bengarland wrote:I have bought most of my equipment here in Japan so it's all 2-prong... even the equipment that I think might have 3-prong elsewhere, like my Orange guitar amp.
I was referring to equipment that has IEC inlets and a notice that says "This equipment must be earthed". If someone is selling those with IEC to 2-prong leads that is as dangerous as replacing a fuse with chicken wire. You would have no protection.
Do you mean equipment that has captive mains leads installed by the manufacturer?
I have no 3-to-2 prong adapters.
Good. They are not a solution.
So wiring up modular power using these MeanWell units is the first time I've run into the grounding issue
The purpose of the internal "frame ground" is so that if/when the PSU develops a mains fault that touches the cover it will blow a mains fuse immediately alerting you to the fact that it needs repair or replacement. That isn't completely foolproof, but it covers what the manufacturer expects might happen.
If you don't Earth the frame ground it might be sitting there faulty and catch fire or you may touch it and you won't find out until that happens, which may be too late.
If I understand correctly, RCD is the same as GFCI?
Yes, they trip when Live and Neutral differ by a small current.
It's described as an Earth Leakage Breaker -- 100V / 15A -- Rated Sensitivity 15 mA, Rated Operating Current 7.5mA
I mean, is this better than nothing at all?
Yes, but the difference between that and an earthed system is that the RCD only trips when the fault current happens and that may be caused by you touching it. You will still receive a shock, but it will be turned off fairly quickly. -ish. As long as the mains is coming from something powered on that breaker, if it were coming from elsewhere, say a dangling patchcable touches a frayed mains wire on another outlet, then sorry, game over.
Those devices have a test button, but all that tests is the trip. A real test would be to connect your equipment to mains live and then touch it and see if you only get a non-lethal shock. Fancy doing that?!
And going back to my original question, if I'm dealing with a 100V AC 2-prong input situation (potentially with the aforementioned "Earth Leakage Breaker") what's the correct (or least bad?) way to wire everything, compared to the schematics posted previously in this thread which are for a 3-prong grounded input?
The correct way of building non-earthed equipment is to double insulate all the circuitry. That means that you will have to invent a jack connector with a safety shroud. In other words you can't convert one to the other, double insulated appliances are designed from scratch and tested before being put on the market and you don't build an audio studio out of double insulated appliances.
Sorry, that's not the answer you want. I can only try to impress on you why you should not be cavalier about this.