12v DC 500ma transformer - separate into different wires

Hi
I am building a little project from one of the "electronic gadgets for the evil genius" books, and it says I need a 12v DC 500ma transformer, and there are 3 wires from the project, +12v, 0v and earth.

The problem is, the only transformers I can find have a small metallic connector on the end
**broken link removed**

Is there something else I can buy with 3 seperate wires, or can I convert one of those like the one I linked into the + - and earth connections?

Thanks

You might want to post the schematic. Often the enclosure is tied to earth ground as a safety measure. In the case of a wall adapter it would not be needed since the voltage at the little plug is only 12 volts.

I sorted it out, sorry for the post

It was an american schematic, and in my mind I didn't think about how that would transfer over to a UK plug