Like the other posters, the use of speaker wire had me a little alarmed as these macerators can draw 20 amps or more. Twenty amps requires 12 gauge wire. For safety's sake, I installed a 30 amp fuse on 10 gauge wire to the macerator I had in my boat. I never had any problems and it worked just fine. Maybe my installation was a bit over capacity, but it made me feel safe.
Using a wire that is too small can cause the wire to get hot and burn the insulation, and/or cause the voltage to drop which could damage the motor to the macerator.