Most probably american or japanese, black is live, white is neutral and/or red is second live for 100-0-100 centre tap supply , green is earth. However, be very careful before plugging it in - it may well be expecting 100 or 110volts rather than the 230 or so we have here, in which case it will probably run very fast, but not run for many seconds before going bang, unless you have a transformer to step down the voltage!
Seriously if you are not sure you should look for a rating plate on the side, or makers contact info, and call them to determine the voltage.
Also, although it is nearly certain that green is the earth, if you have access to a meter you would be wide to check that the exposed case connects to this wire, and that there is high resistance between the other two and the case.
The thicker wire is also a probable indicator of a low voltage high current country, rather than the the EU and Australasia that use higher voltage and less current for the same power
(Though the cord could have been replaced at some time so almost anything could be true - for example here in the UK I came across some old east german flex a few months ago, black live, grey neutral, red earth, fortunately before I made the red one live I checked it, but it could have been very nasty indeed had I assumed the old UK red is live rule).
