Rear panel is live

[CreepinJesus]

I was just unplugging some cables from my PC last night and noticed (slightly painfully) that the entire rear panel is live... as in electrically live icnic:.

I'm assuming this isn't normal, but can anyone point me in the right direction as to the cause? Faulty PSU? Bad case? A short somewhere?

Thanks

 

[pooch]

I would guess a short somewhere, first thing that would spring to mind are unused power cables from the PSU that have maybe been tucked away eg behind the board. It could really be any number of things I would recommend checking all cables and plugs for damage and switching it off to work on it
If you are not electrically minded it would be a good idea to get professional help.

 

[Sub Styler]

This is worrying as a live case should instantly short to earth and trip your fuse, well for 3pin plugs anyway, not sure how it works in 2pin countries.

In addition to what pooch said.

The rear IO shield I am assuming you are referring to (which would pass current through the rest of the case aswell since metal is conductive that way). Is it lined up correctly or jammed in, if it is forced to fit between the case and still line up with the motherboard you may require different size standoffs for mounting the motherboard to the case? Do you have a multimeter for determining the voltage, if so put the L1 on the IO shield and L2 into one of the middle holes (black cables) on a molex connector.

 

[badger906]

Could be static discharge? Depends if it was still live after it grounded through you? But bet you didn't try a second time!? Lol

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[CreepinJesus]

It was still live after a shutdown, but not after I'd turned off the PSU and unplugged it. It's strange that it's not earthing, though.

I think it's also going through the case, as it was the screws on the back that got me, as well as the rear IO panel. Most of the case is painted though, so it doesn't zap me from the front/sides/etc..

For investigating this weekend - I have spare case around anyway which I was going to compare noise levels in, so we'll see how that goes.

Thanks for now...

 

[Comp Cmndo]

...It's strange that it's not earthing, though...

Not strange at all. It's a Ground Fault.
Residual-current device - Wikipedia, the free encyclopedia

Try a different wall receptacle, If no change, try a different wall receptacle on a different circuit (i.e., different circuit breaker). If no change, it's likely a defective PSU.

You can test receptacles with one of these:

 

[badger906]

just had a thought, are you using a HDMI cable as a monitor lead? as (i know its a completely different device) my new style xbox 360 is live all around its metal bezel, when plugged in using a HDMI cable. Does not happen with component leads.

 

[Sub Styler]

There seems to be 2 faults,

1. There is a short to ground somewhere in your system (could be anything from a damaged cable to a faulty PSU (most likely), or any other component that screw to the case (just about everything).

2. There is a grounding fault, a short to ground should trip the fuse (RCD) if this isnt happening then it could be the PSU, cable or wall socket.

The chances of having two faults are much lower than the chances of one faulty device. The only common denominator between those two is the PSU and therefore this is most likely to be your culprit.

 

[CreepinJesus]

just had a thought, are you using a HDMI cable as a monitor lead? as (i know its a completely different device) my new style xbox 360 is live all around its metal bezel, when plugged in using a HDMI cable. Does not happen with component leads.

Yes, I am. HDMI to the TV. I've had the PC turned off for a day or two now, but now that it's back on there's no charge on it so far. Maybe just a build-up from somewhere?

 

[badger906]

Maybe moving the case around has stopped the short I'd their was one, but molex/serial leads would be hard to short. Keep an eye on it, but preferably use a volt meter not your digits!

Still worth buying a socket/plug tester. They are reasonably inexpensive and handy to have.

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[Sub Styler]

Badger sounds right it may be an intermittent fault that has been resolved be moving it.

Static will build up on certain surfaces (shouldn't in a PC case as it should earth through the PSU). The only place an electric current can build up is in a capacitor or similar component. I wish you luck with your case, perhaps wear insulated gloves when changing cables or use a multimeter to see if it's safe before hand. Of course if you have any little-ones in the house I'd advise having it PAT tested, this shouldn't cost much for a single device.

 

[HammerHead]

Grounding

If the case is hot to ground I would think the wall outlet is not functioning to ground. Do You have a three wire 110v system? If you do the case should drain via the plug and possibly (more than likely) trip a breaker (fuse). If you are not familiar with electric service the receptacle tester mentioned is a good tool to determine if your ground is working.

 

[Comp Cmndo]

If the case is hot to ground I would think the wall outlet is not functioning to ground. Do You have a three wire 110v system? If you do the case should drain via the plug and possibly (more than likely) trip a breaker (fuse). If you are not familiar with electric service the receptacle tester mentioned is a good tool to determine if your ground is working.

Probably Hot & Neutral are reversed or Ground is missing. This won't trip a standard breaker, only a GFCI breaker.