Today, I had a new PC screen at home, but without power adapter. I got the one from the old screen and I had to replace the original plug for another one, that matches with the new screen. The one problem I have is the color code. The power adapter has two output wires: one black and one white, and the other cable (the correct plug) has three wires: browm, yellow/green and blue.

The problem is: I don't know wich wire is the correct one (+/-), not sure if black is + and blue is + too or these are the other wires.

I would like to know what respresents each color code in this case (black, white, green/yellow, blue).

I can't attach any photo of it because the phone's camera is broken, so I'm adding a little "description":

From power adapter: - Black - White

From the new plug for the screen: - Green/yellow (both) - Blue - Brown


  • Is it just IEC C13/14? If so, and you don't have a particular need to hardwire it, you're probably better off just buying a premade cable. – Bob Feb 16 '17 at 23:50
  • Seriously the mains are dangerous. If you have to ask then you don't know what you're doing. What do you mean by "adapter" anyway? People seem to assume you mean a cable that connects to your wall socket. Is that correct? – user1890202 Feb 17 '17 at 0:57
up vote 2 down vote accepted

The yellow/green is earth. It is required for safety but not for powering up the display.

If there are no metal parts exposed (and some other requirements) this wire might not be required.

The orientation of the other two wires does not really matter for getting things to work. The live wires are brown = black and the neutrals are blue = white.

  • 1
    So, if I understood correctly, then, I have to connect the brown one and the white together and the blue and black so it can work, true? – spund3 Feb 16 '17 at 20:30
  • @user1831847 NO! Black is HOT, white is Neutral. White should be connected to blue, black should be connected to brown. – DerStrom8 Feb 16 '17 at 20:42
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    @DerStrom8 Fixed. (seems that is also why US and Canada drives on the wrong side of the road.) – skvery Feb 16 '17 at 21:03
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    Oh hell, so may I have burned the device :/ – spund3 Feb 16 '17 at 21:14
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    @user1831847 nor smoke nor anything that proves that it has been burned. So the device shall work correctly (when it's not). Thanks anyways :) – spund3 Feb 16 '17 at 21:27

In the UK:

The green/yellow wire is the earth cable - it is for safety and should generally be used if its there - but isn't required.

The brown is the live wire - you can remember this by it being the colour your trousers turn if you touch it.

The blue is the neutral wire.

Here is a page on the wire colours and their meanings for different parts of the world: Wiring Colour Codes

Probably it's as follow:

  • Black: phase
  • White: neutral

On the other case:

  • Green/yellow: earth
  • Blue: neutral (usually very close to earth in monophase systems)
  • Brown: phase

Don't you have a polarity tester so you can check it?

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