How concerned would you be? External HD + static electricity shock...

Discussion in 'Mac Accessories' started by edcoche, Oct 30, 2011.

  1. edcoche, Oct 30, 2011
    Last edited: Oct 30, 2011

    edcoche macrumors regular


    Nov 2, 2007
    Hello everybody! Thanks for taking a look at my post.

    I have a question about static electricity and an external HD. I recently bought a WD My Book 2 TB external HD for my 4 year old Blackbook. I'm now using Time Machine to back up all my data so I can recover everything if my HD ever crashes again (argh! :mad:)

    Anyway, while using the My Book drive for the first time while it was about 65% done with the initial Time Machine backup I touched my Macbook and my finger accidentally transferred static electricity to my computer which still kept it functioning fine however it caused an error with the backup process and it ejected the My Book drive before the Time Machine backup was compete. I gave it a few seconds then I reconnected the external HD and reformatted it and successfully backed up the 190 GB of content on my computer's HD.

    So, the question is, how badly have I damaged the My Book backup by having this happen? Is it mostly likely fine and I dodged a bullet? Would it be worth the time in taking it back to the store and exchanging it for a new one? Am I being overly concerned here? Thing is, I probably spent 60 hours recovering all the data from backup CD's and I really want to avoid having to go through that again.

    Any advise/input is GREATLY appreciated.

    Thanks again for taking the time to read this thread.
  2. Prodo123 macrumors 68020


    Nov 18, 2010
    Did you know plastic doesn't conduct electricity?
    Did you know reformatting that hard drive means wiping all data from it and starting the backup from scratch?
    Most likely that's a faulty drive; get a replacement from WD.
  3. edcoche thread starter macrumors regular


    Nov 2, 2007
    Im not sure you understood/fully read my post but yes I am aware that plastic does not conduct electricity. What I do know is that I have very dry hands and in the fall/winter when I touch my Blackbook occasionally it shocks it but does not cause it to shut down or anything. I can just feel and hear it. This happened while backing up my computer earlier and it abruptly stopped the initial Time Machine backup.

    The WD external drive still functions fine and it showed no symptoms of there being anything wrong with it. A that point I simply wanted to start the backup from scratch and reformatted the external drive and started over and it finished successfully.

    Just wondered if the shock might have damaged the external HD in any way my computer is fine as it always is whenever that happens. I think the shock just caused the WD to eject thus putting an end to the backup that was going on. Thats my theory anyway.
  4. Prodo123 macrumors 68020


    Nov 18, 2010
    If you're aware of the fact that plastic does not conduct electricity, how would static electricity damage the hard drive or the internals inside of a plastic casing?
  5. edcoche thread starter macrumors regular


    Nov 2, 2007
    I have a feeling you mainly are on this board to belittle people asking for honest advice. That or you don't understand what took place.

    I was simply remarking that I touched my computer while the initial Time Machine backup was underway, the static electricity shocked my computer, and at that precise moment the progress bar on the Time Machine backup stopped moving and about 5 seconds later the HD was ejected putting an end to the backup. Immediately there was a prompt on my screen saying that the device was not ejected properly just like it says if you pull it out of the usb port before its properly disconnected.

    How can we not be seeing eye to eye on this? It doesn't really matter anyway b/c you clearly aren't feeling very helpful by the way you are responding to my posts trying to make me sound like I'm some kind of idiot.
  6. Prodo123 macrumors 68020


    Nov 18, 2010
    Again, your BlackBook is in a plastic's practically impossible that an outside shock can damage internal components when
    1. Your computer is charging, since the charging cable is connected to a ground that absorbs static electricity
    2. A plastic casing creates a sealed environment where static cannot penetrate into and damage the hardware within.

    It's a faulty drive. It might still work, but it's a faulty drive and a hell of a coincidence.
  7. Lennyvalentin macrumors 65816


    Apr 25, 2011
    It's not that simple when dealing with such high voltages. The fact the external drive got ejected tells us something happened in that discharge.

    Anyhow, one should always make sure the computer and all its attached peripherals are grounded to the same ground, that means attaching the extension lead to a Macbook's charger before plugging it into a wall socket (since the detachable power plug does not transmit ground). That helps when dealing with static electricity.

    It's almost certainly not a faulty drive.

    Also, lose the smartass attitude. Thankyou.
  8. Prodo123 macrumors 68020


    Nov 18, 2010
    This will be the last time I'll say it: this is not static damage. Static electricity is quite simple as long a you are grounded.
    Static damage would do much more severe things to a computer than a mere ejection of a drive. More likely it would have caused your computer to freeze and crash.
    If you want to keep your ignorant attitude and forgo what I say here, I can guarantee that you will have a very unpleasant time with that drive.
  9. ZipZap macrumors 603

    Dec 14, 2007
    If these devices are connected by a wire, then its indeed possible for current to pass between the 2 devices.

