Electric shock from network cable

Bobber0001Bobber0001
edited March 2010 in Hardware
Okay, this one's got me stumped.
Google returns no results for my search of "electric shock from a network cable" (nor if I exclude the word "a") so I really don't know what to do.

I've had my computer running on a wired network connection before, but have been running wirelessly for a couple of weeks since I've been missing a cable. I bought ten meters of "FTP 26AWGx4P CAT 5E patch cord cable" (pretty and yellow), but when I plug it into my computer and then the switch (from which two other computers are getting a working connection), the status lights don't even come on on either device.

Furthermore, when I plug the cable into my computer and touch the opposite end, I get a quite powerful electric shock - it's right on the border between a very powerful tingle and being somewhat painful. This happens both when the other end is unplugged and if I touch it while it's plugged into the router.

What can I do? Just buy a new cable? Did I in some strange way actually buy the wrong network cable?

Ed: The ends look like this rj_45_cables.jpg, and it's the metal casings on the ends that shock me.

Another computer is now available to me, so I tried plugging it in there. It still doesn't work, but at least it doesn't electrocute me.

Seems like I got the wrong wire, or at least a seriously faulty one...

Comments

  • ThraxThrax 🐌 Austin, TX Icrontian
    edited February 2010
    It sounds like you have a short in your case. That means some of the electricity that should be flowing to ground isn't doing so. The best way to fix this would be to remove your computer's components from the case and reinstall them, but first you might try connecting your PC to a different wall socket to make sure the current one is grounded correctly.
  • Bobber0001Bobber0001
    edited February 2010
    Thank you for the answer.

    I've never had my computers grounded and I've been using them (not the same ones) for almost two decades now. Is this really really bad?
  • ThraxThrax 🐌 Austin, TX Icrontian
    edited February 2010
    You've always had your computer grounded. :) It's the circular prong on the wall plug.

    It's not devastating, but it can have bad consequences.
  • Bobber0001Bobber0001
    edited February 2010
    There was of course no way for you to know, but I live in Denmark, where we are not as enthusiastic about grounding as you guys over there on the other side of the Atlantic.

    In fact, only two sockets in my house accept three-pronged plugs. One's in the bathroom and the other in the kitchen. Impractical as hell!

    I ran a wire from my computer casing to the heater, and the cable no longer shocks me, though I still can't get a connection. I tried with another cable and other ports, and I can confirm that nothing has been fried, so I think I'll just throw this cable out and get an ordinary cable instead, i.e. not foil twisted-pair.
  • kryystkryyst Ontario, Canada
    edited February 2010
    Those look like Power over ethernet cable ends. I've seldom seen any cat cables that have a metal casing at the end most are just plastic. While I'm sure it is a grounding issue I do think you may have got the wrong cables. Also if you were sending an electric charge to your router there is a very good chance you've fried that port, possibly both on the router and your PC. Sending an electrical current to a regular ethernet port it a great way to kill it.
  • Bobber0001Bobber0001
    edited February 2010
    As stated, I tested the ports and they're alright.

    The PoE suggestion is a good one, but I think the ends are due to the cable being FTP i.e. foiled twisted pair.http://en.wikipedia.org/wiki/Foiled_twisted_pair
  • ThraxThrax 🐌 Austin, TX Icrontian
    edited February 2010
    FTP, otherwise known as shielded twisted pair (STP), is designed to prevent electromagnetic interference for cables that must be run near heavy EMI sources. Doesn't carry a charge (usually).
  • Bobber0001Bobber0001
    edited February 2010
    Yeah, I know, I read the wiki article I linked.

    Edit: I just realized that I sounded like kind of a dick in this post, but seriously man, think it through: if I link a wiki article as a source or a reference, then I probably know what it says. I hope this edit makes me look less like a dick and not more like a dick.
  • RichDRichD Essex, UK
    edited February 2010
    Thrax probably didn't read the article you linked to as he is wikipedia personified. ;)

    I would still gut and reinstall your components to rule out a short of some kind.
  • Bobber0001Bobber0001
    edited February 2010
    Hah alright, fair deuce.

