QUESTION for ya Doc

Posted by John T on April 28, 2012 at 09:53:16 from (216.249.82.117):

In Reply to: Re: Electrical question posted by dr sportster on April 28, 2012 at 08:32:38:

Mornin there Doc, no offense and NOT wanting to argue, just learn (HELP ME AND THE OTHERS OUT HERE IF YOU CAN), You and Buick are gonna have to explain that process to me of your running a hot wire out to the "Grounding Electrode" driven in earth copper rod (which gets bonded to the service Neutral/Ground via a No 4 bare copper "Grounding Electrode Conductor) and connecting the hot wire to that copper rod to measure resistance???????? Resistance of what??? The resistance in that 120 VAC circuit you just made between Hot and Neutral via its bond to the No 4 bare copper "Grounding Electrode" conductor to the "Grounding Electrode" copper rod is veryyyyyyyyyyy veryyyyyyyyyy low ohms (No 4 wire is low resistance between that rod and Neutral) and will pop that breaker almost instantly

Its been years since I was a design engineer and our installation used an expensive Megger to test the integrity of the Grounding Electrode (driven into earth copper rod) and if it didnt pass we were required to drive yet another copper ground rod.....We didnt run a hot wire out to the copper rod to measure current or anything???

Heres how the service entrance wiring including the Neutral and Equipment Ground Buss and the No 4 bare copper "Grounding Electrode Conductor" and the copper rod "Grounding Electrode" are all configured

1) At the incoming main service panel the Neutral Buss is bonded to the Equipment Ground Buss.

2) The Neutral/Ground is connected to a "Grounding Electrode Conductor" (No 4 bare copper wire) which leads outside where its bonded to a "Grounding Electrode"

3) A "Grounding Electrode" is usually a "Made Electrode" such as a copper rod or rods driven into the earth or perhaps other suitable "grounding electrodes" such as buried metal water pipes or structural foundation steel etc.

4) SOOOOOOO if you attach a hot wire out to that copper rod, theres 120 VAC across an almost dead short as 10 to 20 feet No 4 bare copper wire AINT MUCH RESISTANCE and the breaker will pop almost instantly

5) AND THATS TRUE REGARDLESS IF THE ROD IS DRIVEN IN THE EARTH OR JUST LAYING THERE OR UP A MONKEYS BEHIND LOL

Nowwwwwwwwwww if you didnt bond the Grounding Electrode copper rod to the service entrance Neutral (as is required at weatherhead riser or meter base or in panel) and you ran a hot wire outside and stuck it in the earth BUT NOTTTTTTTTT TO THE COPPER ROD then there would be measureable mother earth resistance between where you stuck the hot wire and over to the copper rod grounding electrode BUT IF YOU TOUCH THE HOT WIRE DIRECT TO THE ROD the resistance is lowwwwwwwwwww and the breaker will pop instantly as No 4 bare copper wire just aint much resistance between where it attaches to the rod and to the incoming service Neutral (panel or meter base or weatherhead riser)

Sooooo please explain how wiring off a 20 amp breaker and connecting it outside direct to the ground rod (assuming all is wired proper and per code) is a measure of the resistacne of what???

Of course if you run a hot wire out to earth NOT on the rod some current will flow and the resistance is that of the earth between your wire and over to the driven rod and that depends on distance,,,,,,,,,,moisture and mineral conrent of the earth,,,,,,,,,,how much the rod has contact with earth etc etc etc...BUT I JUST DONT UNDERSTAND HOW THATS ANY GROUND INTEGRITY TEST LIKE A MEGGER PERFORMS???????

PS In the event the rod is nottttttt connected to the Neutral (as NEC and alllll codes Ive ever seen require DUH) and you run a hot wire to the rod,,,,,,,then current will want to flow allllllll the way out to where the service transformers Neutral is bonded to Mother Earth and that may be 50 or more feet of earth and thats a bunch of resistance and low current flow but I dont see how that measures much of anything meaningful since it depends on how FAR FROM THE TRANSFORMER youre located.....ya gotta explain your and Buick mans method

Never too old to learn, please help us all out here LOVE SPARKY CHAT AND LEARNING (even at my advanced age lol) PLUS HELPING OTHERS

Ol John T

Replies:

• Re: QUESTION for ya Doc Stephen Newell 06:20:53 04/29/12 (1)
  • Re: QUESTION for ya Doc dr sportster 07:22:22 04/29/12 (0)

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