Yes never wire directly to the battery a recipe for a disaster at sea !!! I recommend what rockfish said use a 30 amp fuse and 10 gauge wire you should be good to go...
I use wire on all my riggers I buy it online or at Trotac,I won't use scotty wire I buy 7 strand wire it was recommended from my freind Malcom Russel,if you know that name then you might have your boat set up like mine.He a voltage electrolysis expert !!!! In the commercial boat circle they call him the doctor.His father invented the black box,Malcom has made a better model for scotty with a pulse mode so it can drag the current of the boat down to .200 and releases it it climbs back up slowly to .800 or if your boats really hot then .900 of one volt.
If you go to my name and do a search I think I made a post about the whole system its pretty unreal set up and does make a difference !!!!
Tight lines
Billydoo