McDowellb
Banned
- Location
- Beverly Hills, CA
I am trying to find out what other jurisdictions are requiring for the minimum depth of an out of footing concrete encased electrode. There is nothing in the 2002 that requires a certain depth.
Depth of Grounding Electrode
- Thread starter McDowellb
- Start date
- Status
I am trying to find out what other jurisdictions are requiring for the minimum depth of an out of footing concrete encased electrode. There is nothing in the 2002 that requires a certain depth.
bphgravity
Senior Member
- Location
- Florida
Are you asking in regard to protection from damage or for the sake of functionality?
McDowellb
Banned
- Location
- Beverly Hills, CA
I suppose both would be a concern. I read an article on the original test that Mr. Ufer did and I saw nothing in his tests that had depths.
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Most applications the connection comes out of the top.
If you want to protect it use a length of 3/4" PVC sch 80.
A common method is a 1/2" L shape of rebar stubbed up thru the footing top, with an acorn clamp on it.
If you want to protect it use a length of 3/4" PVC sch 80.
A common method is a 1/2" L shape of rebar stubbed up thru the footing top, with an acorn clamp on it.
bphgravity
Senior Member
- Location
- Florida
tom baker said:
Just remember there are technically only 2 acorn style clamps listed for use on rebar.
Erico (Eritech): Model # CP58 - #4 rebar
ILSCO: Models # GRC-38, GRC-48, GRC-68 - #3, 4, and 5 rebar
The code does not require a minimum depth for out of footing concrete encased electrode due to the fact that many other types may be used. (2005)NEC 250.52 states the different types of electrodes and hoe they shall be installed. Concrete encased electrodes are only required to be installed in the bottom of the foundation of the building. The minimum building foundation is 12" but may be deeper based on the size of the building. Why don't you just install a ground rod?
- Location
- Logan, Utah
If your area is on the 2005 NEC and you have re-bar in the footings you must use the re-bar as a grounding electrode.
The new wording in 250.50 "where present" instead of the old wording "where available" now clarifies the intent, that we must use the re-bar in the footing as a grounding electrode.
JMHO, Chris
depth of electrode
depth of electrode
I belive his question is about the depth of an out of footing concrete encased electrode. There is no building steel when you have an out of footing UFER ground. If I were to install an out of footing concrete encased electrode (UFER) in a service pedastal would there be a minimum depth required for this UFER ground. The code has requirements only for plates, rods, and pipes. Also many buildings here in sacramento have P-T(post tension) slabs and no footings, only a tickened edge so where should the UFER be located then. With a P-T slab as a foundation it placed on top the soil.
depth of electrode
I belive his question is about the depth of an out of footing concrete encased electrode. There is no building steel when you have an out of footing UFER ground. If I were to install an out of footing concrete encased electrode (UFER) in a service pedastal would there be a minimum depth required for this UFER ground. The code has requirements only for plates, rods, and pipes. Also many buildings here in sacramento have P-T(post tension) slabs and no footings, only a tickened edge so where should the UFER be located then. With a P-T slab as a foundation it placed on top the soil.
Last edited:
- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
Marc B, welcome to the forum. 
I think, at the end of the day, if you physically can't create a concrete encased electrode, and there isn't one already present, then the answer is clear: we'd need to use something else.
A requirement to use one at all costs when present is not a requirement to install one at any cost if it's not already present.
I think it's due to the possibility that they consider "near the bottom of a foundation" is easy enough to enforce without further defining it, IMO. However, we have argued this in the past. I would provide you with a link to the discussion, but apparently I've never uttered "footer" and "foundation" in the same post, and scarcely ever said "Ufer" - according to the search engine.marcb said:
Can you clarify this statement?marcb said:
It's been a while since I looked, but I'm fairly sure all the P-T slabs in our area generally have footers.marcb said:
I think, at the end of the day, if you physically can't create a concrete encased electrode, and there isn't one already present, then the answer is clear: we'd need to use something else.
