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  1. #1
    Seasoned Member allblack's Avatar
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    Default 'tricity question

    Because it's nearly random Friday.

    So I'm Googling why some plugs have 2 pins and some 3, which I (kindof) get, which leads on to the response that appliances with 2 pins generally don't need as much electricity to need to be grounded, so any problems and you'll just get a 'minor' shock.

    Which is comforting.

    So, if a plug goes into a socket, doesn't it pull (or receive) the same amount of electricity regardless of the appliance, or does my desk fan (2 pin plug) pull less power from the socket than my Monitor (3 pins)?

    I just KNOW there's people on here that love this sort of sh stuff!

  2. #2

    Default Re: 'tricity question

    The amount of power (measured in amperes - usually abbreviated to amps) is dependent on the amount of power an appliance uses. The usual amount in your household wiring allows for 10 amps. So if there is a leak in the power and you receive a shock it will be at least that amount and is not dependent on the fact that it has an earth pin or not. You will receive enough to give you a very good shock which may or may not kill you.

    A very good idea of the amount of power used was shown to me when somebody showed me what happens when you short out a car battery. The screwdriver that he used glowed red hot with the amount of power flowing through it. That, he said, was a lot more power than that which flowed through your house wiring, and it was a very good example of the amount of power available in a 12v battery.

    But I do not know why some appliances only have two pins, but I notice that American plugs do not have an earth pin. Hopefully someone else can elucidate.
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  3. #3
    Computer Technician wainuitech's Avatar
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  4. #4
    Seasoned Member allblack's Avatar
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    Default Re: 'tricity question

    Doesn't answer why some appliances only have two pins.

    Is my desk fan manufacturer guilty of producing a dangerous appliance?

    I doubt it. That article explains why 3-pin plugs exist, but not 2-pin plugs.

  5. #5
    Junior Member ManUFan's Avatar
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  6. #6
    Seasoned Member allblack's Avatar
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    Default Re: 'tricity question

    You just copied the same link as Wainui ...

  7. #7
    amateur expert dugimodo's Avatar
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    Default Re: 'tricity question

    Some devices which are double insulated and/or made of plastic are allowed to use a 2 pin plug. If it has a metal body it has to be earthed so it has to have a 3 pin plug.
    In some appliances there is simply nothing to connect the earth to as it's purpose is to make the metal body safe so there'd be no point using the extra wire.

    Silly thing is earth and neutral are bonded anyway and are effectively the same connection.

    And as for the "amount of power story" it's a load of bollox, 240V is just as dangerous to you regardless of how much power the appliance uses. Grab onto 240V with no load connected and tell me how "minor" that shock feels (but really don't, kidding... you never know someone might take me seriously).
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  8. #8
    Senior Member 1101's Avatar
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    Default Re: 'tricity question

    Quote Originally Posted by allblack View Post
    You just copied the same link as Wainui ...
    Did you read it then

    sort of this.....
    2 pins. The appliance has to be double insulated, ie no external metal , so in theory you could never get zapped off the case
    3 pins. The metal case is connected to earth. So if the 'live' wire breaks & touches the case , it short circuits blowing the fuse & keeping you safe
    the 3rd pin is connected to earth (literally)

    Now we get into issues with voltage differences between earths , so if you plug in you electric ruler at one end of the room, & plug in your electric pencil in a socket at the other end of the room , and touch metal cases of both with your tongue, you can get zapped .
    Dont laugh, Ive seen guitarists get a bit of a zap in practice rooms when the guitar & the mic's amps are plugged into different power sockets .

    None of this helps when you touch a frayed power cable & get zapped . had that happen a few times.
    Or you get a 3pin power cable , made of chinesium, where they didnt bother to wire the earth to anything inside the sealed plug.
    Last edited by 1101; 18-12-2018 at 02:32 PM.

  9. #9
    Seasoned Member allblack's Avatar
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    Default Re: 'tricity question

    Quote Originally Posted by 1101 View Post
    Did you read it then
    Of course. That's how I knew.

    I didn't read that from it, but then I wasn't sure what I was looking for.

    So for every applinace with 2 pins, there's a double-insulation thing going on within the appliance, that an applicance with a 3-pin plug does not need?

    Is that it, or is that too simplistic?

  10. #10
    Senior Member piroska's Avatar
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    Default Re: 'tricity question

    Ex-pctek

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