UFER grounding
- Thread starter SAL568
- Start date
- Location
- New Jersey
- Occupation
- Journeyman Electrician
If there is 20' or more of the 15mm rebar then it qualifies as a CEE and must be used as part of the GES. Why would you want to test it?
*Also please update your location in your profile.
*Also please update your location in your profile.
It's more than 15' but can't say for sure if it's 20'. I'm a beginner in electrical code systems so if you could simplify CEE or GES. By the way, I'm an engineer by profession that's why I want to know things by measuring/testing them.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
If the rebar is less than 15' in total length then you cannot used it as a grounding electrode. GES= grounding electrode system. UFER is a slang term for CEE, concrete encased electrode. CEE is the proper term and the one you should be using.
Joe.B
Senior Member
- Location
- Myrtletown Ca
- Occupation
- Building Inspector
250.52(A)(3)
Concrete-Encased Electrode. A concrete-encased electrode shall consist of at least 6.0 m (20 ft) of either (1) or (2):
1. One or more bare or zinc galvanized or other electrically conductive coated steel reinforcing bars or rods of not less than 13 mm (½ in.) in diameter, installed in one continuous 6.0 m (20 ft) length, or if in multiple pieces connected together by the usual steel tie wires, exothermic welding, welding, or other effective means to create a 6.0 m (20 ft) or greater length; or
2. Bare copper conductor not smaller than 4 AWG
Metallic components shall be encased by at least 50mm (2 in.) of concrete and shall be located horizontally within that portion of a concrete foundation or footing that is in direct contact with the earth or within vertical foundations or structural components or members that are in direct contact with the earth. If multiple concrete-encased electrodes are present at a building or structure, it shall be permissible to bond only one into the grounding electrode system.
Informational Note: Concrete installed with insulation, vapor barriers, films or similar items separating the concrete from the earth is not considered to be in "direct con-tact" with the earth.
Concrete-Encased Electrode. A concrete-encased electrode shall consist of at least 6.0 m (20 ft) of either (1) or (2):
1. One or more bare or zinc galvanized or other electrically conductive coated steel reinforcing bars or rods of not less than 13 mm (½ in.) in diameter, installed in one continuous 6.0 m (20 ft) length, or if in multiple pieces connected together by the usual steel tie wires, exothermic welding, welding, or other effective means to create a 6.0 m (20 ft) or greater length; or
2. Bare copper conductor not smaller than 4 AWG
Metallic components shall be encased by at least 50mm (2 in.) of concrete and shall be located horizontally within that portion of a concrete foundation or footing that is in direct contact with the earth or within vertical foundations or structural components or members that are in direct contact with the earth. If multiple concrete-encased electrodes are present at a building or structure, it shall be permissible to bond only one into the grounding electrode system.
Informational Note: Concrete installed with insulation, vapor barriers, films or similar items separating the concrete from the earth is not considered to be in "direct con-tact" with the earth.
Thanks Joe, I would also like to know how to test if this ground rod has required resistance.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
It is not a ground rod electrode or is it? Your thread title says UFER or CEE. Which is it?
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Surprisingly, these types of electrodes do not have a specified resistance value.
You might want to look into its history, search for Herbert G. Ufer.
- Location
- Illinois
- Occupation
- retired electrician
As others have said the NEC does not specify a minimum resistance for a concrete encased electrode.
However you could test it using a fall of potential grounding electrode resistance tester, or maybe with a clamp on ground resistance tester.
Joe.B
Senior Member
- Location
- Myrtletown Ca
- Occupation
- Building Inspector
*Please confirm with a qualified professional*
*Do not perform experiments without extensive training and supervision*
That being said, check out this old thread:
Checking 25 ohms ground rod
What is the easiest and cheapest means of checking the resistance in a ground rod driven into the ground?
forums.mikeholt.com
readydave8
re member
- Location
- Clarkesville, Georgia
- Occupation
- electrician
I don't think a multimeter will give usable results
It's CCE. Can't we use it as a ground electrode?
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
If it meets all the CEE requirements found in the code it can be used as the grounding electrode.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Wouldn't it be " . . . must be used . . . "?
Can you simplify if it is a good ground or not?
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
I would make the more complete change "...must be used as a grounding electrode....."
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
The NEC does not care whether or not it is proved by measurement to be a good ground electrode. The high point of Mr. Ufer's discovery was that even in rocky and/or dry soil of low conductivity, the area of a compliant CEE is so large that the CEE will generally be the best ground electrode available and will be satisfactory for the intended purpose of a GES, and more. It is generally good enough for instrumentation and radio transmitter grounding as well.
Also, if the CEE spans a large area (large horizontal extent), then using the Fall Of Potential method of calculating electrode to earth impedance requires a particularly long base line with no installations or other ground electrodes along the way.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
Yes. However it has to meet the requirements found in the code. It seems unlikely that rebar in the floor slab would be connected electrically to the twenty feet of rebar the code talks about found in the foundation.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
If it qualifies as a CEE then you are required to use it. We're all guessing as to what you're actually describing. You've mentioned 15mm rebar which is larger than 1/2" so the rebar is large enough. What's lacking in your description is where is this rebar located (is it in the footing) and how long is it when all of the rebar is tied together (20' or more).
The rebar is in building's columns. Total depth of column under ground ecased with concrete is over 15' confirmed.then the columns are raised to first floor (12' hieght) where rebar is protruding from column.
If this infromation suffices.