Inverters—both batteryless and battery-based—used in residential-scale RE systems must be listed to UL1741, as required by the National Electrical Code. Inverters listed to UL458 are designed for mobile use—for example, on boats and RVs, which are sometimes off-grid and sometimes connected to a power grid (for battery charging and to supply supplemental energy for AC loads, but not for selling energy back to the grid).

The two UL standards differ in how they handle AC system grounding: UL1741-listed inverters must allow for the neutral-to-ground bond to only occur at the main AC service panel. UL458-listed inverters have internal neutral-to-ground switching relays to allow for this bond to occur at the inverter if in off-grid mode, OR at the utility power service if it is connected to a utility hookup. Some inverters are listed under both standards, so you’ll need to read the installation instructions carefully. Many Internet sources market off-grid inverters as “UL-listed,” but don’t clarify the actual listing, so they may not be appropriate for residential use.

This may answer the grounding question.