Audiophile-grade ground rod?

The electrician installed 2 ground rods 6 feet apart when I needed to have a new panel box to replace my old one , it's now code where I live. 

@jea48
2 rods tied to the panel’s ground buss bar and 6’ apart, correct?

@lowrider57 ,

I assume you are referring to the earth grounding for an electrical service.
"The Grounding Electrode System".

6’ apart is the minimum distance required by NEC. The ground rods can be, and is better, if they are at least the length of the rods apart. (8’ rod, 8’ apart). As I remember, Just going from memory, IEEE recommends the ground rods should be twice the length of the rod apart. (8’ rod 16’ apart).

So why don’t electricians install the rods farther apart? Because they only have to follow the NEC and the AHJ (Authority Having Jurisdiction). FWIW, NEC is bare minimum electrical safety standards, requirements.
Time = money. The further the rods are driven apart from one another the more hand digging to bury the #6 solid bare copper ground wire that will connect the rods together. Add to the labor cost is the additional cost of the longer #6 solid copper ground wire. Why do electricians use 5/8" x 8’ ground rods? Because that is the minimum diameter and length required by the NEC.

FWIW, for my electrical service I drove three 5/8" x 10’ ground rods about 15’ apart from one another. I used #4 solid copper ground wire instead of the minimum NEC required #6.

What’s the advantage of using 2 rods on a simple residential service panel?

The NEC only requires one ground rod IF it has a rod to soil resistance of 25 ohms or less. So the electrician drives one ground rod. The electrician calls for an inspection. The inspector sees there is only one ground rod. The inspector asks the electrician to see the certified resistance test report proving the ground rod to soil resistance is 25 ohms or less... It’s cheaper just to install the second ground rod. Funny thing, if only one rod is installed and a rod to soil resistance test was done, and the resistance was say 100 ohms all that needs to be done is to drive another ground rod. No further testing is required by NEC.

The main reason for connecting the electrical service equipment and service neutral conductor to earth is for lightning protection. The lower the ground rod , (Grounding Electrode System), to soil resistance the better. IEEE recommends for commercial and industrial electrical services 5 ohms or less.


Earth-Resistance-Ground-Testing-Weschler.pdf

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The electrician installed 2 ground rods 6 feet apart

I got to wondering about this so I measured and the rods are 10' apart. 

I'm not advocating adding ground rods but here is my experience as an Eng Mgr over Test Equipment in an Aerospace Mfg plant.  We made product that operates in the 0-10 mA range.  So the test equipment must be very quiet in order to generate clean plots.  We started having some noise issues of say 0.5-1 mA which is enough to make the plots look bad on one of the test stands.  My test engineer suggested sinking a ground rod through the floor right next to the test stand so that the chassis could be grounded.  Our facilities mgr was not on board with that plan until we showed him that the building ground was floating at 500+ mA!  The ground rod worked.  To be effective the ground wire must be thick and short.  The ground rod must be near the equipment.  The ground was connected to the chassis only.
Adding ground rods just because may not be wise.  Proper measurement and analysis of the electrical noise should be done first and then determine the best course of action.  BTW- our products fly on airplanes.  Therefore, they are operating in the 0-10 mA range with no earth ground.

You probably already have it. It is called a water main.