I ran a separate power feed (positive and negative fused near the battery) through a wire run pipe (built in the 170, there is a pull string already in there, just add another string to pull it back for use again). I originally used 12 ga marine wire (tinned so copper doesn't corrode so fast) but noticed a voltage drop when using the VHF on high power. I rewired using 8 ga (perhaps too stout) and no more voltage drop.
Below is a link showing the fuse in the rear (near the battery) and the fuse block I installed in the center console.
Installing a fishfinder in the 170CC