Wiring Enphase Envoy S Metered

[du3ce]

I was wondering if anybody has wired a enphase envoy s metered. I understand how to wire eveything except there is positive and negative running off a single 15amp breaker according to the diagram?
Hard wiring the envoy s standard makes sense according the diagram is single wire running off a 15amp breaker.

[ButchDeal]

It is a double breaker for 240v

[du3ce]

Thanks Butch!