three pronged plugs?

Discussion in 'Mac Pro' started by flat6, May 14, 2006.

  1. flat6 macrumors regular

    Oct 24, 2004
    I'm in the unfortunate position where the only power outlets available have two prongs, while my white power supply wire is a three-pronged version. I can make the two fit (they're both North American) but does doing so pose a risk to my computer? What is the purpose of that 3rd prong anyway?
  2. flat6 thread starter macrumors regular

    Oct 24, 2004
    'What happens if you cut off the ground prong or use a cheater plug so you can plug a three-prong appliance into a two-prong outlet? Nothing really -- the appliance will still operate. What you have done, however, is disable an important safety feature that protects you from electric shock if a wire comes loose.'

  3. PatrickF macrumors 6502

    Feb 16, 2006
    I'm not sure about the US plugs. In the UK, however, we get 2 plug adapters with our power bricks.

    One is the extended cord and the other is simply the plug that pops onto the brick. I assume that this is the same elsewhere. Now the extended cable does connect to the ground while the small plug does NOT connect to the ground plug on the brick.

    So I would say that if you're using the small plug and it's the same as the UK version then it wouldn't connect to the ground either way.
  4. skubish macrumors 68030


    Feb 2, 2005
    Ann Arbor, Michigan
    Its the same in the states. The extension is 3 prong but the adapter that attaches directly to the power brick is 2 prong. But that is with iBooks and PBs. The original poster didn't specify what computer they had. You will lose the ground if you use an adapter but I don't think it is a big deal.
  5. wordmunger macrumors 603


    Sep 3, 2003
    North Carolina
    If you have an adapter, you may be able to ground it yourself. Usually the adapters have a fitting where you can attach a wire. If your house has metal pipes, just connect a wire from the adapter to the nearest pipe. If you don't have metal pipes, then you'll have to run the wire all the way outside and into the ground, or at least to another ground wire somewhere in your house.
  6. ®îçhå®? macrumors 68000


    Mar 7, 2006
    If you are in the Uk, the three prongeed plug is there because the third prong is to ground it. In the Us, every single house/plug is grounded but in the UK, there is a station at the end of each road. By using a 2 pronged plug, it should not really be effected but is at a slightly higher risk of electricuting you
  7. mpw Guest

    Jun 18, 2004
    Is that right? I know the third prong top/centre is the ground but an awful lot of appliances don't use it the reason there's a third prong is that without it you wouldn't be able to use most sockets as the earth prong is longer and must engage with the socket before the live and neutral socket hole will open to accept the plug.
  8. howesey macrumors 6502a

    Dec 3, 2005
    They go to an earth spar outside your house, and also connect to water/gas pipes.

    Ground is more than just for protection, it also serves a lot of purposes to electronic design. For example, in audio.
  9. iMeowbot macrumors G3


    Aug 30, 2003
    Most US style adapters have a little prong that lines up with the wall plate screw. In most cases, if you slip that screw in, it will give you some grounding. Generally (generally), even the old two-wire boxes are grounded because they are attached to shielded cable, so attaching that tab will be a little bit better than nothing.
  10. PatrickF macrumors 6502

    Feb 16, 2006
    Even though all UK plugs have the earth prong, not all appliances use it as mpw points out. A lot of appliances are double insulated and thus don't require earthing.

    Also as mpw points out that all (good) UK sockets require that the earth prong (which is slightly longer than the live/neutral prongs) be inserted before the live and neutral can.
  11. jmsait19 macrumors 6502

    Jan 26, 2004
    so in short, go ahead and use an adapter to convert it, you will be fine.
  12. flat6 thread starter macrumors regular

    Oct 24, 2004

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