Also a very good idea to give it a little protection by putting it into some split loom and tape closed every foot or so which will help stop the wire from accidentally coming out of the loom. Also if it were me, I would order enough new wire to make the run all the way from the battery to the helm without splicing in. Two reasons, if you make the splice and it is under the boat you run a higher risk of developing oxidation/resistance at your splice point. Which over time can reduce the power throughput of the wire, which can limit effectiveness and also create heat. Second reason is you also run the risk of your splice somehow down the road coming loose and having to redo it. I know there are a lot of good ways to splice that SHOULD never give a problem, but easier to just spend the extra $40 and do it right the first time. Now if your splice is going to be only 3ft and therefore above deck and either under helm or in the battery compartment, a little different. You still can have the corrosion issue, but shouldn't be as prone to the problem as under deck and in the water. Remember, your ground is just as, if not more, important as your power. I would look for fully tinned 100% virgin copper. But that's just me. Sonic electronix usually has some decent cheaper stuff.