    Edcoche, there is no way to assess damage other than a change in the functional state of the computer or the drive. Since both appear to be working, it was likely a hiccup.

    I suffer the same issue in the winter, and I always forget to discharge myself.

    Dam 100oz carpet.
  10. Prodo123 macrumors 68020


    Nov 18, 2010
    If 2 devices are connected by wire, then yes electricity can flow between them.
    When 2 devices are connected to a common ground such as your situation, static electricity does not flow through that wire but to the common ground.
    A common ground drains the static electricity from you without the need to discharge. That's why most people should wear electrostatic wristbands that attach to a ground wire, to avoid static damage.
    Now if you were backing up using battery power then it would make sense that the computer and hard drive was damaged by the discharge. Since you were using a stationary drive (and therefore is most probable that you were charging the computer too), there will be no static electricity inside the computer.
  11. edcoche, Oct 31, 2011
    Last edited: Oct 31, 2011

    edcoche thread starter macrumors regular


    Nov 2, 2007
    My MacBook and the WD external HD were connected to an extension cord. It is a 2 prong cord and it lacks the 3rd prong for ground, I think I'll be investing in a proper cord right away. The WD drive works fine, I was able to load time machine and it showed the backup and my MacBook works just fine too. At this point I'm thinking hiccup.

    Does anyone else have any thoughts on the condition of the external HD?
  12. heyloo macrumors 6502

    Nov 2, 2006
    I'd get the proper cord right away indeed.

    Also, yes, it's possible that the static may have conducted through your USB cable and may have caused the disconnection. Seeing that your hard drive is working fine again, I wonder if WD has a failsafe switch that caused the disconnect when it happened. If your drive is new, it wouldn't hurt to ask WD if they could exchange the HDD for you, or give you suggestions on how to check if everything is working fine. I guess the least that you could do is to use disk utilities to just make sure that your hard drive is 'okay'.
  13. ZipZap macrumors 603

    Dec 14, 2007
    You like to make assumptions to support your argument. No doubt that a properly grounded situation will not generally result in discharge damage but this is not 100%. Also, its clear the OP is describing something else.

    As you can see above the OP has stated he is not grounded.

    And in my direct experience, being properly grounded is not a guarantee that some sort of charge will not pass through. If you touch the computer near where the USB connector is attached static can easily follow that path of least resistance through the cord.

    In the end, the OP does realize that properly discharging and getting a grounded AC cord is necessary.
  14. CylonGlitch macrumors 68030


    Jul 7, 2009
    Sounds like the OP created what is called a ground bounce. What this is, is a change in the voltage level of the ground plane. Under normal conditions, the ground is at zero volts; but it is possible to cause it to jump up to a voltage level above zero. Normally it returns back to zero right away, and thus it's called a bounce.

    Since the USB interface uses a differential pair of signals that are referenced from +/- 5v if the ground plane changes, it could give bad reading and thus make the device look corrupted. When this happens, OSX immediately ejects the disk. I've caused this several times (I design USB devices). Windows handles it quite differently by shutting down the device; but essentially doing the same thing.

    The shock you gave the computer is not really an issue. The BlackBook is in a common ground cage and thus the shocks get mitigated by that. What I'm guessing happened is that this caused a voltage spike down the common ground (which for you doesn't go to earth ground), which is connected to the shielding of the USB cable and down to the hard drive. The hard drive, it seems, has tied it's common ground to the ground of the PCB (actually, a very common mistake) thus the spike hit the ground plane of the controller PCB. Which in turn, most likely reset the controller and confused the heck out of the laptop.

    I wouldn't think that you did much damage, although you MIGHT have shortened the life of the controller card on the hard drive. But since it appears to be working well, I would think not. Most modern IC's these days have spike protection built into them -- much harder to zap via static (I've tried).

    I wouldn't worry about it much; just try to avoid this in the future. I suggest before opening your laptop you touch a piece of properly grounded metal first. This will discharge any static.
  15. Prodo123 macrumors 68020


    Nov 18, 2010
    Not an assumption; I repair electronics and must deal with static quite often. If a properly grounded computer connected via USB conducts static electricity, then it's faulty wiring because the metal sleeve of the USB cable is a ground connection designed to shield the data cble from such discharges. This shielding is grounded on the host side, not the peripheral.
    Thus, if it was a ground bounce caused by the 2-prong connection, then it should have damaged the computer if it did any at all. Otherwise the only reason a the hard drive would do this is if it is a faulty drive.

    And yes, the moral of the lesson is to keep a proper ground at all times.
  16. edcoche thread starter macrumors regular


    Nov 2, 2007
    I just want to send out many thanks to those who provided insight on my concern. I ended up playing it safe and got a new HD to err on the side of caution.

Share This Page