We have just received our solar panel but it seems that the cable was not part of the shipment. My understanding was that it came with 16 feet of the necessary cabling?
Unfortunately there is no such thing as a "one size fits all" wire for solar panels. The distance between the panel and your batteries combined with the wattage of the panel are the criteria for selecting a wire. Since the distance between a solar panel and batteries vary, there is no way for a manufacturer to know and in turn provide the right wire. This is very similar to a battery, alternator, wind generator, battery charger, etc… all these items do NOT come with wires because there is too much variability in each installation. It is up to your installer to decide on the right wire for your setup.