What does UFER mean ???
- Thread starter foonfats
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Re: What does UFER mean ???
It is just another name for Concrete-Encased Electrodes.
Take a look at 250.52(A)(3)
It is just another name for Concrete-Encased Electrodes.
Take a look at 250.52(A)(3)
big john
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Re: What does UFER mean ???
I originally thought "Ufer" had developed from the initials for "Under Footing" but it is actually named after the guy who invented it: Herbert Ufer.
-John
I originally thought "Ufer" had developed from the initials for "Under Footing" but it is actually named after the guy who invented it: Herbert Ufer.
-John
Re: What does UFER mean ???
During World War II, a retired Vice President of Underwriters Laboratories, Herbert G. Ufer, developed it for the U.S. Army. Bomb storage vaults were being built, and possible static and lightning charges could induce detonation problems. Ground conductivity was poor, and to be effective enough, ground rods would have to be driven several hundred feet. After much research and testing Mr. Ufer advised the Army to make connection to the steel bar that would internally reinforce the concrete foundation. He had determined that concrete was more conductive than all but the best soil, and that this improved semiconducting characteristic would enhance surface area contact with the surrounding soil. The wire ties normally used would be extra secure, and attention would be given to bonding or welding the lattice- type network together. The Army adopted the idea, and built the vaults as
specified.
After construction ground resistance tests were made. No measurement exceeded five ohms. This value was considered extremely low for the local soil conductivity. Later tests confirmed stability. Mr. Ufer went on to develop the concept of concrete encased grounding electrodes. Many of his findings are detailed in IEEE Transactions paper # 63-1505. His system has since been used by the military, utility companies, Lake Tahoe lifts, and industry throughout the country.
During World War II, a retired Vice President of Underwriters Laboratories, Herbert G. Ufer, developed it for the U.S. Army. Bomb storage vaults were being built, and possible static and lightning charges could induce detonation problems. Ground conductivity was poor, and to be effective enough, ground rods would have to be driven several hundred feet. After much research and testing Mr. Ufer advised the Army to make connection to the steel bar that would internally reinforce the concrete foundation. He had determined that concrete was more conductive than all but the best soil, and that this improved semiconducting characteristic would enhance surface area contact with the surrounding soil. The wire ties normally used would be extra secure, and attention would be given to bonding or welding the lattice- type network together. The Army adopted the idea, and built the vaults as
specified.
After construction ground resistance tests were made. No measurement exceeded five ohms. This value was considered extremely low for the local soil conductivity. Later tests confirmed stability. Mr. Ufer went on to develop the concept of concrete encased grounding electrodes. Many of his findings are detailed in IEEE Transactions paper # 63-1505. His system has since been used by the military, utility companies, Lake Tahoe lifts, and industry throughout the country.
Re: What does UFER mean ???
It only takes twenty feet of rebar or bare copper conductor encased in concrete to make a concrete encased electrode.
In order to make a true Ufer ground the footer and floor reinforcing steel will be double tied into one continuous metallic grid before the concrete is poured and the grounding electrode conductor will be run to the piece of rebar that is stubbed up to provide the connection point. These are usually built at magazines, broadcast stations, Radio relay stations, and similar installations were a very low grounding impedance is critical to the safe or uninterrupted operation of the facility. This technique was originally developed by Ufer for magazines in the desert south west to obtain a low enough grounding impedance to safeguard explosive magazines from lightning strikes.
Tom H
Not Quite. All Ufers are concrete encased electrodes but not all concrete encased electrodes are Ufers.
It only takes twenty feet of rebar or bare copper conductor encased in concrete to make a concrete encased electrode.
In order to make a true Ufer ground the footer and floor reinforcing steel will be double tied into one continuous metallic grid before the concrete is poured and the grounding electrode conductor will be run to the piece of rebar that is stubbed up to provide the connection point. These are usually built at magazines, broadcast stations, Radio relay stations, and similar installations were a very low grounding impedance is critical to the safe or uninterrupted operation of the facility. This technique was originally developed by Ufer for magazines in the desert south west to obtain a low enough grounding impedance to safeguard explosive magazines from lightning strikes.
Tom H
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