alt Hacker NewsRight, but that's why I mentioned safety equipment. Your common DIN-mount UL-489 branch circuit breaker will be rated for the same trip current, same short circuit current rating (SCCR), but lower voltage. So you can use the same wiring and breakers as you might have with AC and your 48V battery bank won't vaporize the $5 hardware store toggle switch that somehow became a shunt.
I mean, most AC circuit breakers use electromagnets to trip on overcurrent (as well as bimetallic strips using thermal methods for sustained high current).
Electromagnets dont work for DC, so your breaker will never trip. For thermal protection, you need current, so that checks out, and it would make sense for it to be rated under 50V as thats considered the highest voltage thats not life threatening on touch.
PV Batteries in general have a very high current (100s of A) at ~50Vish volts, so I dont think there's a major usecase for using household breakers for them.
Im still not getting your point BTW, switches and breakers are two separate things, with different workings, and household (and datacenter) DC would be I think around 400ish V, which is a bit higher than the peak voltage of AC, but still within the arc limits of household wiring (at least in 230V countries).
The advantage of DC is that you use your wiring more efficiently as the mean and peak wattage is the same at all times. Going with 48V would mean high resistive losses.