How to Wire a 12 Volt Inline Fuse

Updated April 17, 2017

"Inline" is a characteristic of the fuse holder and how to use a fuse, not a characteristic of the fuse. Inline fuses protect the electrical device and provide accessibility and environmental protection for the fuse. An inline fuse implies that it is fusing the target electrical device and nothing else. Inline fuse holders include wires on each end for connecting to the power source and the electrical device. Access to the fuse is often provided through a twist-lock cap. Manufacturers make different types of inline fuse holders for unique applications. As an example, clear plastic fuse holders allow an inspection of the fuse.

Cut the power-source wire from the electrical device to be fused. Use the wire-strip-and-crimp tool to strip the insulation, allowing approximately 3/8-inch of bare wire. Inspect the stripped wire to ensure that none of the copper strands were cut. Twist the copper wire, to form a tight end with no loose wires. Strip the other end of the power-source wire the same way.

Strip both ends of the inline fuse-holder wires using the same technique. Insert one end of the stripped power-source wire into the wire crimp. Using the wire-crimp tool, secure the wire to the crimp. Ensure that the crimp is over the bare wire and not the insulation. Attach one end of the inline fuse holder to the other end of the crimp. Using the wire-crimp tool, crimp this wire the same way. Repeat this process to connect the other end of the inline fuse holder to the remaining end of the power source.

Test the connections with a gentle tug and inspect to ensure there is no bare wire exposed. Check the 12-volt fuse to make sure the amperage is sufficient to protect the electrical device. Remember that the voltage of the fuse is not critical as long as it is higher than the battery. The amperage of the fuse is what provides the protection. Insert the 12-volt fuse into the fuse holder and apply power to the unit. Check to see that the fuse does not blow.


A good wire-stripping-and-crimping tool can save you hours of rework.

Things You'll Need

  • Inline fuse holder (with wires)
  • 12-volt fuse
  • Wire-strip-and-crimp tool
  • Crimps
Cite this Article A tool to create a citation to reference this article Cite this Article

About the Author