yeah. definitely keep the ballasts seperate.
it will keep the heat down a bit more in the canopy, and its a hell of a lot safer.
sometimes the green wire is supposed to be used as the ground wire...
like when you wire it to an extension cord, the green wire is always used as the ground, and is connected to the bottom prong on a 3 prong plug.
i saw a ballast wiring faq somewhere, ill try and find it for ya
http://members.fortunecity.com/paulerik/id51.htm
*another bit from another site*
Wires/ Wiring
Wires used in electrical circuits are often of two types, stranded or solid, and are rated by size, current capacity and temperature handling capability of the outer plastic sheath. Stranded wire is flexible, and much more resistant to breaking.
The wire size is indicated by the gauge of wire. It describes diameter (smaller the gauge the thicker the wire) and is directly related to the maximum current that the wire can handle. For our purposes, and for lengths under 25’, we can run a lamp up to 1000W on 18 gauge wires. This takes into consideration a line voltage of 120VAC and a moderate safety factor.
The outer insulating jacket of a cable is rated for a specific voltage. Most insulation is rated up to 600 volts, which is fine for our purposes. The outer jacket is also rated with a letter designation. S denotes a high quality, 2-conductor cable with an outer jacket of high-quality rubber. SO or SJO denotes the same, with an oil-resistant jacket of neoprene or similar material. In the environment we use our lighting, these are a good choice. If using single-conductor cable, THWN refers to a water-resistant thermoplastic insulator, and is the best choice.
When wiring ballasts remotely from the lamps, it is often convenient to use a connector of some sort so that the two components can be disconnected. A simple solution is the use of normal household extension cords, cut in two, with one end wired to the ballast, and the other to the lamps. The female connector should be connected to the ballast, and the male to the lamp, so that an energized plug could not come into contact with your hand. Other good connectors such as Hubbell twist-lock style connectors provide a locked connection, and are different from most household connectors.
The wiring diagrams for connecting the ballast to the lamp are usually printed on the ballast cover. Always use a three-pronged plug for connecting the ballast to the outlet, and make sure the wires are properly grounded. Most circuits require that the outer case of the ballast be grounded.
When working with electricity, please exercise caution and seek the advice of a qualified electrician if you are unsure of what you are doing.