I bought a new monitor and it comes with a thick power plug but I noticed there's a ground wire dangling but sheathed with hard clear plastic but basically it looks like the image below:

enter image description here

What is the purpose of the ground wire? How should I use it? do I plug the wire in the grounding hole of the socket?

  • 2
    In Canada something like that would be illegal. Used to be screwed on to screw holding outlet faceplate or an adapter. Should be replaced with proper cord with three prong plug. Was made illegal because most people would not use it and most times was a poor grounding connection.
    – crip659
    Mar 5 at 15:40
  • Here they're still legal (as far as I know) because the alternative (folks yanking ground prongs out of their cords) is not ideal.
    – isherwood
    Mar 5 at 15:58
  • @isherwood sounds like a badly designed plug to me .... should use one more like the UK plug where even if you rip the cord out the plug, the earth is always the last to disconnect!
    – UKMonkey
    Mar 6 at 20:26
  • 1
    @UKMonkey Here we go again... you literally can't show a picture of an electrical plug anywhere without a Brit popping up to offer prayers for the BS 1363, lol. Power strips the size of a lorry and munted feet from treading on those monsters... I don't miss them one bit. ;P
    – J...
    Mar 6 at 22:41
  • @J... They put lego to shame when it comes to feet killing - that's for sure!
    – UKMonkey
    Mar 8 at 14:04

That cord is meant to plug into a Japanese outlet. In Japan, it's common to have two-prong sockets with a separate grounding screw below for devices that need it.

The outlet it was desinged to plug into looks something like this:

Japanese outlet

To use your monitor in the US, simply replace that cord with a standard US computer monitor cord, an IEC C13 - NEMA 5. They're very inexpensive.

  • 1
    "Inexpensive" is right. I work at a computer service place, and we have so many of the things cluttering up our office that we'll just give you one if you stop by and ask nice. Mar 6 at 15:51

That type of wire, along with the tab on 3:2 "cheater plug" adapters, is intended to go under the face plate screw at the center of the outlet. That screw makes a connection with the outlet chassis, to which its grounding screw connects. Of course, this assumes that the outlet itself is grounded via wire or metal conduit.

enter image description here


Monitor cords are a dime a dozen. They're provided with a great many electrical appliances and folks tend to have extras laying around. If you prefer, swap that one out for a three-prong version.

  • is it safe to keep it dangling like that? it does have a kind of a plastic cap. not sure if I should tape it or not. Indeed 3 prong ones would be better.
    – Bahamut
    Mar 5 at 16:55
  • Can also just cut that plug off and replace with proper three prong plug.
    – crip659
    Mar 5 at 17:25
  • As cheap as proper 3-prong cords are, @crip659, it would be about the same to just buy a replacement cord and not have another hack job on site. (This plug contrivance being the first hack job.)
    – FreeMan
    Mar 5 at 17:26
  • 1
    No danger in it dangling other than the ungrounded state of your equipment. Taping it doesn't make sense.
    – isherwood
    Mar 5 at 17:27
  • 1
    @crip659 if it is that cord it would be incredibly easy to find pretty much anywhere in the world. It’s an IEC C13 cord. bestbuy.com/site/searchpage.jsp?id=pcat17071&st=iec+cable
    – Tim
    Mar 6 at 10:45

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