Edit: My rough location: Grand Rapids, Michigan, USA

There are a million questions and youtube videos on the topic, and I'm sure one of them clearly answers this question because it seems so absolutely basic, but I'm struggling to find a really clear answer. Most questions here on SE seem to be about exceptions to the norm, not the absolute norm.

I am putting in a 100A sub panel in a detached garage. I'm running THHN wires from my main panel in a conduit to the garage. I have 2 hots, 1 neutral, and 1 ground (EGC I think is the term? Equipment Ground Conductor?).

Because the garage is detached, I'm also installing 2 grounding rods (8 feet, > 6 feet apart). I have a continuous copper wire running from these rods into the garage. I believe this is called the GEC, or Ground Electrode Conductor.

So both the EGC from my main panel, as well as the GEC from my new ground rods, are both available to me inside the panel - I just haven't hooked them up to anything yet. What do I do with them?

Do I:

(Note I understand that in the sub panel the ground and neutrals are not bonded, I've removed the bonding screw)

  1. Connect both the EGC and GEC to the ground bar (my current guess / understanding)
  2. Connect the GEC to the ground bar, the EGC from the main panel to the neutral bar (this seems weird, but I read this somewhere I think)
  3. Ignore the EGC from the main panel, it's not needed, I only need the GEC to connect to the grounding bar.
  4. Something else?

Again, this seems like an incredibly basic, "step 1" of wiring a sub panel in a detached garage, so I'm hoping there is a very clear and obvious answer somebody can provide.

Thank you!


1 Answer 1


Great question, well formed. You clearly understand much of this. In my answer I'm not going use abbreviations so I can be very clear.

The 2 hots obviously go the 2 hot lugs, the neutral conductor goes on neutral bus bar, whitch you correctly isolated in the sub-panel. It's also proper (and required) to have the separate ground rods in a detached structure (you also got that right). You'll connect those to the ground bus bar in the sub, but ALSO connect the ground from the main panel to the ground bus bar. You got this!

  • 1
    Thank you very much for not only a clear answer, but a positive message as well. I've been a bit overwhelmed with all the little details I need to learn to get right, so the positivity is much appreciated!. Thanks again! Commented Nov 8, 2022 at 16:03

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