First time here, so be kind with me, if this not the right forum to post.

I have (maybe) experienced an electrostatic discharge (ESD) from a computer case some days before, and I'd like to hear your opinions on this accident.

A computer case at my work, was not plugged in the mains outlet and it has been approximately 5 minutes, that it has been unplugged and switched off. Only thing plugged in, was the 2 monitors through their VGA cables and I think there were both switched off but unplugged. The computer was a 7+ years brand name machine, with a 300 W, 100 - 240 V, 50 - 60 Hz PSU.

Upon lifting the computer case with both hands to place it beside the desk, accidentally it made contact with the cold heating pipe passing nearby on the wall. Suddenly some yellow sparks with sound occurred (similar to arc welding sparks effect). The same time, the circuit breaker turned off the power at another room of the building.

According to my knowledge, I did not felt something strange as being electrocuted or anything at all after this happened. The computer afterwards was only started if the power cable was unplugged and plugged in again, and the tech said there is no damage except form a mis-plaiced starting button cord.

My questions are: -What exactly happened there? Is it possible that have being exposed to any electricity risk for my health with afterwards effects? -Why does the circuit breaker turned off?

Thank you all for your time reading this, and looking forward for any opinion.

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    That isn't ESD. That's a seriously dangerous condition. Either your safety ground is hot and was shorting through the PC case to the pipe, or the pipe is electrically live and shorted through the PC case to ground. You need to have the building's electrician investigate. Now. – keshlam Mar 14 '16 at 13:37
  • It may be that the hot and neutral are reversed in the outlet as another possibility. I agree with Keshlam that it is seriously dangerous. + – Ed Beal Mar 14 '16 at 22:06
  • For confirmation: static (ESD) is a very high voltage though not much current. Hence the sparks, though brief, are high temperature and bluish-white, like lightning (which is ESD on a much larger scale). House current is much lower voltage, so cooler and will be more yellow/red as a result. – keshlam Mar 15 '16 at 2:06
  • 1
    Also, I'm assuming that one of the monitors, printers, or some other peripheral was still plugged in and providing the path to ground. – keshlam Mar 15 '16 at 2:07
  • @keshlam, according to your last comments posted 10 hours ago, you suggest that this yellowish occurred sparking was a static ESD discharge, caused by the house current? If I understood well, this comes in contrary with your first comment that this incident was not actually an ESD. – user3244633 Mar 15 '16 at 12:23

If it was just a tiny spark like touching a door knob after walking on carpet, then it's normal & harmless. If it was actually a flash, then something's either grounded to the plumbing & defective or a live wire's in contact with the plumbing.

Most likely, the circuit that the circuit breaker killed & is the problem circuit & must be fixed immediately as it could harm or kill someone.

  • Thank you @Iggy for your opinion on this matter. It was actually tiny sparks and a sound leaving a black mark on the pipe and computer case. If it is a live wire someplace in the building in contact with plumbing how come, I didn't felt anything as being electrocuted? – user3244633 Mar 14 '16 at 15:05
  • Definitely get an Electrician to correct the problem, it's a Very Big Deal if a circuit breaker tripped. You not feeling or noticing anything has to do with luck. The computer's wiring absorbed the shock just long enough for the circuit breaker to kill the power. Or, you were insulated from the computer by your shoes or the flooring. It's likely that you would have just had a very strong numbing vibration feeling & not any burns or literal skin blow-outs or exploded bones. But, you really-really don't want any of those things from your electrical system. – Iggy Mar 14 '16 at 15:17
  • I supposed I've been lucky, cause I felt nothing when this sparking, sound and a little burned odor occurred at this incident. I thought the same as you did, that this was not actually an ESD from the computer case, and I have informed my supervisor for this problem to getting fixed. – user3244633 Mar 14 '16 at 19:37
  • You might not have felt a strong shock because your body wasn't particularly in the path of the current. The current flowed between the PC and the pipe, and as you can tell from the sparks and burn marks, the area near their point of contact (and the air between them once they got close enough) carried the most current. You were perhaps holding the other side of the PC, which didn't get as much current. On the other hand, if you had touched the pipe with one hand and the PC with your other hand, then electricity could have flowed across your arms and chest -- a much more serious situation. – Shimon Rura Mar 14 '16 at 19:57
  • @ShimonRura, at that time of incident I have felt nothing at all. I was holding the computer case, left hand form the backside metal case, right hand from the front plastic panel leaning front to place it down on the tiled floor besides a wooden desk and the wall. As I can remember, cause it has been several days since then, I was touching with my body a wooden desk and the other side of the computer case, was touching the wooden desk leg. Maybe this can explain being lucky and get electrocuted at all? – user3244633 Mar 14 '16 at 20:10

@user3244633 in the days prior to polarized outlets if you plugged your metal toaster or mixer in wrong and rubbed your hand down the side you might get a "tingle" now take your shoes and socks off and it hurts. It depends on how well you were grounded. If your computer was unplugged but monitor plugged in you have a ground path if the pipe was hot. The more likely problem in my opinion is the hot and neutral are reversed so there could be voltage on the case instead of ground and the metal pipe was ground therefore the arcing.

  • If I understood well, you suggest that there is a hot and neutral cable reversed on the computer itself? So there is not any problem with the building wiring at all? – user3244633 Mar 15 '16 at 12:30
  • It could be the outlet or the computer. With a in expensive volt meter or a non contact voltage tester the outlet can be quickly checked. If the ground is below the 2 straight holes the hot should be on the right (the shorter hole) measure the voltage to ground or see if the right one lights up a non contact tester. If the left one lights the tester or 120V is measured on the left to ground the outlet is wired wrong. If the cord to the computer is original I doubt it is wired wrong. If the cord has a replacement end on it it could be wired wrong. I would check the outlet first. – Ed Beal Mar 15 '16 at 12:54
  • The computer cord is an original cord - no replacement end. At time of incident, the computer cord was not attached at the computer PSU at all. – user3244633 Mar 15 '16 at 13:10
  • But one of the monitors was plugged in and connected through there VGA cables. the outlet really needs to be checked outlet tester – Ed Beal Mar 15 '16 at 13:19
  • One of the monitors was plugged in and connected through the VGA cables same issue the outlet really should be tested outlet tester here is a cheap one that will test GFCI outlets also. – Ed Beal Mar 15 '16 at 13:22

You could die.

Seriously, do you not understand how close you came to being electrocuted? If, instead of picking up the PC with both hands, you had braced one hand on the water pipe and moved the PC with the other, you would not now be posting on Home Improvement SE about sparks and circuit breakers. Your family would be posting on Law SE about bringing a wrongful death claim against your employer.

You cannot use any electrical equipment in that room until the electrical wiring is properly repaired. Even after the repair, you should get a meter and go around your work area trying to find voltages between anything you might ever touch.

I see this question has other answers saying the same thing. I am adding my voice to the chorus because your situation is so frighteningly dangerous.

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