    My network adapter is on the motherboard, and the rest of my computer is working fine. Will it really change anything if I take out and reinsert my graphics card, CPU etc, and replug my hard drives?
  • ThraxThrax 🐌 Austin, TX Icrontian
    edited February 2010
    I knew you read the article. :) What I was trying to point out was that switching the cable away from STP won't solve your problem. You're still going to have voltage going places it shouldn't go.
  • Bobber0001Bobber0001
    edited February 2010
    Damn. And you're saying that I fix this by taking my computer apart and reassembling it?
  • ThraxThrax 🐌 Austin, TX Icrontian
    edited February 2010
    Because you have ungrounded equipment, it's likely that some component in your PC is touching a piece of metal in the case that it shouldn't to complete an electrical circuit. The ethernet jack is a prime candidate to carry that current because it has tons of wires, the Ethernet jack is metal, and so on.

    I think it's likely that things will work correctly if you reassemble your PC, which should incidentally clear up whatever circuit issue is going on. For extra safety, you can make a cardboard cutout the size of your motherboard to use behind the motherboard for insulation. Make sure you make holes for the little standoffs that you screw your motherboard into :).
  • Bobber0001Bobber0001
    edited February 2010
    Actually, my motherboard is missing a couple of screws, so I use duct tape and gum a few places already to hold it in place.

    I don't really have a normal case: I just bolted most of my components down on a piece of metal I found at the local scrapyard, using part of a broken case to hold part of the motherboard in place though. It's worked well for a while, and it saves on cooling! I'll look around for any contacts, but I've got electrical tape most places where I thought this could happen.

    Thanks for all the help!
  • RichDRichD Essex, UK
    edited February 2010
    Im intrigued. Got any picks? This is likely the cause you prob need to better insulate it.
  • Bobber0001Bobber0001
    edited February 2010
    RichD wrote:
    Im intrigued. Got any picks? This is likely the cause you prob need to better insulate it.
    I was not, uh, being serious >_>
    (Are you being sarcastic, or could you genuinely not tell?)

    On topic: I am realizing that the grounding issue may be bigger than it seems. I have been getting some (thus far) unexplainable static on my speakers, and by turning on my speakers and touching my computer case (yes I have a normal one) with the grounding wire I led from my heater (not a painted part of it!) I am getting some extreme static from my speakers. I think there's some major issue with either the wiring in my house or my power supply, and who knows, it may even be dangerous. I have asked around a bit, and quite a few people have suggestes that I have an electrician look at my house wiring. I think this is all I can do for now.
  • LeonardoLeonardo Wake up and smell the glaciers Eagle River, Alaska Icrontian
    edited February 2010
    I was not, uh, being serious >_>
    (Are you being sarcastic, or could you genuinely not tell?)
    No, I thought you were serious! Bobber, we used to have have a section here at Icrontic that featured "ghetto" (crude, rough, home-made) hardware. The "scrapyard" solution you described above would have been completely perfect as a ghetto hardware illustration. Seriously, I was really hoping you'd have photographs.

    I hope you get the computer short fixed.
  • Bobber0001Bobber0001
    edited February 2010
    Wow, that's really awesome. Now I also wish that my computer actually were like that. Maybe that's for a weekend project! Too bad the site section doesn't exist anymore...
  • RichDRichD Essex, UK
    edited February 2010
    Then what was the point in your post? We are trying to help you here. Sarcasm doesn't work well when it is written down. Look at the mods section and you will see much more extreme mods that what you describe above.
  • Bobber0001Bobber0001
    edited February 2010
    You know what, you're right: it was a silly and pointless post. Honestly I was just exhausted from trying to fix the problem. I know you're trying to help me and I truly am grateful for that, believe me.
  • RichDRichD Essex, UK
    edited February 2010
    No worries. OK so take all the components out of your PC (MB CD HD PSU etc) until there is just the bare case then put it all back together. You may want to use some better insulation. as Thrax said, the cardboard under the motherboard is a good idea. I have done it in the past (I think there are pictures over in the moding forum). The problem probably comes about because your PC is not earthed/grounded. Something inside the case is shorting against the case which makes the case live. Because the case is not earthed there is no where for the "charge" to go so when you touch the network cable you complete the loop to earth and get a shock.

