Power Supply question

[spectre03cobra]

I have a strange problem with my CNC setup that I noticed by accident. I'm using the Keling KL-350-36 power supply to run my Keling 4030 drivers. I mounted everything in an old computer case. I have the 120v AC going into the power supply, large prong connected to neutral and small to the Live... like in this video....and i have 120V running through the outside of computer case (well the whole thing I figure)! If I connect a voltmeter (or myself ) to the case and to ground I measure 120V. I'm not sure how this is happening. I have a couple tiny screws in the side of the power supply to keep it in the case, maybe that's it. Anyway it's not safe and not right, any ideas? Thank. I'm definitely not good with electrical issues.

[Al_The_Man]

I suspect you are reading stray voltage, the digital meter is nice as it is high impedance and does not load up the circuit you are testing, the down side is it picks up any stray signals, however your PC case and the PS case should be connected to earth ground so normally you should not be seeing any stray signals, only if it was ungrounded.
Two things to check, one is a continuity check from a know ground pin or connection to the case of the PC.
The other is to connect a load to the voltage signal you are getting and measure again, IOW, place a light bulb or lamp across the 120 you are reading, if the voltage is still there, or the lamp lights, you are in trouble and the source of problem should be eliminated.
If it is the case of the PS that has the signal, then it is not grounded.
Al.

[spectre03cobra]

Ok I'll try that. But I think it's real voltage. I didn't mention how I found it. I dropped something and leaned on the case with one hand and touched something with the other and threw the gfi circuit and I felt ac voltage. I just have to figure where the heck it could be from.

[Al_The_Man]

Your PC case appears to be ungrounded then and likewise your MB could have this potential to ground as the MB is generally at earth ground inside the case.
Your ground conductor from socket to PC needs checking and if necessary back to the panel, ASAP.
Al.

[spectre03cobra]

Well there is no mb inside the case, just my cnc electronics...1 power supply, 3 motor drivers, and a break out board. Im thinking there is no ground and I need to create one(?). I appreciate your help!

[spectre03cobra]

Ok, let me see if I have this straight. The case def isn't grounded like you said. Am I right in assuming the power supply isn't either, since I have nothing connected to ground on the diagram I linked to above, only to neutral and live. Would the best thing be to get a 3 prong cord and wire the ground to the ground, neutral to neutral, live to live. If that's the case how in the heck was my stuff even working.

[Al_The_Man]

As you mentioned Computer Case, I assumed this was where the leakage was taking place, regardless, sensing a voltage on a part of the system that should be grounded is not good.
I see we cross posted, you do not require a ground for the machine to work, you do need it for safety however, as shown by the strange leakage you are getting, my concern would be the nature of the leakage, IOW if it supports a current such as the lamp test, something is wrong other than a ground wire that is missing.
If the voltage DOES support a current then by connecting it to ground something will blow.
Al.