Grounding question

Discussion in 'General Electronics Chat' started by rufusrufus, Jun 6, 2014.

  1. rufusrufus

    Thread Starter New Member

    Jun 6, 2014
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    Hello everyone,

    I don't understand electricity all that well and thought this would be a good place to double check something.

    If I'm using a laptop that is plugged in through power (it is 3 pronged so I believe it is grounded) on a table sitting on a concrete slab in my house whilst sitting barefoot on the grass in my back yard - is this perfectly safe? and if there is any sort of electrical fault with the device am I still safe? ie I don't become the ground?

    And what if I had the laptop plugged in through power resting on a table in the backyard on the grass along with myself barefoot. Would this still be fine too?

    It's a Toshiba laptop. The power brick has AC/DC on it. 3 Pronged to the power outlet.

    Sorry if these questions seem ridiculous/silly. I just want to double check to make sure I'm not putting myself in any harm's way. As I said before I don't really understand electricity so sorry for these questions...

    Thanks!
     
  2. Treeman

    Member

    May 22, 2014
    158
    15
    I have a Toshiba. I never take it into the bath with me when the 3 prong is connected.
    I too know very little about electricity but on the basis that millions do what you do everyday with no problem I am comfortable assuming it is safe.
    As a last resort try playing AC/DC (1970's) on your headphones when plugged in. This may equalize any potential difference including with the neighbours.
     
  3. studiot

    AAC Fanatic!

    Nov 9, 2007
    5,005
    513
    Your laptop itself will always be safe.

    The issue is whether the power supply brick has a fault that could make metal parts on the laptop live. If the supply brick is in good order then it too will be safe in the conditions you describe.

    If there is any doubt you can take both to a competent electrician or electrical stor and have them tested under the PAT regulations.
    PAT stand for portable appliance testing and covers anything that may be plugged into and unplugged from the mains as distinct from apparatus that is permanently wired in.
     
  4. rufusrufus

    Thread Starter New Member

    Jun 6, 2014
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    What if I was using a usb keyboard and mouse and not touching the laptop at all. Would that further increase my safety factor? or can it just as easily affect you if there was a fault?

    EDIT: The Laptop is only a few years old as well. Never had any issues with power so far.
     
  5. studiot

    AAC Fanatic!

    Nov 9, 2007
    5,005
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    Keyboards and mice are plastic and therefore insulated.

    The only danger is if the power brick becomes faulty and allows the mains to connect directly to the metal outer of the power lead.
    If that happens then metalwork on the laptop could conceivable become live and you could get a shock via the metal usb outer when plugging in a keyboard.

    But this is a very remote possibility and there are several electrical safety barriers for the fault to overcome before this could happen and Toshiba is a particularly reputable manufacturer here.

    Are you experiencing problems? It is much more likely that these would be due to static electricity.
     
  6. samuel.whiskers

    Member

    Mar 17, 2014
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    I suspect more people get hit by lightning than get electrocuted from their laptop computer.... relax mate....
     
  7. rufusrufus

    Thread Starter New Member

    Jun 6, 2014
    4
    0
    Not experiencing any problems. I just wanted to make sure I'm not putting myself at any extra danger by using the laptop plugged in while directly grounded barefoot to the earth.

    From what I understand, my body is not grounded in the house and most people would use their laptop plugged in inside the house or would use battery mode only when going outside. So I just wanted to make sure that it is perfectly safe for me to be earthed while using a laptop through mains which is also earthed through the 3 prong plug. That is the only reason I am asking :) otherwise I'm perfectly fine using the laptop like I normally do.
     
  8. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    7,388
    1,605
    Is there some reason you ask this? Did you ever feel any shocks?

    You should be quite safe doing this. When a house is wired for electricity the "ground" that is referred to is often literally an 8 foot copper rod driven into the very same ground you are sitting barefot on. Hence your feet are (literally!) at ground potential, so there is little to fear from using a grounded appliance.

    In the old days things came in metal boxes and that box was also connected to ground, just in case something came loose you are not left holding a high voltage in your hand. Lately this have moved to double insulated, meaning the wires have insulation and that is enclosed inside a non-conductive case. That means two things have to fail before you can get shocked.

    I don't know your specific laptop but if it has a metal case that case is grounded; that is the same as done on my desktop PC. This basically guarantees your laptop and your feet have no voltage to give you a shock.


    I don't always listen to AC/DC, but when I do, so do my neighbors.
     
  9. rufusrufus

    Thread Starter New Member

    Jun 6, 2014
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    Lol.

    This is my laptop:

    http://homenetworking01.info/2011/1...e-l750-laptop-computer-part-no-psk2ya-04p028/

    The case looks like plastic, but probably has metal inside the case?
     
  10. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,545
    2,370
    It is rare these days to find a laptop with a 3 pin plug, all mine have 2 pin with isolated switching supplies, so naturally the DC common is not at earth ground potential as it is on a Desktop PC where the low DC common side is connected to earth ground.
    Test the continuity between the USB common and the power plug earth pin.
    Max.
     
  11. wmodavis

    Well-Known Member

    Oct 23, 2010
    737
    150
    If you drive a car, ride a bicycle, ingest high levels of sugar or walk barefooted in the grass you are in way more life threatening danger than the extremely remote possibility of shock from your setup. And from experience shocks aren't that bad to deal with - many of us have survived that and much more.
     
  12. Treeman

    Member

    May 22, 2014
    158
    15
    I don't always listen to AC/DC, but when I do, so do my neighbors.[/QUOTE]

    :D No neighbours here. Detached bungalow. Try UFO live in Germany 1970 before the NWOBHM disaster. A hidden gem.
     
  13. inwo

    Well-Known Member

    Nov 7, 2013
    2,433
    315
    I would never intentionally contact anything, line connected (or most anything else) while bare feet are in contact with earth.

    I'm sure it's a perfectly safe design, and verified by someone.

    You don't know what you don't know, but hey, that's just me.:D
     
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