John, they do make thread together rods, when I did commercial communications I have used them at comm sites. Here, a 10ft ground rod is fine as are wet gumbo soil makes a pretty good ground. The NEC requires 2 ground rods or a ground rod and a ufer ground, which can be rebar in the slab, metal water line or metal bldg. if in contact with the earth via rebar or poles. I usually install 2 rods. Most 10 ft ground are easy to push in the ground with just your hands. I just a few weeks ago installed additional rods at a hams house in the Heights. I wired a home in Elgin, just outside of Austin. Had to install horizonal ground rods as the ground was solid rock 2 ft down. I always tie to an existing rod but always add an additional rod as you never know if the old ground rod is 10ft or 18” Here in the Houston area, testing is not necessary because of the soil, but as the video shows, it is a neat test. You are correct in your bends in the grounding conductor, they will act as a choke if made sharp, also, you should no run the ground wire in metal conduit for the same reason unless you bond the ground wire to the conduit at both ends. As far a lightning goes, remember, all the wiring the strike travels thru on the way to the earth has resistance & inductance, so by the time it gets in the circuit the voltage & current are greatly reduced, still high, but since the duration is short, a good grounding system will dissipate quickly. Robert
From: BVARC <[email protected]> On Behalf Of john Parmalee via BVARC Sent: Tuesday, May 24, 2022 6:31 PM To: [email protected] Cc: john Parmalee <[email protected]> Subject: Re: [BVARC] grounding >From what the great video says, if you are comfortable working with 120V the >simplest way to check out a ground rod is to see how much current it will draw >and do the math. Don't attempt this without experience working with a live >circuit. I have been told by licensed electricians that when a new service is >turned up if there is the stub of a ground rod sticking out of the ground it >is good. No testing required. The thing I don't know is where to get the ground rod to ground rod connections and the ground rods with the blunt ends so they can match the previously driven rod. Lowes only carries the 8 or it 10-foot rods and the coupling to the flex wire to the service box. I checked Amazon and found nothing. I am told the local rental yard will rent a hammer drill and the ground rod driving adapter. Another comment regarding the ability of a ground to carry a lightning strike. All bends of the ground wire should have the gentlest bends possible. A strike of lightning is a very fast rise time having many harmonics. We know this because we can hear lightning almost to the VHF bands, A bend will look like an inductor and raise the instant ohmic value of a ground rod. On the other hand, a few turns on a coax or power source lead will increase the ohms to you rig.it will not protect against a direct hit but might fend off some induced current from a nearby strike. In south Florida it is common to tie several knots in your modem phone line. In Michigan they wrap a phone line around a ¼” bolt , some washers and a nut.. John Parmalee [email protected] <mailto:[email protected]> 281-380-3811 K5VGM WI2XLJ In a message dated 5/23/2022 7:54:42 PM Central Standard Time, [email protected] <mailto:[email protected]> writes: If any one is interested in ground rod resistance, you can watch the link below. One thing I want watchers to note, they have 2 50ft ground rods connected together, they hook the hot side of a 120v ckt to them and it only pulls 13 amps (not enough to trip a breaker), that is why the grounding system must have a bond back to the power co ground always. Note this is not related to the RF grounds used as a counterpoise to an antenna system other than they will be tied together at a point. Robert https://www.youtube.com/watch?v=Yg6G5VUSsWA ________________________________________________ Brazos Valley Amateur Radio Club BVARC mailing list [email protected] <mailto:[email protected]> http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org Publicly available archives are available here: https://www.mail-archive.com/[email protected]/ <https://www.mail-archive.com/[email protected]/>
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