enter image description herePanel is currently grounded, using 6ga stranded, that goes about 10 feet or so and attaches to the galvanized water supply in the crawl space. I'm in the process of switching to PEX, BUT where the water line comes into the house, it is copper. Since the copper stub coming into the house is about 35ft away, can I still run a 6ga copper ground wire to it, or would I need to add a ground rod, also or? Ground rod would be about 10 ft from panel at the closest location, if used. Thank you.

  • How about a simple sketch showing where the different types of pipe are. ie, House galvanized (10') to Pex (35') to Copper.
    – Gil
    Mar 25, 2022 at 20:13
  • May vary by jurisdiction. In my area (Montgomery County Maryland) both ground to water pipe and 2 ground rods required, recently discussed with local electrician in planning for heavy up (he'll let me run the wire through the house per his instructions to save his time and my money but the panel work is all his) Mar 25, 2022 at 20:18
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    Keep in mind you can't splice a GES wire, so you cannot extend an existing GES. It has to be run fresh from the panel. So that's a factor: if you can up-cycle the existing GES to a ground rod, it'll save you having to buy a 50' long wire. Ground rods are 8' long. One ground rod will do if it passes a $500 impedance test which you can't do yourself, or else 2 rods (at least 6' apart) always pass. Mar 25, 2022 at 21:08

1 Answer 1


You'd need to do both

Since the copper water service line isn't being replaced with plastic, you'd need to ground to it, and since it can't be used as a sole ground, it needs to be supplemented with a ground rod. Note that in order to extend an existing ground wire, you need to use an irreversible compression connector (basically, a crimp that's large enough to join 6AWG wires) to join the new wire to the old one, and that might require a bit of tool rental.

  • Thank you. Just for knowledge sake........what would be done if no metal water pipe was available, just ground rod only, or? Also, I'm going to run all new 6ga solid copper wire, as I already have a 75ft roll of such. I appreciate the help. Thanks!!
    – Brad
    Mar 26, 2022 at 0:24
  • @Brad -- you'd need to drive two ground rods if you didn't have the water pipe electrode Mar 26, 2022 at 0:29
  • Gotcha.......ok.....Learning..Thank you!! 100 amp service too, btw
    – Brad
    Mar 26, 2022 at 0:44

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