I see it slightly differently...
However, you've described bringing a PV DC circuit on or in a building to an inverter. So now that portion of the circuit that is on or in the building is controlled.
This is where don't agree. What I am saying is the Disconnect at the ground mounted array means there is no PV DC circuit on the building. The code specifically states that controlled DC conductors are either 1) PV source circuits, 2) PV string circuits, 3) DC-DC circuits between and at the output of DC to DC converter MLPE and , 4) at the output of DC combiners. It states from those circuits
TO a dc PV system disconnecting means (the DC disconnect between the array and the inverter). So the DC disconnect is the demarcation point between controlled conductors and non-controlled conductors, the way I read it. Of course it should be written more clearly and explicitly, rather than having to look at definitions. But we are not free to make up our own definition that is different than what is in section 100, so I don't think we can call the conductors after the dc disconnect as PV DC Circuit (PV System DC Circuit).
In other posts in this thread, the idea of circuit divisibility was discussed. NEC does not define "circuit" to my knowledge, but common sense suggests that circuits are indeed separate if there are certain devices between them, i.e. a Disconnect, an OCPD, etc. Just because current serially flows through conductors on either side of a disconnect does not mean they are the same "circuit", IMO. There can be different code requirements on one side or the other. So in general, I think it is proper to think of conductors going between PV modules, DC combiners, DC disconnects, and the inverter as being divisible into different "circuits" with potentially different requirements in the code, even though electrically with switches turned on it may be one big closed DC current loop.
In the end, I think we all agree that ground mount PV arrays with DC disconnect at the array means you do not need to have RSD devices like Tigo or other in that array or interrupting the DC home runs from that array, it just seems we disagree on why that is. The NEC could be improved on this section to clarify why.
![1722183012162.png 1722183012162.png](https://forums.mikeholt.com/data/attachments/36/36370-da43cf07da3f0603963e017340d4c917.jpg)