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The earth ground for our circa 1968 outdoor electrical panel in California is apparently a single maybe 8 gauge(?) solid copper wire running from a capped galvanized pipe driven into the ground (50+ years ago).

It runs from the pipe into the nearby wood in-outer-wall enclosure that holds the electrical panel, then vertically up through the top of that wood enclosure off to parts unknown within the garage and house. A same-sized horizontal solid copper wire is soldered to that ground wire; the other end is connected via split-bolt to a same-gauge copper wire coming out of one of the metal electrical box's knockouts along with cable (Romex?) with that copper wire seemingly bonded to the square D metal electrical box via the cable clamp, but continuing inside the box.

Recently I noticed that the stepped diamond-style clamp on the galvanized grounding pipe was corroded almost all the way through, so I will be replacing that with a new bronze clamp.

However, I will also be driving three 8 foot grounding rods nearby, connected with 4 gauge solid copper wire, and run to the electrical box's ground connection (I have not yet opened the box's front cover; it is a split-bus style panel). My city requires that buried rod grounding systems have a protective enclosure over the top of each rod to protect it and allow for inspection. My question, however, is how to run the 4 gauge copper connecting the rods. I would like to just have it exit the bottom of each flush-buried 8-inch-deep "flowerpot" style enclosure, and run bare (no conduit) underground about 12 inches down, perhaps with a green/white ribbon buried a few inches above it to warn future excavators. Running bare would improve contact with the earth, but is it safe enough?

Photos for background info - not directly relevant to my question.

Photo of 3 "main" breakers in split bus panel - 100A(to many 20A "sub" breakers), 60A stove and 30A dryer: enter image description here

Photo of 1968-era ground wires running past electrical panel - note split bolt splice on wire running into electrical panel. enter image description here

Photo of solder splice of wire from electrical panel onto earth ground wire running past electrical panel and on to parts unknown in garage/house. enter image description here

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  • Are you sure that your existing ground wire is actually "soldered" (silver-gray colored lump of metal joining the wires, not code-compliant), or is it "exothermic welded" (typically coppery/brassy colored lump of metal jointing the wires, is code compliant)?
    – brhans
    Mar 23 at 16:28
  • Cad welding is allowed but most will use irreversible compression fittings the split bolt would also be a violation, I should have mentioned that also.
    – Ed Beal
    Mar 23 at 19:14
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    It is real soldering, and it is a split bolt. I've learned enough in recent months from reading you folks' comments to realize both a not allowed now :) My information/guess is that that work was done in 1968; since I don't know where the "up and away" part of that wire goes and what it connects to, I am leaving it in place for now. My understanding is that adding a proper 4 gauge ground rod setup as well should not hurt anything.
    – Armand
    Mar 23 at 23:46

1 Answer 1

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The splice with solder is not allowed on the grounding system. I the max size required by code for the grounding electrode conductor in a residential building with driven rods is #6 copper #4 is required for uffer/ or concrete encased grounding system.

I have worked in locations that the AHJ required the full 8’ to be driven below the sod level and the connection point to be accessible I used a coffee can but that was back when they were metal.

As far as the conductor I normally place the rods as close to the foundation as I can the footing keeps some rods a few inches away from the foundation I just route the wire along the foundation I have not needed any additional protection in the past this may take a few additional inches of copper. The close proximity to the foundation keeps shovels from cutting it.

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  • Thanks. I am using 4 gauge because with the split bus the 3 "main" breakers are 100A, 60A, and 30A; I am not sure what the incoming service amperage is. Also, my understanding is that 4 gauge does not need mechanical protection under current code, so even if I run it in schedule 40 conduit instead of schedule 80 I should be OK. I like your near-the-foundation idea; we'll see where I can fit rods to avoid the shrubbery and roots by the foundation.
    – Armand
    Mar 23 at 23:57
  • Residential services 100-400 amps with driven rode only need 6 awg but bigger is ok.
    – Ed Beal
    Mar 24 at 12:30

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