can earthing be made in basement ? 3

[electroff]

Hi engineers i need some help
we have this building being constructed and i have been asked if we can install the earthing rods under the basement and not outside the building. Can it be done ? Or is it against the code ?

 

[ScottyUK]

Difficult to answer code-related questions without knowing which code you're governed by.

 

[advidana]

Contact your local building department plans check with this question.

 

[jraef]

Most likely your code will say no. Without proper moisture in the soul, continuity to earth becomes unstable. Often times in a basement, extra measures are taken to specifically EXCLUDE soil moisture for a variety of civil engineering reasons. That might interfere with the proper functioning of an earthing electrode.

But again, this is not the place to ask.


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

 

[waross]

In our jurisdiction we are allowed to install a "Ufer Ground" in the foundation, if there is NO VAPOUR BARRIER BETWEEN THE FOUNDATION AND THE UNDERLYING SOIL. (Ufer Ground: 20 feet of bare copper cable installed in the bottom 2 inches of the concrete foundation.)
Check with your local AHJ (Authority Having Jurisdiction.)

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[ScottyUK]

Any idea where the name 'Ufer' comes from, Bill? I'm familiar with the principles but I've only come across the name through these fora.

 

[waross]

I've wondered that for years myself, John.
But Wiki says:

History

During World War II, the U.S. Army required a grounding system for bomb storage vaults near Tucson and Flagstaff, Arizona. Conventional grounding systems did not work well in this location since the desert terrain had no water table and very little rainfall. The extremely dry soil conditions would have required hundreds of feet of copper rods to be inserted into the ground in order to create a low enough impedance ground to protect the buildings from lightning strikes.

In 1942, Herbert G. Ufer was a consultant working for the U.S. Army. Ufer was given the task of finding a lower cost and more practical alternative to traditional copper rod grounds for these dry locations. Ufer discovered that concrete had better conductivity than most types of soil. Ufer then developed a grounding scheme based on encasing the grounding conductors in concrete. This method proved to be very effective, and was implemented throughout the Arizona test site.

After the war, Ufer continued to test his grounding method, and his results were published in a paper presented at the IEEE Western Appliance Technical Conference in 1963.[1] The use of concrete enclosed grounding conductors was added to the U.S. National Electrical Code (NEC) in 1968. It was not required to be used if a water pipe or other grounding electrode was present. In 1978, the NEC required rebar to be used as a grounding electrode if present. The NEC refers to this type of ground as a "Concrete Encased Electrode" (CEE) instead of using the name Ufer ground.

Over the years, the term "Ufer Ground" has become synonymous with the use of any type of concrete enclosed grounding conductor, whether it conforms to Ufer's original grounding scheme or not.[2]

Yours

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[electroff]

Thanx everyone very helpful !!

 

[ScottyUK]

Thanks Bill, interesting history. I'm familiar with concrete-encased electrodes but had never really considered that someone must have invented them.

 

[cranky108]

Even if it were allowed, I would not do it.

At one time it was the duty of the meter reader to look at the customer instalation to see if they could see any problems, such as a loose ground connection onto the ground rod.
By placing the grounding connection in a basement, it makes it difficult to inspect, and the likely hood is it won't be inspected.

 

[OperaHouse]

In sandy Florida I was working on a jet engine test cell. That engine stand required a lot of concrete and rebar. The test stand was quite a bit better ground than the power grid ground. That caused a lot of problems with signal grounds due to ground currents.

I love these moments of nostalgia, meter readers.