SS: I just watch David video:
@16:18 I can see only one AC input breaker which is fine if you are feeding L, N, and Ground (as labeled on the terminals since this is US version is the modified ES version with new PCB that does not have N and Ground bonding), in this case with single breaker on L1 and no breaker on N (L2), if there is short circuit between L2 and case, it will depend on the house breaker to trip instead of the internal breaker (if they install one). Can you read the spec of that circuit breaker? May be GroWatt gets away with it since this model is not UL certified, so they do not install dual gang breaker.
I would expect the device that is fed by L1/L2 will require to have dual breaker, that is what I have to use on the US 240VAC products to meet UL requirement.