I fail to see how you can perceive a current source that will not falter as “no problem”!
This is precisely why I posted the warning about DC, it’s a perfect example of why things can go seriously wrong.
So we have a single PV panel that can happily kick out ~250watts of power into a dead short all day long, the fact that most PV panels will be most likely connected with suitably (over?) sized cable means the weak point in the circuit is quiet possibly the point of short, but even that’s not definite, the short could be able to carry the current and then the heat becomes the problem.
Based on your assurances of low voltages, low currents and micro inverters being “no problem” a user could disconnect their microinverter from the AC side and stuff their hand somewhere it shouldn’t be, if for example their wedding ring (for example) shorted out the DC, this would become a 250w heater element wrapped around their ring finger. Have you seen the damage a 30w soldering iron does to flesh in a few seconds, let alone 250W until the sun goes down.
Going back to my example involving the alligator saw, the panels were fine pumping power into a short and the cables were ok with transferring that energy, even the saw blade managed to withstand the current, but the whole tool got so hot, so fast, the guy couldn’t remove the tool, the blade got so hot it ignited the wooden walls around it, had he not smashed the saw out with a scaffold pole, the saw blade might well of hung in there until sundown. That IS the problem with an unprotected power source.
The act of installing protection like a fuse or circuit breaker is to build in a known weak point so that it becomes the point that burns out or trips, not the poor sole (or equipment) hanging off the the other end of the cables.
My original comment was purely to say that extra precaution needs to be observed with inverters as the DC side is more troublesome BECAUSE it is an uninterruptible power source with no protection or isolation (at source) AND because it is often misunderstood that low voltage/current is “safe”, It would only take a few watts of power delivered to the wrong place to destroy a RPi (or even an expensive laptop whilst commissioning a connected monitoring device, for example), it depends on what your concept of safe is I guess, I wasn’t concerned about damaging the PV panels or the wiring from them. I was concerned more about what else might be completing the circuit, even a quick but unexpected bang or flash could make someone fall off a ladder or smash their head against something.
I once had to go and inspect/assess the damage done to a brand new Saab that had a 10A fuse fitted (in error) to a 3A circuit when a radio was fitted and the wiring was crushed when the radio was pushed into the dash. The fuse didn’t blow, but the wiring rated for 3A got so hot over night due to the partial short that it set light to the floor mats and slowly smouldered away until the staff found a smoke filled burning car the following morning,
It doesn’t need to be a large current source or high voltage to be a problem, that’s the point.
Even the fact it’s power is derived from the sun cann be a problem, disconnect the DC cables and put them to one side at night when they are dead, when the sun comes up the following morning when your not about the DC cables become live “unexpectedly” (unplanned might be a better word) and start a fire whilst your out or in bed etc