Question PC shocks, please suggest me a grounding solution.

Jun 2, 2019
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Hello error, i just joined the forum to ask this question. Hopefully I'm following the forum's rules properly.

So I used to have a cheap HEC PSU that ran well for 5 years, but I always had the issue of getting shocked through any scratched/unpainted part of the case or through touching any USB or anything in the rear IO or even the front panel sockets. Then I decided to upgrade it as I started to recognize how critical a PSU is to the system and how serious can a failure be, and I thought an upgrade might solve this issue. Turns out not. I upgraded to a Corsair RM650x (I think I chose a good PSU, right?) and the issue still persists to this day, hell the shocks are now even more intense than the old 400w no-name PSU.

However, I can see how improper wiring can cause such issues. And the problem is that I have absolutely no ground wiring in my country (it's only existent in companies, universities, etc.) so I cannot even find any ground rod near my building that I can ground my outlet to. So, is there any possible solution for this? Even if it's any "ghetto" grounding solution I can do for now? Honestly I cannot deal with being unable to connect any of my valuable devices to the PC's USB for 8 years since I started building my PC.

Any help would be MUCH appreciated. Thanks in advance.
 

AllanGH

Estimable
Mar 10, 2019
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Drive a 2 meter ground rod into the ground, closest to the outlet that you are using for the computer, and clamp a ground wire to it, and run it to the outlet, properly connecting it, according to your local electrical codes / regulations. You may have to hire a professional to have this done both correctly, and safely (although the first implies the second).
 

Satan-IR

Honorable
That's the right way mentioned above.

However, doing proper ground rods might not be easy to carry out depending where the computer is, which floor etc.

A heating radiator (if available) can work too. Ground the case using a wire to a non-painted surface of the piping.

Do this as a last resort if you can't implement a proper ground/earth rod setup.
 
Jun 2, 2019
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Unfortunately both options are not available as I do not have a radiator in my apartment, nor an installation of a ground rod is possible since I live on the 3rd floor and such a job would be insanely expensive where I live. However, is grounding a single outlet into the room wall using a 6 inch rod a good idea (would it even work?)? Even if it's not "perfectly" safe, I don't think having a PC that shocks is any safer, amiright?
 

AllanGH

Estimable
Mar 10, 2019
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That would depend on local regulations (plumbing Earthing), but a cold water pipe is a decent option...BUT you really should test the potential difference between the PC chassis and the pipe before attempting to use a cold water pipe as an Earth. If that chassis is 50V+ above Earth, you could cause issues by passing fault current through the plumbing.

If the PSU is very old, it may be the cause of the problem, right-off. Do consider taking out the PSU and taking it to a computer shop for a quick test.
 

Karadjgne

Titan
Herald
  1. Yes, the Corsair RMx is a Very good psu.
  2. Cold water grounds have inherent issues. Mainly electrolysis which can/will affect any copper piping/fittings and what you end up with is after a while, that copper gets pinholes and starts to leak like a sive. Once it starts happening, there's no cure, the copper is eaten away, only full replacement with cpvc or pex will cure it. Your landlord would have a collective fit after replacing the plumbing in the entire building.
  3. Any 230-250v circuit, like the stove, dryer, window ac unit, sometimes even the water heater will absolutely have a ground, many branch circuits also contain a ground, it's either cut off or just stuffed in the back of the box, you'd have to look.
  4. The best way without doing any McGuyver hacking of the electrical system, is the most expensive for you personally. That's a APC/UPS of appropriate size. It creates its own ground outputs by use of the battery. You'd need a line interactive, pure sinewave type.
  5. While I don't recommend it, I've seen ppl hijack a plug circuit with a GFCI outlet, they'll connect the ground and neutral together to make a 'false' ground, enough to get the GFCI to work correctly. I'd definitely recommend against doing that with a regular outlet, there's no back feed protection like a GFCI will somewhat provide.
 
