I am trying to replace and rewire the streetlight display I have.....The wires I have is kinda too thin.....the orignal wire that was for the wall outlet to the display was waaaay too small, it was AWG 18/3 wire......too small....I was searching for a good size wire, found a nice wire, but its European and I need help knowing the coding of the wire and what it is equivalent  to....anyone can help?

I'm not sure if I can help...what is the coding on the wire?

Usually european (well UK as I know) have something like: "3x0.75mm2" which means that there is 3 cores, usually live, neutral and earth, and the 0.75mm2 means the conductor is 0.75mm2. For lighting etc, I use at least 1mm2.

You also get 3G0.75mm2 which is just the same as the above. 

If it is single cores, then the size will be embossed onto the sheath of each core, either 1.0mm (5A rating) 1.5mm (10A) or 2.5mm (20A). If a cable then the outer sheath has the embossed code. You will find in a cord there are 3 or more inner conductors. If 2 core then only for a double insulated item ( no earth/ ground wire).

Colours are simple, Green/yellow is earth( in US ground), red or brown is line ( US hot) and black or blue is neutral( USA common). If multicore there may be additional cores of white, yellow, or numbered black cores. If there are 7 cores, with a white that is thicker, then that is an automotive trailer cable, and is not rated for connection to the mains, voltage rating is 60V only.

Similar recommended wire sizes would be:      1.63mm = 14 AWG
                                                                        2.05mm = 12 AWG