pray. Lightning is unpredictable and awesomely destructive. The best data centers go to extreme lengths to protect their machines and every now and then they still get zapped. In downtown areas with high-rise buildings there is what is known as a cone of protection. I'm guessing that doesn't help most of the members here.

 

[MikePA]

In downtown areas with high-rise buildings there is what is known as a cone of protection.

A distant cousin of...

 

[General Lee]

LOL! The solution is ground, and bond and then pray. Lightning is unpredictable and awesomely destructive. The best data centers go to extreme lengths to protect their machines and every now and then they still get zapped. In downtown areas with high-rise buildings there is what is known as a cone of protection. I'm guessing that doesn't help most of the members here.

I'm not worried about appliances......I'm want to protect the home.