Hi, I was reading your inputs with interest and I would like to add this.
At present in ZA they are still formulating regulations. so in the interim I run my inverters thru a ready board with it own earth leakage.
they same as in the house.
I earth the inverter chassis to this as well.
Effectively the system now has its own earth leakage protection.
On the DC side, PV's and batteries, I only earth the PV frames to the earth in the house. This is purely for lightning protection.
also, depending on the inverter, the negative is being switched and is often the same point as neutral on the 220 side.
so to earth the DC negative you will effectively be causing the earth leakage to trip.