How to Splice Wire

Wire is commonly used to connect parts of an electrical circuit that are not mounted on the same surface. The wire must extend from surface to surface, leaving it exposed to potential forms of abrasion or stress wear. If a wire becomes damaged, it does not necessarily need to be replaced. The circuit may be restored by making a splice. Use this article to learn how to splice wire.


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    Locate the damaged area of the wire. The metal conductor of the wire is covered with a plastic insulation coating that should appear smooth. A crack, kink or burn spot on the insulation will be visible at the site of the wire damage
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    Clear the damaged area. Use a standard wire stripping tool to cut the wire on either side of the damaged area.
    • Evaluate the spacing of the cuts. The cuts should be far enough from the damaged area so that the damaged wire is all removed, but as close to the damaged area as possible to avoid cutting away undamaged wire. If the cuts are too wide apart, the wire may not be long enough to make the required connection.
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    Discard the damaged area of the wire.
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    Remove insulation from the 2 newly created ends of the wires. Remove about 1 inch (2.5 cm) of insulation from each wire end.
    • Choose the appropriate wire stripping opening on a standard wire stripping tool. A standard wire stripping tool will have multiple stripping openings. The corresponding wire size to be stripped will be marked on the tool.
    • Choose an opening cutting for an unknown wire size. If you are not certain of the wire size, pick a cutting opening that will cut fully through the insulation. Ensure that the inner opening is big enough to allow the metal conductor inside the insulation to pass through the cutting operation without being damaged.
    • Pull the stripping tool down the wire. Affix the tool about 1 inch (2.5 cm) from the end of the wire. Hold the tool firmly shut while pulling it down the length of the wire.
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    Form the wires. If the wire is made up of many smaller strands twisted together, gently maneuver the strands so they are all laying to form a smooth cylinder. If the wire is a solid conductor wire, this will not be necessary.
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    Place heat shrink tubing. To use heat shrink tubing to insulate the splice, cut off a piece of tubing about twice as long as the area of the splice. Slide it on to the end of either of the wires. Push it up the wire out of the way of the splice so that it is not prematurely heated by the splicing operation.
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    Connect the wires by twisting. Carefully twist the wires so that they remain in line with the rest of the wires, rather than bending up at an angle at the twist joint. The twist joint should have the wires snaking around each other in a line that continues the line of the original wire.
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    Prime the soldering iron. Place a small amount of solder on the end of the tip of a heated soldering iron. It will become a viscous liquid.
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    Solder the wires. Gently press the primed tip of the soldering iron on the center of the twisted wires. The wires will heat enough to melt solder.
    • Apply solder slowly to the wires. Apply enough solder to evenly coat the exposed wire surfaces. Do not get so much solder on the wires that it becomes a mass or ball and prevents you from seeing the wires.
    • Set the solder joint. Remove the soldering iron from the wires. Keep the wires still until the solder re-solidifies. The solder will dull slightly in shine as this occurs. The solder should set within ten seconds.
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    Insulate the splice.
    • Set heat shrink tubing. If you used heat shrink tubing to insulate the splice, slide it down over the splice. Using a heat gun, heat the tubing so that it shrinks to fit snugly over the splice. Do not overheat it or the tubing will crack and char.
    • Wrap the splice in tape. If you did not use heat shrink tubing, cover the splice completely with a helical wrapping of electrical tape


  • Heat shrink tubing is very fragile if heated unevenly. Do not try to heat it with the tip of the soldering iron or with your cigarette lighter.


  • Do not twist the wires together by cross wrapping them, as you would a twist tie on bread packaging. This will cause a bulky joint that will not withstand the soldering process. It will also create jagged edges and points that will puncture the new insulation.
  • The tip and tube of a heated soldering iron are extremely hot. Instant burning of the skin will occur if these surfaces are touched. Keep the soldering iron firmly in a stand while it is heated or is cooling from recent use.

Things You'll Need

  • Wire stripping tool
  • Soldering iron
  • Solder
  • Electrical tape
  • Heat shrink tubing
  • Heat gun

Article Info

Categories: Cabling and Wiring Connection