Do I fuse

[mr steve wayne]

I just purchased a boat with a Motor Guide Trolling X3 motor. I do not know if the X3 has a built in fuse some place, and I see no fuse holder on the batteries. Should I add one? And if so what kind and size?
The same is true for my Lawrence Elate 5 depth finder.
Do I need to fuse on both? And what would you recommend?
Thanks, Mr. Steve

[shrew]

The device dictates the draw. The draw dictates the wiring size. Fuses and breakers protect the wiring.

Look at how much the device draws. Make sure the wiring is sized for the draw, voltage, and distance. Then size the fuses accordingly. The fuses should be as close to the battery as possible.

If you're running from the Fuse bus (recommended), then I would place a large fuse directly on the positive terminal of the battery to protect the wiring from the battery to the panel, this will need to take to total load. I would then size the fuses from the panel to device accordingly.