COMPUTER CASE GIVES ME ELECTRIC SCHOKS

jaco5604

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Jun 13, 2012
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I JUST MOVED INTO A NEW HOUSE AND SUDDENLY MY PC KASE STARTS GIVING ME "ELCTRIC SHOCKS" 89 VOLTS SO I THOUGHT DAMM PSU BROKEN BOUGHT NEW ONE.... :sol: STIL SAME PROBLEM :heink: THEN I TRYED COMPLETLY UNPLUGING ALL THE CABELS (IT'S FULLTY MODULER) STILL SAME PROBLEM.. TRYED UNDPLUGIN ALL USB CABELS AND SO ON, STILL SAME PROBLEM... THEN I TRYED TURNING MY PSU OFF ON THE BUTTON AND STILL THERE WERE 89 VOLT-120 VOLTS IN MY COMPUTER CASE THE ONLY WAY TO COMPLETLY "OFF CHARCE MY CASE" WAS BY EITHER UNDPLUGIN THE POWER CABLE OR TURN OF THE POWER CONNECTER :cry:

I KNOW THAT I'T PROBELLY CUT BE A GROUNDING ISSUE BUT I LIVE IN DENMARK AND WE ONLY HAVE 2 PLUGS NOT 3 SOO ANY ONE KNOW WHAT TO DO XD



JACOBPETERSENHTX@GMAIL.COMSORRY CAPS TOO LAZY TO CORRECT (FROM DENMARK SORRY FOR MY ENGLISCH SPELLING)
 

shanky887614

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Feb 5, 2010
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1 sec are you sure you are confusing electric shocks with static?

if you have a metal pc case then you can get a zap as it discharges from you to computer and down the wall (psu,s are earthed and because they are screwed into case its earthed as well)




try leaving computer unplugged doing what you normally do and see if you get a shock off it.



if its defiantly not static then i would recommend you buy a good quality psu.



 

InvalidError

Titan
Moderator

Only problem there is that OP says he's in Denmark and has only two wire power outlets, no formal ground.

In principle, two-wire power distribution is supposed to be grounded through the neutral line but something may be miswired in the OP's situation and letting the live line leak power to the case.
 

whatsthatnoise

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Dec 7, 2011
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Sounds weird, since the issue persists with a new PSU.

Make sure that there's no "cable on the lose" that somewhere connects to the case. Aka if it's under charge all the time. If it only discharges once and than you can touch it without issues for some time, it's a static thing.

If it is static, you can use an anti-static mat and/or make sure you don't have your case sitting on a carpet and/or use anti static spray on your carpet. There are also anti-static wrist straps for you to use.

Or simply make a video of you getting shocked by the case all the time, upload on youtube and get rich and famous! Okay maybe not rich, but hey! ;)
 

MMXMonster

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Jul 6, 2010
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Sounds like a floating ground. I would have a person with electrical experience check your house power panel and make sure you have adequate grounding at the panel. Stray voltage may be coming from something else like a short in the house and when you touch the computer chassis you unintentionally become the ground.
 

whatsthatnoise

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Dec 7, 2011
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It could aswell be just himself getting charged, due to sliding around on his chair or something similar. Might check this if he doesn't touch his case after a while, but something else, heater, refrigerator, ...
 

InvalidError

Titan
Moderator

OP said he was getting voltage of 89-120V which implies he measured it with a voltmeter. You cannot measure a static discharge with a typical voltmeter since the discharge is too quick for measurement, the voltage would typically be out of scale at over 1kV and the discharge energy would get dissipated by the voltmeter's ~10Mohms input impedance very quickly.

Since the OP has no electrical ground, the case's ~120V 'charge' could very well come from PSU's input noise filter caps and surge suppression circuitry forming a capacitive voltage divider, charging the case to about half the line voltage due to the absence of proper ground. Since Denmark is a 220-240V country, that would be ~115V, which would be consistent with the OP's voltage measurements.
 

whatsthatnoise

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Dec 7, 2011
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I'm no pro at electricity, but I'm still not getting how the case could be charged like that. Especially since he replaced the PSU. I too live in a "2 pin, no ground" country with 220V and never managed to pull that stunt off.

Anyway, if you are right you better tell him how to ground his case/PSU.
 

InvalidError

Titan
Moderator

Does your country have polarized outlets and does your PSU have built-in surge protection?

live -> MOV (+ parasitic cap) -> ground <- MOV (+ parasitic cap) <- neutral

If the ground is not connected to anything internally nor externally, the case will float to some arbitrary voltage between live and neutral.

With polarized plugs, the unconnected PSU ground can be tied to neutral through the socket adapter or power cord. With a non-polarized plug, it is impossible to prevent people from plugging it backwards which could connect the case to live.

A downside of tying ground to neutral where no dedicated ground is available is that should something break the neutral connection, the case will be practically live, which is a potential safety hazard and the main reason why polarized plugs with dedicated ground is standard in new constructions almost worldwide.

As for what the OP can do about it, if his building does not have a usable ground in the existing electrical wiring, the next best thing would be to pound a 6-10' grounding rod in the ground (or whatever local electrical code requires), run a #8 cable from there to where he needs ground, put an outlet with ground there and tie the outlet's ground to the #8 grounding cable.