I am in the process of rewiring and installing a new Aqua Signal series 25 mast/deck light combo. (Page 702 in West Marine) and the new light has only 1 wire out the back? Where is the ground? The old light on the mast had two wires connected. I can't imagine where this thing grounds as no metal on the light touches the mast. (Light is completely incased in plastic) I hope someone can help me with this as I do not want to get it all back together and the mast back up and no light! How do I wire this? Thanks in advance. Matt