Yes, just as you describe, but the addition of a transformer allows you to reference the neutral to ground, therefore the hot swings above and below ground. It

Yes, just as you describe, but the addition of a transformer allows you to reference the neutral to ground, therefore the hot swings above and below ground. It’s a little more complicated than what I described, as your breaker box is 240V split phase, but the transformer outside your house allows for a ground reference at its center tap. If you have ever made the mistake of connecting a diode rectifier directly to AC mains, then grounding the negative output, you’ll blow a breaker. A 1:1 isolation transformer is still needed.