hey, i am a novice at all this, i don't know what the orange wire does im afraid, i used it because its the wire that the majority of people on here have used, there are a few threads on here in the forum section which are what i used to do it myself. From the threads on here it says you can use speaker wire, i wasn't comfortable using this wire so i went to my local motor factors and not knowing which grade of wire to use my self as i have no real electrical knowledge i just looked through their collection of wires and picked one that appeared the same thickness as the orange one its self. The sticker on the reel says 5amp 9/0.3mm auto cable, i also queried the cable with a friend, we both agreed that it is better than speaker cable. I've had mine wired in for about 6 weeks now and havn't experienced any problems.
Sorry i can't be that much help,
cheers