[mattpallissard]

> My understanding is that neutral goes to ground at the substation

Close. It's at the transformer.

North American "split phase" power has the neutral center tapped into the transformer winding. The two 120v lines are phased 180° from each other with respect to neutral. Line to line gets you 240v, line to neutral is half that, 120v.

Downstream in the breaker panel itself, the grounding conductor (ground) and grounded conductor (neutral) are bonded at the panel. The ground wire is basically just an alternate path back to the box.