Enclosed vs. Open-Frame Power Supplies - Overdoing it?

[HenryT]

I would appreciate your views on the following.

We need a 60601-compliant low power (<100W) PSU inside the main enclosure of our new med instrument. Since power dissipation should not be a major issue at 50-60W, a 100% enclosed PSU could be used, instead of open-frame or enclosed with vent apertures.

It would be safer (more compliant?) for the operator and the patient, (e.g. against saline shorts) correct?

But fully enclosed <100W PSUs seem to be designed mostly for external desktop use, rather than mounted inside the enclosure of the instrument.

Are we overdoing it in searching for a 60W PSU without holes in the sheet enclosure? (like the external ones)

 

[cdewitt]

If your worried about fluid ingress I think the issue could be much larger than just the power supply. What about the AC inlet connection, power switch, fuses and other line side wiring and then what about the rest of what ever the PSU powers? If any of that gets splashed by saline what kind of faults could occur.

I'd work on keeping fluid out of the enclosure at what ever level of risk you expect to see for the application. I look at enclosures for a PSU as safety for people servicing the unit live and/or ways of meeting creepage clearance and safety grounding.