We are selling a product using an AC-DC power supply manufactured by CUI INC (SDI24-5-U-P5 datasheet). We sold the product in a few European countries but we are currently talking with a new distributor in Japan.
The distributor recommends us to use a cable with a type A plug (cable which could be used) because most power outlets in Japan do not seem to have Earth ground.
The device which is powered by this external power supply does not have any metal parts (if that matters), it is independent (no other devices can connect to it), there is no chassis ground on the PCB either. The PCB can only be connected to the outside world with the power supply DC output.
Even though I believe that this AC-DC power supply is still supposed to work without Earth ground since some houses have terrible Earth grounding (if not inexistent), I have a few questions:
- Without Earth ground, does that only mean that the DC output of the power supply will be floating? Or do some filters or other things require the Earth ground to be effective for the power supply to work properly?
- Is there any safety concerns using such type A cables (with only two prongs) on a grounded AC-DC power supply?
I think that we could change this power supply to an ungrounded one in the future, such as SDI24-5-UD-P5 datasheet, but we would like to stick a bit with the first one since it was used for CE marking and that we have stocks. But obviously, safety concerns go first !