Can second (non-service) panel GEC be the second GEC?

[Tan Da]

As I understand it, there should be a secondary GEC when the primary GEC is not connected to a UFer.
The house I saw today had only one GEC in the main panel and there was a GEC in the panel in the garage. Since there are two GECs in this system, is the requirement met, or does there need to be two at each panel?
I would think that it's fine the way it is, but wanted to get some more experienced perspective.

[Jim Port]

What type of electrodes were used? Was the garage attached or detached?

[Tan Da]

What type of electrodes were used? Was the garage attached or detached?

Detached garage. I assume rods, though I didn't dig down to see.

[Tan Da]

A slight moderation in terms, a GEC is the grounding electrode conductor, it's possible that code complaint a system will only have one. What I think that you're asking is about is number of the grounding electrodes. If you have a water pipe electrode then you need two electrodes if you have other types of electrodes then the number may vary based on the electrode type(s). So as Jim asked what kind of electrodes are you using?

Ah, so the same GEC could possibly be attached to two electrodes, and therefore I might only see one GEC terminating at the panel, correct? I was thinking that each electrode needed it's own GEC to the panel.
In this case I don't know what type of electrodes were used, as I didn't dig down to find them; I only saw the GECs entering the ground. I am assuming rods.

[Tan Da]

Yes there are several possible scenarios, separate GEC's to each electrode, one GEC to the first electrode then a bonding jumper to a second electrode, just one electrode, etc.

In some cases only one electrode is required at each structure so you may see only one GEC.

OK. Then I won't be concerned when I don't see two GECs on a home with no UFer.
Thanks Robert.

[Rich Goeken]

There's no one size fits all answer due the many variables. To know for sure you would need to identify the type of eletrode(s) used and take it from there.

Just a side issue. If there are two or more grounding electrodes, such as one in the house and one in the garage, and they are not bonded----due to soil or local environmental conditions (close to a sub-station as an example), you may have current flowing between them. This may cause "noise" in electronic devices and possibly a shock, should you somehow happen to get between the individual electrode grounds.