Should the standard require physical isolation between energized circuits and normal users - ie the UL finger test? If so for which nanogrid types?
Most computer equipment is required to conform to UL/IEC 60950 standard that defines various hazards and require separation between hazardous conditions and non-hazardous conditions. It includes the following hazard limits:
- Electric shock - below 60V DC
- Energy - below 240VA
A 48V bus confined to a maximum current of 4A would be considered class III equipment and thus non-hazardous and eligible for exposed circuits like the inside of a PC, (PC with a conforming power supply for AC isolation). We could be more conservative than this and treat the 48V bus as hazardous. This would have implications for interconnect and connectors (if we ever get around to connectors).
Being more conservative might establish good habits for people unused to electricity. We wouldn’t want them to assume that all electricity is as safe as our LVDC circuits and so they should treat all exposed wiring with respect. It’s unclear what imposing this requirement would impose on the cost of standards conforming equipment.
Should the standard require physical isolation between energized circuits and normal users - ie the UL finger test? If so for which nanogrid types?
Most computer equipment is required to conform to UL/IEC 60950 standard that defines various hazards and require separation between hazardous conditions and non-hazardous conditions. It includes the following hazard limits:
A 48V bus confined to a maximum current of 4A would be considered class III equipment and thus non-hazardous and eligible for exposed circuits like the inside of a PC, (PC with a conforming power supply for AC isolation). We could be more conservative than this and treat the 48V bus as hazardous. This would have implications for interconnect and connectors (if we ever get around to connectors).
Being more conservative might establish good habits for people unused to electricity. We wouldn’t want them to assume that all electricity is as safe as our LVDC circuits and so they should treat all exposed wiring with respect. It’s unclear what imposing this requirement would impose on the cost of standards conforming equipment.