Video: Making a Proper Terminal Connection


Electrical systems and water don’t mix, and sooner or later every boater faces issues caused by salt, moisture and vibration. Fortunately, you can reduce the likelihood of such problems, or at least prolong them, by making sure your terminal connections are properly made, crimped and sealed.

It all starts with the right components, which include marine-grade, tinned-copper wire. Marine-grade wire is specifically designed withstand the harsh conditions, including exposure to salt, sunlight and petroleum products. Also, it’s important to use the proper gauge wire or cable for the job (based on wire run and amperage), and to use marine-grade terminals with adhesive-lined, heat-shrink tubing, which ensures a watertight seal.

The proper tools also make wiring jobs easier and eliminate future problems. I recommend purchasing an automatic wire-stripping tool, like the kind made by Ancor. This tool strips off the proper amount of insulation with a simple squeeze of the trigger.

Another useful tool is a ratcheting crimper. This tool applies firm, even pressure around the connector sleeve, ensuring a perfect, secure crimp and without damaging the wire or heat-shrink tubing. Lastly, make sure you have a sharp pair of cutters, so that the end of the wire butts up squarely against the base of the terminal.


  • Step 1: Remove approximately 1/4” of the wire insulation, or jacket.
  • Step 2: Insert the exposed end of the wire into the terminal sleeve until it butts against the end of the terminal.
  • Step 3: Align the jaws of the crimper around the middle of the sleeve and firmly squeeze to form the crimp. If using a non-ratcheting crimper, be careful not to squeeze to much, which can damage the heat-shrink tubing.
  • Step 4: Test the crimp by tugging on the wire to make sure it doesn’t slip.
  • Step 5: Apply heat to the heat-shrink tubing. While you can use a butane torch or even a lighter for this job, a heat gun is easier to control and makes a better connection. Turn the wire in your fingers to ensure that even heat is applied to all sides or the tubing. Keep heating until the adhesive begins to bubble out the ends of the tube.