The question is what’s the best way to label the wiring on your boat. The photo above shows one person’s take on this, use a sharpie and write on the wire insulation to tell you what the cable is for. Certainly this is something I see fairly often on new boats right from the factory and the bottom line is that it actually meets the ABYC E-11 standard. But, I would suggest that this may not be the best approach to take. One, its pretty hard to write clearly on a piece of 14 AWG wire in a legible fashion, two, if the wire ever gets re-terminated, part of the description will probably end up going missing; as you can see in the above photo the writing is right next to the crimp connector on many of the wires shown. My personal preference on new boats are printed heat shrink labels. These get purchased in sheets and are actually run through an old DOT matrix printer. As long as they don’t get shrunk into place too close to the terminal, re-termination will not impact the label. I’ve seem paper labels used and they simply don’t hold up. 3-m does make some paper labels that get sealed with a transparent plastic overlay once you write what you what on the label. Again, as long as the label isn’t too close to the end, all is well. Pre-printed numbers on heat shrink tubes are also a good choice. Just make sure to provide a decoder chart that tells what wire # 23 is for. You get the idea. Just remember, ABYC E-11 offers broad latitude for identifying the function of DC conductors. For AC wiring, it’s best to strictly follow the internationally accepted colors, black or red for “hot” wires, white for neutral and green or green with a yellow stripe for grounding or “earthing” conductors.