I am needing to run a dedicated power cord extension for my humminbird 597ci HD DI unit from the bow of my boat to the battery in the stern.  Will any wire work for the extension since the 6' cord power cord they give you is not nearly long enough or will I need to buy some special wire.  I know the one they provide you is insulated, but don't know where you can buy that.  Will probably be about an extra 12 foot run.  Thanks for the help.

You can use any stranded wire as long as it is 16 guage or larger.

 

Solder and waterproof the splices. Put a 3A spade type fuse/holder at the battery on the positive wire.

A waterproof fuse holder is wise. You can get those at Radio Shack.

 

I prefer to use marine grade tinned conductors.

What Wayne said, but my personal preference is 12 gauge.  I just prefer the additional protection against voltage drop, but I know it's overkill.

You can use any stranded wire as long as it is 16 gage or larger.

 

Solder and waterproof the splices. Put a 3A spade type fuse/holder at the battery on the positive wire.

A waterproof fuse holder is wise. You can get those at Radio Shack.

 

I prefer to use marine grade tinned conductors.

X2, You want all splices soldered, and all connections both air & water tight; liquid tape works very well.  The fuse & holder is a must.  IMHO, Do not run the new power wires next to the trolling motor wires which are usually on the port side of the boat, you can pick up interference each time the TM is started & stopped.  If possible keep as much distance from other wiring as possible; some wires that drive motors (live well, bilge) and tachometer circuits are noise producers; you want to stay away from them.

What Wayne said, but my personal preference is 12 gauge.  I just prefer the additional protection against voltage drop, but I know it's overkill.

 

I use 12 guage also.

Thanks guys!!  That helps a lot!!  Will hit the Marine store after work today.  I have heard of guys just using extension cord wires to do this, but I think I am going to do it right and go ahead and go with marine grade wire.  Will also go with the 3A fuse/holder.  Thanks for all your help.