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Using the 2002 NEC, What's wrong here? Note: As this area is sometimes used as a reference for Vocational studies we request that comments be kept to the subject as much as possible. Thank You for your cooperation in this matter. [This message has been edited by Joe Tedesco (edited 08-09-2002).]
Joe Tedesco, NEC Consultant
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Joined: Mar 2001
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250.53 (G) Last sentence. The upper end of the electrode shall be flush with or below ground level unless the aboveground end and the GEC attachment are are protected against physical damage. BTW, I would have the conductor on the other side of the rod, with the set screw biting into the rod itself.
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Joined: Apr 2002
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I believe that the "acorn" clamp is used incorrectly. As Redsy said, the method we have always used is the rod is between the setscrew and the conductor. In the manner it's installed, physical damage will be inflicted on the conductor.
Also. the rod must be flush or below grade, or protected from physical damage.
HotLine1 John
John
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Joined: Aug 2001
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We use similar style clamps in England.
I agree with you -- I always put the cable on the opposite side to the set screw.
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Joined: Apr 2002
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Appears to me that the rod is cut about half-way-thru just below the acorn clamp losing circumference.
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Joined: Apr 2002
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That 'groove' is there so an inspector can tell if the entire rod is driven into the ground. Pulling these things out after hitting ledge or a stone is not a fun or productive thing to do. (Why does it happen at 6 1/2 feet?)
Wondering what are some techniques some of you guys use for driving them in or pulling them out?
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Joined: Apr 2002
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We us a Bosch Demo Hammer with a ground rod attachment. Works great and easy on the body.
Curt Swartz
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Joined: Jan 2002
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I use a rotary hammer with rod attachment. Best money I ever spent. When I have to do it by hand I use a "monster maul". It's an over sized wood splitting maul that has a 32" hollow pipe handle and a 16 pound head. Just slide handle over rod and go.
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Joined: Mar 2002
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We put in 18 one day at a mobile home park we set up. Put 17 of them in with the front endloader bucket on a 40hp Kabota tractor. Start them in a hole with a shovel and let the bucket down. One hit a rock and doubled back and came back out about two and half feet above grade. We replaced it with a new one drove with a Milwaukee demo hammer and ground rod attachment.
Lighting the way
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I have found radically different soil conditions within ten miles...from mean hardpan to one that just about was lost in “quicksand”-like conditions. I’ll side with sparky the ¾-inch GRC is just right for ¾-inch rods. A ±3x18-inch shaft scrap can be welded to a ¾x6-inch GRC nipple, and three more nipples strung together with couplings. After reaching ~2-foot rod exposure, depending on elbow room, remove the nipples one at a time, or, reversing the driver and use the GRC attachment as a handle to limit stoop labor.
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Joined: Oct 2001
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Who pulls them out? It's cheaper to leave them in and drive another. To drive them down, ever use water? Plunge the rod up and down, like clearing the tiolet, adding water all the time. It's a poor man's roto-hammer.
kduke
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Joined: Apr 2001
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We do ground rods somewhat differently here. First of all, we have to use a 10' rod. Since our ground has a lot of rock and hardpan, this means that about half the time it is necessary to bang in two rods (at least 6' apart) the 7-8' that they'll go. Secondly, it's dry out here. The inspectors like to see the rods somewhat away from the wall, at the roof's drip line. Every bit of moiosture helps conductivity. We are required to use #4 (1/4") solid wire (or larger). The wire must be within EMT all the way to the ground rod. Finally, the inspector likes to have the rod project out of the ground a few inches, so he can inspect the proof mark that identifies the rod (so a short rod isn't just cut off, then the saw marks banged up some). I use a demolition hammer- slightly larger than a "roto hammer", but smaller than a "jack hammer." I also use a "post pounder-" a length of pipe with handles, and a good, heavy slug of steel at the end. (Good welding class project!) Finally, a problem I've encountered with service changes is that old buildings frequently have footings about 5' down that project out some distance from the wall. Lots of luck with the ground rod if you hit them!
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