How to fix a broken wire

If you run across a broken wire in the midst of a project, don’t fret. Depending on what materials and how much space you have to work with, you have several options. Here’s how to fix a broken wire.

The key to fixing a broken wire is to restore the connection, which means splicing the wire back together mechanically and electrically and insulating the joint. You can use connectors if you have room, or solder the wire if space is tight.

Safety first

Always disconnect the power when you’re working on wiring. Even with low voltage wiring, you don’t want the device powering up while you’re working on it. With household wiring, the danger is twofold. You don’t want the device powering up and you don’t want to shock yourself either.

Wire insulation

If the problem is just the insulation, and the metal wire is intact, here are some tips for fixing wire insulation.

The easiest way to fix a broken wire: Use a connector

The easiest way to fix a broken wire, by far, is to use a connector. There are several types of connectors available for making these types of repairs. The first thing to do is strip back a bit of insulation to give yourself some room to work with. I like to give myself somewhere between a quarter inch and a half inch.

 

The type of connector you use depends on the application.

Any method involving a connector works best when the wire won’t be subjected to much stress.

Splicing wire with wire nuts

If you have some physical space to work with and enough slack in your wire, wire nuts are the easiest solution. After stripping the wire, twist the bare ends together by holding the bare ends with one hand and twisting with the other. Use pliers if the wire is thick.

 

how to fix a broken wire
Twist the stripped ends together. Go vertical, don’t try to twist it parallel to the wire. The wire nut needs a vertical connection to thread onto.

Then place a wire nut on the end, cinch it down just like a nut on a bolt, and then cover the end with a couple of turns of electrical tape. As long as the joint won’t be subjected to mechanical stress, this is a good solution electrically, and good from an ease of use standpoint.

how to fix a broken wire
After you twist a wire nut onto the wires and secure it with some tape, you’ll have a reasonably durable repair, and it’s very quick and easy.

The major caveat here is to use the right size nut. If the wire doesn’t fit, use a bigger nut. If the fit is too loose, use a smaller one. For two wires, I find it best to stick with the gray, blue, or orange ones, depending on the thickness of the wire. Gray is best for small wires, while orange is usually adequate for heavy ones.

Splicing wire with a butt splice connector

If you don’t have enough slack for a wire nut, you can use a butt splice connector. With this type of connector, you butt two bare ends of the wire together and crimp it down, forming a good electrical connection and an acceptable mechanical connection. Ideally you should use a crimping tool for the best strength. Using pliers will usually give an acceptable electrical connection but the mechanical connection will be questionable.

Splicing wire with lever connectors

You can also use a lever connector to splice wire. With these connectors, you open a lever, insert bare wire into a hole, then close the lever. This type of connection beats all others from an ease of use standpoint. The downside is that lever connectors are expensive, and the connection isn’t super strong mechanically.

Fix a broken wire with soldering

The best way to fix a broken wire is to solder it. It provides the best all-around connection both mechanically and electrically, and when done right, the repair is stronger than the original.

For a really professional fix, slide a piece of heat shrink tube just slightly larger than the insulation over the wire. Use a piece slightly larger than the area of the repair. Twist the wire ends together, perpendicular to the wire, then apply a bit of flux. Flux helps the solder to flow and stick better.

how to fix a broken wire
You can twist the wires parallel to the rest of the wire, but it’s easier to get a good connection if you do it this way.

Heat up the soldering iron, then heat up the wire and apply a bit of solder to the wire, not to the iron.

how to fix a broken wire
I couldn’t catch the iron on the wire at the same time as my solder because I was trying to solder with one hand and take a picture with the other. Apply the iron to the wire to heat it up, then apply solder to the wire, not the iron.

The solder will flow evenly and give a nice, shiny connection. Spray a bit of alcohol or contact cleaner onto the joint to clean away the flux.

how to fix a broken wire
A good solder joint will be shiny. A dull solder joint indicates the solder didn’t make a good electrical connection.

Fold the splice down onto the wire, then slide the shrink tube over the splice to cover it completely.

how to fix a broken wire
Shrink tube gives a more professional look and a longer-lasting repair than tape.

Apply some heat from a hair dryer or heat gun to shrink the tube down. This results in a strong, professional looking fix.

how to fix a broken wire
A soldered connection with heat shrink is like a broken bone, the repaired section will be stronger than the rest of the wire.

If you don’t have enough slack to do the repair this way, simply cut a bit of wire and splice it in using the same technique, just doing it twice. This lengthens the wire, giving you enough room to perform the repair. Use the same gauge of wire, or one slightly larger. Try to avoid using a significantly smaller wire, to avoid voltage drop or overheating.

A repair carried out this way will look professional, because this is how professionals splice or fix a broken wire when they encounter one.

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