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#21
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![]() We used 5/8" copper clad steel, or sometimes 3/4" copper clad steel rods. We also used rotary impact hammers to drive the rods down.... often right through a rock or whatever. Hammer-only mode? Or "rotate & hammer" mode? ---Joel Hope I did not confuse ! I used a rotary impact hammer in all my years of ground rod driving, but only used impact mode..... the rotary mode would only turn the hammer head, not the rod . .. anyway. Most of the time I had a sized Bosch tool, not some cheap import. --- Ed K7AAT |
#22
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Sal M. Onella wrote:
Dave Lemper wrote in message ... The soil in central Texas is called Caliche with a lot of clay, CaCO3 & shale. Attempting to drive in a ground rod yielded only a mushroom on top & blisters on me. Local tool rental place has concrete bits, but maximum length of 18 inches. Possibly longer bits are available in a larger city. Renting a back hoe is out. Any suggestions appreciated. Dave WB3DWE Here's a snippet from the state of Washington's website that quotes the NEC: NEC 250-52 (c)(3) (1999 edition) requires that ground rods "be driven to a depth of not less than 8 feet (2.44m) except that, where rock bottom is encountered, the electrode shall be driven at an oblique angle not to exceed 45 degrees from the vertical or shall be buried in a trench that is at least 2½ ft. (762mm) deep." The requirement is that the rod be driven to a depth of 8 feet. If the rod cannot be driven then there is a choice of either driving it at a 45-degree angle or laying it in a trench that is not less than 2½ feet deep. http://www.lni.wa.gov/tradeslicensin...ts/elc0210.pdf. I browsed some newer discussions and found nothing newer to be at variance with the quoted material. The current NEC is $75 if snippets won't do ya'. http://www.nfpa.org/itemDetail.asp?c...RL=Pub licati ons/ You need 25 ohms maximum rersistance (three-point method) to say you have a good ground. or, do what most jurisdictions now require, and build yourself a concrete encased grounding electrode (Ufer ground)... no minimum depth, per se. |
#23
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"Dave Lemper" wrote in message
... The soil in central Texas is called Caliche with a lot of clay, CaCO3 & shale. Attempting to drive in a ground rod yielded only a mushroom on top & blisters on me. Local tool rental place has concrete bits, but maximum length of 18 inches. Possibly longer bits are available in a larger city. Renting a back hoe is out. Any suggestions appreciated. Dave WB3DWE I use a pneumatic rivet gun. Works great. 73, H. NQ5H |
#24
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Jim Lux wrote:
Sal M. Onella wrote: Dave Lemper wrote in message ... The soil in central Texas is called Caliche with a lot of clay, CaCO3 & shale. Attempting to drive in a ground rod yielded only a mushroom on top & blisters on me. Local tool rental place has concrete bits, but maximum length of 18 inches. Possibly longer bits are available in a larger city. Renting a back hoe is out. Any suggestions appreciated. Dave WB3DWE Here's a snippet from the state of Washington's website that quotes the NEC: NEC 250-52 (c)(3) (1999 edition) requires that ground rods "be driven to a depth of not less than 8 feet (2.44m) except that, where rock bottom is encountered, the electrode shall be driven at an oblique angle not to exceed 45 degrees from the vertical or shall be buried in a trench that is at least 2½ ft. (762mm) deep." The requirement is that the rod be driven to a depth of 8 feet. If the rod cannot be driven then there is a choice of either driving it at a 45-degree angle or laying it in a trench that is not less than 2½ feet deep. http://www.lni.wa.gov/tradeslicensin...ts/elc0210.pdf. I browsed some newer discussions and found nothing newer to be at variance with the quoted material. The current NEC is $75 if snippets won't do ya'. http://www.nfpa.org/itemDetail.asp?c...RL=Pub licati ons/ You need 25 ohms maximum rersistance (three-point method) to say you have a good ground. or, do what most jurisdictions now require, and build yourself a concrete encased grounding electrode (Ufer ground)... no minimum depth, per se. The minimum depth is provided by the building code. Since the footer must be below the frost line the resultant Ufer Ground is also below the frost line. If it's not it will be ineffective. -- Tom Horne "This alternating current stuff is just a fad. It is much too dangerous for general use." Thomas Alva Edison |
#25
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Earlier, someone wrote:
Renting a back hoe is out. I just skim-read that as "Renting a black hole is out"... well, why not? -- 73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.co.uk/g3sek |
#26
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![]() The minimum depth is provided by the building code. Since the footer must be below the frost line the resultant Ufer Ground is also below the frost line. If it's not it will be ineffective. To split hairs a bit, you can build a Ufer ground that isn't a structural footer, and so, may not be subject to the frost line rules. |
#27
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Jim Lux wrote:
... To split hairs a bit, you can build a Ufer ground that isn't a structural footer, and so, may not be subject to the frost line rules. In California, in the central valleys, the question is simply, "What frost-line? 8-) Regards, JS |
#28
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In article ,
Ian White GM3SEK wrote: Earlier, someone wrote: Renting a back hoe is out. I just skim-read that as "Renting a black hole is out"... well, why not? Getting your cash deposit back is hell, in those cases. It's as if the rental agency dropped it down... well, you get the idea. -- Dave Platt AE6EO Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
#29
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Jim Lux wrote:
The minimum depth is provided by the building code. Since the footer must be below the frost line the resultant Ufer Ground is also below the frost line. If it's not it will be ineffective. To split hairs a bit, you can build a Ufer ground that isn't a structural footer, and so, may not be subject to the frost line rules. Yes Jim he can. But if he does will frost heaves likely destroy it. When I was younger I spent a lot of time building duct banks and they were always built with the base of the bank below the frost line so that the formation of ice in the soil during a hard winter would not destroy them. Remember that even a ground ring composed of straight wire is buried a minimum of thirty inches deep. The objective in constructing grounding electrodes is to get them down below the permanent moisture level well into the so called water table. I know that the subject area is Texas and the strata he's dealing with is quite hard but he didn't seem to be asking how to install what looks like an electrode but rather what will function as an electrode. -- Tom Horne "This alternating current stuff is just a fad. It is much too dangerous for general use." Thomas Alva Edison |
#30
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Dave, In the upper midwest we use a waterhose and keep the area damp so it
drives easily. Sometimes the rod will go in with very light hammer blows. Hope it works for you.. Lots of luck, Rollie Dave Lemper wrote in message ... The soil in central Texas is called Caliche with a lot of clay, CaCO3 & shale. Attempting to drive in a ground rod yielded only a mushroom on top & blisters on me. Local tool rental place has concrete bits, but maximum length of 18 inches. Possibly longer bits are available in a larger city. Renting a back hoe is out. Any suggestions appreciated. Dave WB3DWE |
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