I want to fix Christmas lights like these, whose wires got cut near the batteries. The LEDs near the batteries still work.

I tried touching the wires from the two parts and I was surprised that the they seem to have metallic insulation. I sliced one LED at the end and confirmed that touching the inner rods does turn this LED on. Here is a picture of the two pairs of wires I want to solder:

Two pairs of wires to solder

The outside of the wires has a silver color, the inner rod looks like copper.

What is the name of this type of insulated wire, and how to solder it back together?

  • \$\begingroup\$ a detailed picture of the wire you want to repair may help us... \$\endgroup\$
    – Solar Mike
    Dec 3, 2018 at 15:33
  • 2
    \$\begingroup\$ if its rubbery ,cut it off, if its a hard coating, some sand paper might do the trick. \$\endgroup\$
    – Tim M
    Dec 3, 2018 at 15:42
  • 3
    \$\begingroup\$ Probably it's just an insulated copper wire covered in varnish. You could try sandpaper or something indeed. These are a bit painful to solder well. \$\endgroup\$
    – Lundin
    Dec 3, 2018 at 15:52

2 Answers 2


Enameled wire. Has a thin, strong lacquer coating as insulation. This can be colored as you have there. You simply scrape it off with a blade or sand paper, or burn it off with a lighter. Once the wire is exposed, tin and solder like normal.

  • \$\begingroup\$ Sounds right. I will try sanding or burning it. \$\endgroup\$ Dec 3, 2018 at 15:56
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    \$\begingroup\$ I find using a lighter can be a very painful way to go (burned fingers, melted insulation). Instead use your soldering iron, put a big blob of solder on the end and drag the wire through the solder blob. This works well for me for stripping smaller gauge magnet wire. \$\endgroup\$
    – Jim
    Dec 3, 2018 at 20:23
  • \$\begingroup\$ @Jim melted insulation is the point. Not that it melts, enamel and lacquer burn off nicely. \$\endgroup\$
    – Passerby
    Dec 3, 2018 at 20:25
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    \$\begingroup\$ Burning off with a lighter was the easiest option and the first I tried, so I am accepting this answer. \$\endgroup\$ Dec 6, 2018 at 10:16

It's a copper wire coated with lacquer (it's called lacquered copper wire), which gives insulation and water resistance (based on the required color for LED string).

You can see all these Christmas light strings will come in multiple colors.

Enameled wire is mostly used in magnetic applications like motors, transformers etc... so it is usually called magnet wire.

You can just remove that layer with knife, fire or by using heat from soldering iron... do tinning to both joints and solder.


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