Ungrounded solar PV systems and transformer-less inverters

[will_shippee]

As a former solar PV installer the norm was to wire a negatively grounded system into an inverter with built-in transformer.

I'm now hearing that as long as the PV modules have double-insulated wires transformer-less inverters and groundless systems can be built (per NEC and John Wiles). This is apparently the way it's always been done in Europe.

Does anyone see issues with this new technique? I can see the benefits: less install time, fewer materials, cheaper/lighter/more relyable inverter, etc.

 

[gndrod]

Isn't solid state fantastic? Used to do this on comm satellites....