Friday, July 16, 2021

It's Friday, the Start of a "Grounding and Bonding" Weekend!

 Sorry, but not FFF like Irish hands out.

Going to try and plant the first of my three ground rods tomorrow, and I'll be using my "Deep Root Watering" yard tool so I can at least get the first 30" of rod slid in before I use my ground rod driving attachment in a demolition hammer to drive it in the rest of the way.

Watering device:

This isn't the exact one I have, but it's very similar. It's a steel tube with a hard point on the end, and three holes to let the water out. You turn the water on a bit, and then push it down into the dirt, which usually dissolves and moves out the way, allowing you to insert the rod down to about 30". Unless you hit a rock, in which case you lift it up, move it a few inches, and start over. I'll leave the water on a trickle for a few hours like when I water the trees, and hopefully enough will collect in the soil so the remaining 6' of ground rod can be driven in.

And this yard has LOTS of rocks in places! It usually takes me three or four tries over by the ash tree before I can get the rod inserted beyond 6".

Once you have the hole made, you insert the ground rod, tap it down until it hits the bottom of your new hole, and drive it in the rest of the way using an adaptor:

In a demolition hammer:

I've done this before, and using the power tools is far better than battering the end of the ground rod with a sledge! It's also reeeal hard to smack a ground rod that's still 6' out of the ground and waving around in the breeze while you're trying to stand on a ladder. With another set of (gloved) hands to help keep the rod vertical, you just hold and guide the demo hammer, and let it do the work.

At the top of the ground rod will be a set of solid copper plates that clamp the rod, and allow me to mount the surge suppressors, as seen below, fully assembled.

This will be mounted at the house, just below my "Coaxial Entrance Box", where the cables enter the house.

At the base of each of the two 4x4's I'm planting as antenna supports will be another ground rod/surge suppressor, and those two rods will be bonded together with some #2 solid-copper wire. I'd go the full "Perimeter Ground" route, but the cost of the copper would be excessive, and there might be a code issue with bonding it to the main house ground, aka "Utility ground", which is usually how it's done.


More pix to come as work progresses.





16 comments:

  1. Living in an area with Florida sizes lightning, I think you are wise.

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    1. Especially with a new radio....

      The only protection I have now is pulling the cables when the weather threatens, and immediately if I hear thunder/see a flash.

      It's very difficult and expensive to have total protection from a direct hit, but this approach affords me some protection for nearby hits, like SiliconGreybeard got clobbered with last year. It's about equal parts Science, Art, and Gut Feeling/Wizardy in putting together a grounding system, and this one has a lot of the things I learned over the years. The soil conductivity here is rather poor, so extra ground rods bonded together are called for.

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  2. Venturing into something I know little about, are any rebars exposed on top of your foundation? Common practice in this area is to tie all together around the perimeter for extra strength.

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    1. We have some stubs visible in the garage, but nothing easy to reach. I'm leery of using rebar, as if you do get a huge hit, it can blow the concrete apart if the rebar wasn't installed with grounding in mind. It has to be tied together properly, and have some ground rods driven in and bonded to it before the concrete is poured.

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  3. Anything that means not beating up my shoulders is a great idea.

    I stumbled across an attachment for the pressure washer that allows me use it as a drain pipe cleaner. (sewer jetter)
    I wonder if the high pressure water jet gizmo would aid in your ground rod job?

    What could possible go wrong with hooking up a hundred feet of hose and a special nozzle to my gasoline powered pressure washer washer and using it to wash out waste piping inside the house? :)

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    1. The last time I drove ground rods by hand was in high-school. I had two big, burly buddies come over, and we took turns slugging the things into the dirt.

      I learned the demo hammer trick from a friend who used it all the time. I can rent one from HD for about $50/4hrs. I might just buy an inexpensive one, as I know I'll be adding more in the future.

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  4. Replies
    1. Yeah, they're a real PITA here. This mile square used to be the CSU Dairy farm, but I bet they scraped all the good dirt off before they built the houses.