    If you like crazy moding check out the cooling and moding forum. there is some cool stuff going on in there.
  • Bobber0001Bobber0001
    edited February 2010
    Alright thanks a lot man, I really appreciate it. When I get home this will be the first thing I do.
  • Bobber0001Bobber0001
    edited February 2010
    Okay this took quite some time. Upon inspection, I suspected my wireless network PCI card of maybe bridging the motherboard and the computer case, so I removed it.

    TO NO AVAIL

    Gah. This cable was the equivalent of two dollars. TWO DOLLARS. Maybe I'll just get a regular one when I get paid Friday.

    Edit: Yay, pictures! As you can see, I've grounded the case pretty well, the power cable for my computer doesn't support grounding (two pronged), and the cable is not a crossover cable.
    Edit2: Goddamnit imageshack, this doesn't work at all. Let me just fix this.
    Edit3: Please help me fix these images, it's not working at all :(
    Edit4: Finally, I'd used the wrong URLs somehow. Now it works.
    21022010677.jpg
    21022010676.jpg
    21022010669.jpg
    21022010667.jpg
  • SnarkasmSnarkasm Madison, WI Icrontian
    edited February 2010
    The pieces of metal around the housing 90 degrees from your prong positions are grounds.

    When you plug them into the socket, there should be a couple of metal tabs in the socket that contact the metal non-prong sections of the plug. If so, you're grounded. If not, you need to get your house rewired.

    Also, unless you've got some copper from that wire touching a piece of metal that goes uninterrupted to the earth, that's not grounding you. It looks like you've got it attached to a pipe heading that fits onto a plastic pipe - that won't do you any good.
  • Bobber0001Bobber0001
    edited February 2010
    Wow, it really does look like a plastic pipe, but it really is just a painted metal pipe which does indeed connect to the earth.

    All sockets in my apartment look like this:
    21022010680.jpg
  • SnarkasmSnarkasm Madison, WI Icrontian
    edited February 2010
    Mmm, sure 'nuff. No grounding there. Stylin' plugs, though.
  • Bobber0001Bobber0001
    edited February 2010
    Haha indeed, I talked too much about plugs for my own health when I visited the US this summer. Your plugs are so tiny!
  • LeonardoLeonardo Wake up and smell the glaciers Eagle River, Alaska Icrontian
    edited February 2010
    Your plugs are so tiny!
    Yeah, only 100-120V, that's why. It's very convenient for connecting many items, due to the compact size, but Europe's 220V delivery system is more efficient than North America's 110.
  • RichDRichD Essex, UK
    edited March 2010
    Thrax wrote:
    You're still going to have voltage going places it shouldn't go.

    This is the key point. May have earthed the case but that wont fix the problem. In the UK and probably US we use the earth as a saftey feature. You should never have any current traveling through the earth. It is the so that in the event that a piece of casing or some other metal part becomes live there is a lower resistance path to earth than through your body if you touch it. Most RCDs monitor load on an earth line and cut the power if the earth becomes live. By earthing you case you have not fixed the core problem and you have current going through components that shouldn't and you are in dager of damageing your hardware while your case is live. you need to correct the short which is somewhere in your case.

    Remove all components and connect the power to PSU then test to see if your case is live. this rules out a short from your power supply. then ad your components on by one and test as you add each one.
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