1

My house was built in 1929 and has gone through many rounds of plumbing/electrical upgrades over the years. I am replacing the galvanized pipes with PEX and I'm confident that I have planned appropriately for the plumbing part but I'd appreciate help with the electrical part.

Existing situation: the galvanized is bonded to the stub of original water main into the house because the water main in was replaced with CPVC at some point. (I've marked connection between the galvanized and the stub in red in the photo). The 200amp service panel is also bonded to the galvanized pipe as well as a grounding electrode (see photos below). Both wires seem undersized for a 200 amp panel and based on the age of the wire to the galvanized pipes is probably a remnant of the old service panel.

My question: when I install the PEX do I need to run a new wire from the service panel to the old water main stub to create a secondary path to ground? Or was bonding the galvanized pipes to the service panel a secondary path to ground in case the pipes became energized? (I apologize if I am not using the right terminology, I'm trying my best)


Photos of bonding of pipes to old water main stub. enter image description here

Photos of service panel bonding to pipes and service panel bonding to grounding conductor. enter image description here enter image description here

  • I take it all the galvanized is going away? – ThreePhaseEel May 11 at 17:38
  • @ThreePhaseEel Almost all of the galvanized is going away. There will be one run straight up from the basement to the second story bathroom. I am going to bond that to a pipe stub that used to run through the foundation to a hose spigot on the far side of the backyard (about 40' of metal pipe buried in the ground and I checked to make sure there is a connection to ground with a voltmeter). – Jonathan May 11 at 18:52
2

You will actually need a second driven rod to be safe with the metal pipe to the house being replaced. NEC 250.66(A) allows for #6 copper. Also, that rod is not fully driven. My jurisdiction requires the rod to be driven the full 8’. If you leave the old galvanized in the ground and it is in contact with earth for 10’, then you would not need the second driven rod.

| improve this answer | |
  • 1
    Personally I prefer the "dig a pit and drive it all the way from the pit" approach - more engagement with the ground, not a tripping hazard. I do have a hunk of PVC conduit projecting above ground on top of the first rod so I can easily find it if I ever want to. The next 4 are 3 feet underground before they were driven full depth, and the last one is a 6" well casing 100 feet deep. ;-) That one not being driven was the first thing I noticed in the pictures. I'm assuing form the question that the "old water line stub to the exterior" was abandoned in place as a ground. – Ecnerwal May 11 at 17:59
  • 1
    @ecnerwal deeper is better I agree and the well casing is better than a ufer ground from the measurements I have taken.+ – Ed Beal May 11 at 18:02
  • @EdBeal thanks! So if I ran a #6 copper from the service panel to the stub in the basement (which is in contact to the ground for over 10') I should be good? I guess another option would be to drive a rod on the side of the house but my question is, do the grounding rods have to be connected in series (like page 8 of this pdf: archives.corvallisoregon.gov/public/…) or could they both be individually connected to the neutral bus bar (like they are now with one wire running to the pipe, and one to the grounding rod)? – Jonathan May 11 at 19:01
  • @Jonathan -- either way works – ThreePhaseEel May 11 at 19:03
  • I agree with 3phase it is more common in series but both ways are fine. The sub itself could used if you used a compression crimp to join the 2 , the copper from that pipe connected with an non reversible crimp not just using the screw connections in the panel. – Ed Beal May 11 at 19:31

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.