Interpretation on supplemental ground rods

[frizbeedog]

Here is the scenario.

Existing 100 amp overhead service being replaced to include meter base and feed to the existing untouched main panel.

As part of this installation a supplemental rod was installed in addition to the existing grounding system attached to the copper water main.

From the 05 Handbook commentary:

Section 250.53(D)(2) specifically requires that rod, pipe, or plate electrodes used to supplement metal water piping be installed in accordance with 250.56. This requirement clarifies that the supplemental electrode system must be installed as if it were the sole grounding electrode for the system.......

I agree with the inspector as well, and the reasoning behind this is the chance that that pipe electrode will be, or has been, replaced by plastic.

Quick story.

Me...newbie...thinking I'd be clever....did a service upgrade, and drove one supplemental rod. And I got a correction for it. Boss asks, "what's up with that?... I said, "It's supplemental."

He say's, "supplemental to what?"

Point being that I don't really know if the pipe in the ground on an older house has the pipe intact underground unless I dig it up and check it. Who's going to do that?

Drive a second rod and be done.

 

[goldstar]

As for the gas grounding we are now "required" to run a #6 bare copper or larger, or a #1 AL or larger, ground from the "point of service entry (where the gas line enters the dwelling) to the "point of electrical service entry" (where the Meter Base is). This is still required even if the gas line is entirely copper, or iron, or SS flex.

We used to do that here in NJ until the DCA officials decided it was ridiculous. We'd bond the gas line, inspector would inspect it, gas company would come in sometime thereafter and remove it. Mike Holt once published an article about gas lines corroding due to the bonding with electrical systems (I believe it was in Austin, TX) but I no longer have a copy of the article to post here. (sorry):roll:

As far as the add'l ground rod goes, I agree with the inspector but only because that's what the code says you are required to do. I don't have the test equipment to prove the 25 ohms so I just drive the add'l rod, and on a SEVERE angle, I might add. Every time you stick a shovel in the ground up here you hit a field stone. On the other hand, I disagree with this specific code requirement , but that's a whole other thread.:grin:

Me...newbie...thinking I'd be clever....did a service upgrade, and drove one supplemental rod. And I got a correction for it. Boss asks, "what's up with that?... I said, "It's supplemental."

He say's, "supplemental to what?"

Supplemental to the metalic water main bonding. Just a side bar to this thread, if there was an addition made to the residence and the footings had re-bar installed, that's a CEE and you would not need any supplemental ground rods