Help with power supply wiring question. I just received the following power supply and I am noticing only 2 wires for power connection to the mains. I was expecting 3 wires to connect the live, neutral and ground wires. Am I missing something? Should I connect the live and neutral wires to the terminals and connect the ground the wire to the case? There is no information available regarding connection the mains power.
Perhaps the screw and pad on the PCB all the way to the left is gnd. Chk with meter.
I have two of those PSU’s. That pad is indeed connected to the ground of the case. It is where I connected ground wire, however they did not intend for this to be the ground, it just happens to work as one.
That’s what I would do.
Connect the ground wire to the case. That’s correct.
I got the exact same setup. I never grounded mine. It works. I got the unit screwed down to a piece of wood and no plans to touch it while it is energized either. China power! I really should recap the POS before it blows up. I’ve heard they have a tendency to do that.
You should ground the case of the power supply and all the metal housings. This is the save way and you live longer 
@Peter_Spiess I’ve been working with line voltages for 40 years now. How much longer do I need to do this stuff before it dawns on you that I know what I’m doing?
Paul, why are you so angry? Here in old Germany we will work on the save side 
It is your thing as you will work.
@Paul_Frederick No, you don’t know what you’re doing. You don’t know, for example, the quality of the PSU, and even if you did, you can’t guarantee no live wire will ever touch the casing.
Either you isolate the casing in such a way that you guarantee you can’t touch it or (better yet, and) you connect it to ground. You might want to risk getting a good jolt yourself. But it’s irresponsible to suggest it’s ok for others to do the same.
Grounding metal parts that should not be energized is a requirement in several standards for a reason.
Ya feeling lucky?
Another consideration - Static charge
An exposed grounded wire in your vacuum tubing will reduce the static cling. I mill plastic and the dust will attract to the static charge created by the air moving over the plastic tubing.
Something Weird is going on. I have the RioRand PWM controller connected Amazon.com. (See link). The controller is rated at 160V. When I send a M3 S8000 command using tinyg the controller shuts down and the light turns off. I’ve checked the power supply output and it shows no DC output. I can reset the power supply by unplugg and plug back in. I am stumped why it’s doing this.
@Gato1 that’s what I did. I isolated the PSU on an insulator. I’ve no reason to touch it ever either. If the need were to ever arise though I simply flip the power switch off first. I can’t count the number of times I’ve seen grounds fail now. It is pretty common. But you keep relying on them being good. Here’s to hoping your luck holds out.
I would find an equivalent load for the supply to test it. Power supplies
can go into “fold back” mode which I suspect is going on.
See the reviews:
fold back vs current limiting
http://www.edaboard.com/thread237501.html
probably not much help, but more insight
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@Paul_Frederick crazy, absolute crazy, you made my day 
Have you ever heared about electrical savety?
@Peter_Spiess I cannot say that I have http://i.imgur.com/By1FagV.png
Guys can we stay on the subject please. Why does my power supply output voltage go to zero when my PWM controller starts my motor.
@Rob_Mitchell1 troubleshooting is a process of reduction and there’s just too many variables for anyone to give you a definitive answer with the information you’ve provided.
http://www.catb.org/esr/faqs/smart-questions.html
What you suggest is exactly right. Safety ground the case.
After looking at the customer reviews:
It made me wonder about the P.S.
In general, to troubleshoot a switching power supply (not like the old linear power supplies) you need an appropriate load to simulate the conditions of your motor system.
To be really accurate, it may need to be inductive, but a resistive load of the same power requirements may suffice.
I have used high wattage resistors for a load bank or something as convenient as filament light bulbs of equal value. For example a 25 Watt appliance bulb for an estimated power requirement of 25 watt load. PLEASE - THIS IS ONLY AN EXAMPLE your situation may be very different.
This would give an indication that the power supply is up to the task.
Testing should be done with an expendable simulation because you don’t want the magic blue smoke to be released from your expensive equipment.
Like what Paul said there are too many variables to give a simple answer.
Power supply issues can be more complicated than you may think. Expensive bench supplies will guarantee
the on voltages don’t have spikes and overshoots . . . that some equipment is sensitive to. Hope that helps to some degree, Jim