Is this possible? Fault currents are much more obvious at a higher voltage than lower, and I thought most RCDs would not be made to be sensitive enough to catch what might be a dangerous DC leakage.
Yes (not sure if there are existing products), because they work based on the difference of currents leaving and returning. (between 48V and 110V there isn't an insurmountable difference in detection capability needed)
Theoretically you should have zero leakage, and you should also trip on bigger currents (but a rack wouldn't use more than 10A maybe?)
Theoretically you should have zero leakage, and you should also trip on bigger currents (but a rack wouldn't use more than 10A maybe?)