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  5. Drjim,

    Down here in the Texas Hill Country, the rocks are numerous. I have driven in ground rods in the last few years; you are right about them waving around. The bedrock is so shallow around my hamshack that I do the manual driving at 45 degrees.

    A local ham who is a retired electrician has a hammer drill/demolition hammer. He will come and drive ground rods in if he has the time. They go right into the limestone with little difficulty. I know the ground here is lousy but you need it.

    What kind of code problem is there with doing the "Perimeter Ground"? I know that the National Electrical Code wants all grounds bonded together. I guess the locals there could be as bad as our electric coop in some ways making up strange requirements out of thin air.

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  6. Yeah, the soil here is a mix of clay, sand, small rocks, and organic matter. It's "brown dirt" unlike the "black dirt" I grew up with. At least it's not the "black adobe" we had in SoCal, that stuff's like black concrete!

    My buddy that taught me the demo hammer trick had a 40' trailer tower, and did a lot of mountain-topping for VHF/UHF contests. He guyed his tower to steel spikes he made, and drove into granite on the mountaintops with his Makita demolition hammer. Depending on where he went, he said he could use the spikes he drove in during previous operation. Some had been in the rock several years, and showed no signs of looseness.

    My concerns about a "code problem" comes from *me* doing the work. If you connect anything to the panel it needs to be done by a licensed electrician, and inspected by the city. I don't know if that applies to the bare #10 or #12 solid copper wire running around the house for the cable TV people to ground their things to. It might be considered NOT part of the panel, and it's OK to make a connection to it. I suppose I could discretely tie into that. It's what I was planning to do with the surge suppressor on the discone antenna I want to plant on the North side of the house. There's a disconnected cable TV run going into the basement workshop there that I can use so I don't have to worry about getting a cable through the foundation.

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    1. I didn't think of the aspect of you doing the work as I am just a Texas Rural Rube. Most Texas Counties have no "zoning" outside of the incorporated towns and cities and therefore you have no oversight. That is both good and bad. I have done a bunch of my own wiring but I do know a lot about how to do it right (I had a master electrician comment positively on my ability). The bad is that some idiots create fire and electrical hazards and shouldn't be allowed to do more than flip switches. Too, they can screw up plugging stuff into walls.

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    2. The zoning codes for Amateur Radio antennas are pretty liberal here. There's no specific city code for the antenna and support structure. The city says if it meets the Larimer County code for Amateur Radio antennas, that's plenty good for them. The County code just says basically if it falls down, it has to land on YOUR property. Oh, and you have to follow any applicable FCC regulations. Easy-Peasy!

      HOA's are another matter entirely, and we backed out of two very nice affordable houses we looked at because of the HOA rules.

      Since this qualifies as a connection to the electrical system, it has to meet those codes, and the NEC, and be done by a "Licensed (taxed) Electrician", and inspected.

      I know I can do this type of work better than most Electricians because they don't do this stuff. They follow The Code, and this is a specialty area within the code. An Industrial Electrician, or the guys who install towers and antennas for commercial use could do it, but there goes the price.

      The connection to the electrical system ground is good for draining off static charges caused by wind and precipitation. I'll probably sneak a connection to it, and cover it up with dirt, as everything I use is rated for direct-burial. The rods at the base of the antenna supports, and at the RF entrance panel, are there to try and mitigate large surges, like SiliconGreybeard got clobbered with last year.

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  7. A Tee post driver could work if you don't hsve a hammer drill.

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    1. Thanks, I hadn't thought of that. I'll check them out.

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    2. Now that my memory has been tickled by KurtP, a t-post driver is what I used the last couple of times until I start hitting the dirt and then I switch to something else, generally a sledge hammer.

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    3. I know some of the in-laws have demo hammers. I'll have to see if I can arrange to borrow one. Otherwise I may buy one of the inexpensive (relatively) $200 models. I'm not bustin' up driveways or streets, just driving ground rods.

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