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Karadjgne

Titan
Herald
Hmm, hate to disagree, but it does. In a bad way.
Water bonds are lethal to copper pipe. Been dealing with that for years when ppl call the shop cuz they are getting shocked in the shower lol. A seperate grounding conductor is fine, no worries, but can't use a water bond as a grounded conductor.

In layman's terms, its OK to ground a copper pipe to the service (if that's to a ground rod) but don't use the pipe in the bathroom to ground an outlet.
 
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AllanGH

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Mar 10, 2019
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Water bonds are lethal to copper pipe.
Interesting.....I have Cu plumbing that has been grounded for more than 40 years without leaks. I have to opine that the fact of a safety earthing to a pipe isn't the primary cause of that particular failure mode. After all, fault current is merely a transient event.

At any rate, the root of this particular issue may be the failure of the "Y" capacitor within the PSU, itself.

View: https://imgur.com/a/1uK1phB

If the "Y" capacitor (indicated in the top-center of the above schematic) is shorted, you will have constant fault current flowing in the Earthing conductor. In this scenario, your breaker will constantly trip, indicating that the PSU is not safe to use until that particular capacitor is replaced. Practically-speaking, replacement of the PSU would be your best solution.
 
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Reactions: TJ Hooker
  1. Any 230-250v circuit, like the stove, dryer, window ac unit, sometimes even the water heater will absolutely have a ground, many branch circuits also contain a ground, it's either cut off or just stuffed in the back of the box, you'd have to look
This is not true. What is supposed to have and what it does have is different. Also for instance Thailand didn't get Earth until 1996 - when a Law came in, but still not enforced.

If you can access your Fusebox - you can open it and see if it actually has an Earth Wire. Or if they have done a link between Earth and Neutral
 

Satan-IR

Honorable
It is a matter of regulations, the construction code if you like. It's not the same worldwide.

If it's there in the regulations as a mandatory prerequisite for the city council/municipality office or housing/construction authority etc. to issue a permit to start/carry out construction or to certify that a building is built and facilities and water and electric are installed according to code and the code is actually properly enforced you can asume it MUST be there. Otherwise there's no must.
 
The problem is the case of your PSU. The metal enclosure is connected to earth ground, which is connected via capacitors to the mains voltage, as additional filtering of switching noise. Ideally, they should not be run without earth connection.

Long story short, you need to insulate your psu case from touching your PC case, which is consequently connected to all usb ports, i/o headers, etc.

It sounds stupid, but try wrapping your PSU in plastic/electric tape, and use plastic screws (or non at all) when installing it.
 

TJ Hooker

Illustrious
Herald
FYI you can get shocks from your PC even if it is grounded. Although in that case you may think of it as the PC receiving a shock from you (given that you have static electricity build up and discharge into the PC), but the effect is the same.

I have to opine that the fact of a safety earthing to a pipe isn't the primary cause of that particular failure mode. After all, fault current is merely a transient event.
Agreed, during normal operation the DC current on your grounding wire should be ~zero.
 

AllanGH

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Mar 10, 2019
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My mind doesn't want to let go of this, for some reason...probably because I enjoy finding the root cause of a problem.

Nevertheless, a few thoughts:

The use of "Y" capacitors is currently under discussion by the relevant governing bodies, in the United States; precisely because, if they fail in a shorted condition, they can conduct mains voltage to the PSU case, and thereby into the chassis of the computer system in which it is installed. This is, of course, a violation of several existing safety regulations.

The use of "Y" capacitors, without secondary safety devices in place, is likely to be prohibited in future SMPS designs.

I'm not saying that this is the exact failure in this situation, but the symptoms do fit quite well.

It may be that the most expeditious solution would be to open the PSU, remove the "Y" capacitor, and test that component for a shorted condition.

The capacitor can then be held-out of the PSU, and the PSU reassembled and tested for the presence of voltage on the PSU case. If there is no voltage present, then the situation has been resolved well enough to reinstall the PSU to the computer case and put the computer back into service. If there remains voltage present on the PSU enclosure, the PSU can be further diagnosed to determine how mains voltage is appearing on the PSU Ground / Earth bus.
 

