I upgraded my main circuit breaker today from 150amps to 200amps.

See my previous posts here on the same project:

What I missed is ground wire gauge. I had and still have #6 AWG copper wire which was enough for 150amps, but not enough for 200amps. So my inspection with my town failed - inspector has pointed me to this.

My copper ground wire goes all the way through basement to opposite side of house and connects to water pipeline there. I'd like to avoid upgrading that wire that goes in many hidden places (behind dry walls in the basement etc) to #4 AWG.. what I consider doing instead:

  • put a couple of rods 6 feet away from each other, but close to the MSP, like on this video - https://www.youtube.com/watch?v=t7FzUUqCdpI ;
  • upgrade to #4 AWG just the ground wire from MSP to these ground rods;
  • connect #6 AWG that goes all the way to the water pipe to these rods as well.

Would these be enough of grounding for 200 amps service? If yes, could somebody please reference relevant National Electric Code articles?

I now have to redo the grounding work, and request re-inspection, but I'd like to avoid rerunning that wire that goes around whole house to water pipeline. Driving a couple of rods into ground seems to me a much better idea, plus connect to the existing #6 AWG ground line as I described above.

What's interesting I already have one grounding rod and it's already in connection with that existing #6 AWG copper wire.. so I'd like to add one or couple more rods there.

When I brought up this idea to the inspector, he said NEC says if house has a water pipeline, ground wire has to go there. He was kinda opposing my idea of driving rods and making additional connections there (his argument was that AWG gauge for ground rods can't be more than #6 AWG). And again that's despite that I already have a similar grounding setup with a grounding rod.

Any help will be greatly appreciated.

2 Answers 2


Your inspector is wrong. You can always use a larger ground.

NEC article 250.66 covers this in depth.

In fact, the code handbook (an expanded code book good with explanations of what the code is requiring) has a great exhibit 250.30 which shows connections to grounding electrode systems. 250.66.A states the connections to rod, pipe or plate electrodes is not required to be larger than #6 copper.

if your existing connection goes from the rod directly to the service panel only #6 copper is required. If the system connects to a concrete encased electrode from that point (point of connection to the concrete encased electrode) to the panel #4 copper is required to the panel, but #6 or larger from your ground rod to the panel or point of connection with a concrete encased electrode is all that is required.

I use #4 solid copper all the time as most new construction has a connection point with the foundation rebar, and then a second method (driven rod) is connected. Since I already am using #4, I run the couple of feet outside and connect the rod with a listed clamp, all on 1 piece of wire.

It is OK to go larger but not required.

This method is code-compliant for up to a 400 amp service.

  • 3
    Most new homes have a "ufer" ground this is a connection to the rebar in the foundation the rebar has to be 20' minimum at 1/2" most rebar is tied with metal ties so your entire foundation ends up being a large ground plane, this is the most effective grounding method. Since the electrode or rebar is in concrete it is referred to as concrete encased. "Ufer" is the guy's name that developed this method of grounding back in WW2.
    – Ed Beal
    Oct 26, 2018 at 17:20
  • 1
    The existing #6 to the water pipe should be fine 1 additional rod would be needed however with so many water supply systems being changed to plastic I recommend installing 2 while you are doing it. I have found several homes that only had the single water pipe ground originally and the pipe had been replaced with plastic so these homes had no real ground scary. You don't have to up size the ground with rods and pipes only #6 is required, I just happen to use #4 because in almost all new work there is a ufer and that requires 4 since this is usually on the stem wall I run another 8-10' outside.
    – Ed Beal
    Oct 26, 2018 at 18:43
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    One thing you missed -- his water pipe ground/bond requires #4 to be Code for a 200A service, and that's what the inspector is plotzing about....even if the water pipe is no longer a grounding electrode, it still must be bonded for 200A Oct 27, 2018 at 3:22
  • 1
    Thank you @ThreePhaseEel - do you mind referencing this with references to NEC Article, perhaps as a separate answer? If I can't upgrade wire that goes to water pipe to #4, I must downgrade service back to 150amps to comply? Outside of NEC, electrically speaking if we'd leave water pipe wire as #6, and just add more grounding through additional grounding rods (+ connect to existing #6 water pipe wire), this should be somewhat equivalent to just water pipe wire upgrade to #6?
    – Tagar
    Oct 29, 2018 at 3:42
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    @Tagar -- you may be able to attach the new #4 wire to the old #6 wire at one end with the old wire disconnected and use the #6 wire to carefully fish the #4 wire thru to where it needs to go -- depends how they went about running the original wire though. (If the original wire was stapled in place, then this probably wont work; however, if it was fished through, then this has a chance.) See NEC Table 250.102 for bonding conductor sizing, and NEC Table 250.66 + NEC 250.66 for grounding electrode conductor sizing Oct 29, 2018 at 4:24

Right or wrong, all that matters is getting the approval of the inspector. #6 is a minimum for 200 amp service in most places, but using water pipes as the only ground has been abandoned by most.

After I installed my new 200 amp panel, the inspector made me remove my water pipe ground and made me drive in a 8 foot ground rod fed with #6 copper.

Since the copper water line ran for over 100ft under MY property to the main line, it was a MUCH better ground and in no risk of turning to plastic without my knowing. And by him requiring the removal from the water line, he now created an electrocution hazard for every water using fixture and appliance.

So AFTER he approved the single ground rod install and left, i simply bonded the water line to the ground rod as it should be for safety.

  • Wow that inspector was way wrong, the water pipe is required to be bonded. With a single electrode it needs to be 25 ohms or less that’s why we usually drive 2 because no testing is required with 2.
    – Ed Beal
    Jan 8, 2020 at 19:56

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