A requirement to use one at all costs when present is not a requirement to install one at any cost if it's not already present.
ryan_618
Senior Member
- Location
- Salt Lake City, Utah
The footing depth is a building code issue. It must be below the frost level, and below the virgin soil.
sandsnow
Senior Member
- Location
- Southern California
We've been using 12 inches as a standard. Anything different might be approved after consideration.
Once we had a thickened slab, 24 to 36 inches thick. We considered the entire thing a giant footing as far as the NEC went.
We have some condo's sitting on a 12 foot thick raft slab. Again the entire thing was a footing. Just put the copper in the bottom.
People always want to put it in the pour strip of a tilt up bldg. Usually be cause it got missed during footings. We do not allow it typically. If the strip is deep enough, we have. By deep enough we mean 12 inches.
We used to always require it in the exterior footing. Interior grade beams were not acceptable. The reson being is that is how Mr. Ufer tested it (so I was told). The NEC does not specify, so interior grade beams are ok now.
Once we had a thickened slab, 24 to 36 inches thick. We considered the entire thing a giant footing as far as the NEC went.
We have some condo's sitting on a 12 foot thick raft slab. Again the entire thing was a footing. Just put the copper in the bottom.
People always want to put it in the pour strip of a tilt up bldg. Usually be cause it got missed during footings. We do not allow it typically. If the strip is deep enough, we have. By deep enough we mean 12 inches.
We used to always require it in the exterior footing. Interior grade beams were not acceptable. The reson being is that is how Mr. Ufer tested it (so I was told). The NEC does not specify, so interior grade beams are ok now.
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: Acorn Clamps
Bryon, so the listing for acorn clamps is specific and states rebar?
Bryon, so the listing for acorn clamps is specific and states rebar?
bphgravity
Senior Member
- Location
- Florida
Yes. Per UL category KDER,
Here is a complete list:
There are currently only (2) “acorn” style clamps listed for use with REBAR:
Erico (Eritech): Model # CP58 - #4 rebar
ILSCO: Models # GRC-38, GRC-48, GRC-68 - #3, 4, and 5 rebar
Other UL listed Clamps for use with REBAR:
Erico (Eritech): Model # EK 16 / EK 17
ILSCO : Model # BGC-2T-DB, BGC-2P-DB, BGC-2PS-DB, BGC-4/0P-DB, BGC-4/0S-DB
Galvan: Model # JRD
Bridgeport: Model # RB-16, RB-17
Regal Fittings: Model # 8181
Consolidated Manufacturing International: Model # JRD
Greaves Corp: Model # J29-DB, J30-DB, J31-DB
NSI Polaris: Model # G140DB / GLC140DB
Sigma Electric: Model # C-11N, C-11BN, C-11, C-11D, C-11DN, RBC-1D
Halex Company: Model # C-11
Thermocraft: Model # JRD, JRD+
Thomas and Betts: Model # CC1C-45R, CC2C- 45R, CC10C-56R, CC20C-56R, CC40C-56R
Here is a complete list:
There are currently only (2) “acorn” style clamps listed for use with REBAR:
Erico (Eritech): Model # CP58 - #4 rebar
ILSCO: Models # GRC-38, GRC-48, GRC-68 - #3, 4, and 5 rebar
Other UL listed Clamps for use with REBAR:
Erico (Eritech): Model # EK 16 / EK 17
ILSCO : Model # BGC-2T-DB, BGC-2P-DB, BGC-2PS-DB, BGC-4/0P-DB, BGC-4/0S-DB
Galvan: Model # JRD
Bridgeport: Model # RB-16, RB-17
Regal Fittings: Model # 8181
Consolidated Manufacturing International: Model # JRD
Greaves Corp: Model # J29-DB, J30-DB, J31-DB
NSI Polaris: Model # G140DB / GLC140DB
Sigma Electric: Model # C-11N, C-11BN, C-11, C-11D, C-11DN, RBC-1D
Halex Company: Model # C-11
Thermocraft: Model # JRD, JRD+
Thomas and Betts: Model # CC1C-45R, CC2C- 45R, CC10C-56R, CC20C-56R, CC40C-56R
- Status