TJ Hooker

Illustrious
Herald
@AllanGH where have did you read that Y caps may be phased out in the US? With regard to safety, Y caps are designed to fail open. But even if they do fail short, the energized case would be protected either by chassis grounding or a GFCI (at least one of which has been mandated by US electrical code for decades).

With regard to this thread, it seems unlikely that both of the OP's PSUs happened to have the exact same failure (Y cap failed short).
 

AllanGH

Estimable
Mar 10, 2019
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Either I did not see that two PSUs were involved, or I did not remember that fact. I apologize for overlooking this.

The documents that I read in the past couple of months, do address facts that mirror my own findings in diagnosing failed SMPS assemblies, namely that, despite their intended purpose, "Y" capacitors do, in fact, fail to a short, under certain conditions--namely when installed in an environment where inadequate safety Earthing is provided. Under such conditions, the absence of adequate Earthing presents a unique danger to personnel--by design.

I review volumes of data in any given week, and cannot recall the exact source of the discourse that I read which raised this legitimate concern. I will search back through the documents that I have viewed, some which have been saved locally, and see if I can determine the agency from which the original document was derived.

You will recall that "X" capacitors exist between Line and Neutral to reject differential-mode noise on the mains input line; and "Y" capacitors are the attempt to reject common-mode noise on the mains input line, by tying either the Line or Neutral conductor to chassis ground--ideally, the selected conductor would be the Neutral conductor. However, no secondary safety device (which would tolerate common-mode noise suppression currents, yet open upon full fault current flow) exists in series with the "Y" capacitor.

Please additionally recall that my exact statement was: "The use of "Y" capacitors, without secondary safety devices in place, is likely to be prohibited in future SMPS designs."

The discourse documents that I have read do not propose the outright elimination of the "Y" capacitor as a means of rejecting common-mode noise. They raise the objection to "Y" capacitors being the only series element in the common-mode rejection circuit. Inserting a device, such as a polyfuse, or a simple fusible link, would satisfy the goal of common-mode noise rejection along with the goal of equipment safety; and that should have been designed into SMPS implementations from the very outset.

What will likely issue-forth from such attention is a probable requirement that an additional safety device exist in series with the "Y" capacitor, for those occasions when the metalized paper/film layer cannot clear a short-circuit condition, or when ceramic units follow their inclination to naturally fail in the short-circuit condition. It may well be that the recommendation will be handed-down that ceramic units are disallowed for such uses, because of their natural tendency to a short-circuit failure mode.
 
Reactions: TJ Hooker
As mentioned above, it's not likely that two PSU both came with shorted Y - caps. There's also no point in discussing the future of Y-caps here because it doesn't benefit the OP or this thread. Also, the schematic posted above is not employed in any power supply over ~75W, due to its poor efficiency.

This picture shows what a Y capacitor refers to, and why it is causing the shocking issue.


C1,C2 are Y capacitors, with one side connected to earth ground. In a PSU, earth ground is also connected to the enclosure. If the earth ground connection is not made (i.e. no ground present like in OPs case), the earth ground node in the system will effectively be at half the grid voltage, as the capacitors form a voltage divider. As this earth node is also connected to the metal enclosures, every time the OP touches the case, they get shocked with a voltage equal to half the grid voltage (of course the capacitors also provide some impedance so the current is not high). This is exactly why every switch mode power supply with an earth ground metal enclosure is not supposed to operate without the ground connection.

As I mentioned above, the way to solve this issue in the OPs case, assuming they cannot get a proper earth ground connection, is to isolate the metal enclosure of the PSU from touching any other metal part of the case.
 
Based on my experiences in Qatar, often even a rod driven 2 meters into the sand won't cut it, as the ground is sometimes too dry...; some had to resort to 4 meter rods and/or a trickling water supply to constantly wet the physical dirt/ground in that area for the dry dirt to allow functioning as a true 'ground'...
 

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