How to fix broken wires the easy way – with heat-shrink butt connectors

How to fix broken wires the easy way - with heat-shrink butt connectors

Home & Office
Why you can trust ZDNET : ZDNET independently tests and researches products to bring you our best recommendations and advice. When you buy through our links, we may earn a commission. Our process

‘ZDNET Recommends’: What exactly does it mean?

ZDNET’s recommendations are based on many hours of testing, research, and comparison shopping. We gather data from the best available sources, including vendor and retailer listings as well as other relevant and independent reviews sites. And we pore over customer reviews to find out what matters to real people who already own and use the products and services we’re assessing.

When you click through from our site to a retailer and buy a product or service, we may earn affiliate commissions. This helps support our work, but does not affect what we cover or how, and it does not affect the price you pay. Neither ZDNET nor the author are compensated for these independent reviews. Indeed, we follow strict guidelines that ensure our editorial content is never influenced by advertisers.

ZDNET’s editorial team writes on behalf of you, our reader. Our goal is to deliver the most accurate information and the most knowledgeable advice possible in order to help you make smarter buying decisions on tech gear and a wide array of products and services. Our editors thoroughly review and fact-check every article to ensure that our content meets the highest standards. If we have made an error or published misleading information, we will correct or clarify the article. If you see inaccuracies in our content, please report the mistake via this form.

Close

How to fix broken wires the easy way – with heat-shrink butt connectors

No soldering skills required.
A heat-shrink butt connector -- perfect for joining wires together!

A heat-shrink butt connector — perfect for joining wires together!

Adrian Kingsley-Hughes/ZDNET

My how-to post on soldering yielded some feedback from readers asking for my opinion of heat-shrink butt connectors.

Yeah, I know. I’ve been using these for years and the name still makes me chuckle. Sadly, my kit calls them “solder sleeve connectors” but they’re the same thing.

Also: This tiny USB-C tester can spot counterfeit Apple chargers

So, what are heat-shrink butt connectors? When should (and shouldn’t) you use them? And how do you use them properly?

Kuject 350PCS Self-Solder Heat Shrink Butt Connector

ZDNET RECOMMENDS

Kuject 350PCS Self-Solder Heat Shrink Butt Connector

Solderless, crimpless, butt connectors. All you need is just a heat gun to create a solid, weatherproof joint.

View at Amazon

Heat-shrink butt connectors (yeah, I’m still giggling) are sleeves of heat-shrink tubing with a ring of solder in the middle and two rings of adhesive at each end.

You apply heat, and the solder melts to join the wires together and the glue softens to create a weatherproof seal. 

Also: How to solder: Tools, tips, and tricks to get you started the easy way

So, when should you use a heat-shrink butt connector?

  • When you need to make a strong and reliable electrical connection between two wires.
  • When you need to protect the connection from moisture, corrosion, or other environmental factors.
  • When you don’t have access to a soldering iron or don’t have the skills to solder the wires together.
  • When you want to avoid the use of crimp connectors that may work their way loose over time.

Here’s when not to use a heat-shrink butt connector:

  • When the wires are too large to fit into the connector.
  • When the wires have different gauges (thicknesses) and the connector isn’t suitable for the smaller wire.
  • When the wires are exposed to high temperatures that may melt the connector.
  • When the wires will be exposed to high-vibration environments, which can cause the connector to loosen over time.

As for voltages, I’ve seen these connectors rated to 600 volts. However, I would never use them for anything more than 12/24V automotive or marine applications.

Also: This is the perfect mini electric screwdriver

For AC power, I’d use a Wago connector (these are rated to 32A/450V), but I always recommend getting professional advice when dealing with power lines.

How to use a heat-shrink solder butt connector 

1. Prepare the wires

Strip 1/4 inch of insulation from the ends of the wires that you want to connect. If possible, twist the exposed wire strands together to create a tight connection. (This might not be possible with some wire.)

2. Select the appropriate connector for the wire.

These connectors come in a variety of sizes. Follow the guidance on the packaging as to which size to use (and put the lid back on the box when you’ve chosen one so you’re not playing pick-up off the floor with the rest of the butt connectors).

3. Insert the wires into the connector.

Slide the connector over one of the wires, making sure the wire is inserted all the way into the connector. Repeat this step with the other wire.

4. Align the connector.

Position the connector so the exposed wire ends are touching each other.

5. Apply heat.

Use a heat gun or a lighter to heat the entire connector until the solder inside melts and flows around the wire strands. Make sure to apply heat evenly to all sides of the connector to ensure a good connection.

6. Allow to cool.

Once the solder has flowed around the wires, allow the connector to cool completely before handling it. The solder will harden as it cools, creating a secure and permanent connection.

7. Inspect the connection.

Check the connection to ensure that the wires are securely connected and that the tubing is tightly sealed around the connection.

Wires aligned and ready for the heat to shrink the connector.

Wires aligned and ready for the heat to shrink the connector.

Adrian Kingsley-Hughes/ZDNET

Personally, I’m not a fan of using naked flames to shrink the butt connector, because, well, things can burst into flames.

Fire!

Adrian Kingsley-Hughes/ZDNET

I find using a hot air gun from a rework station to be safer and less dramatic.

Shrinking a butt connector with a hot air gun.

Adrian Kingsley-Hughes/ZDNET

A perfect joint! 

A perfect joint!

A perfect joint! 

Adrian Kingsley-Hughes/ZDNET

I like to finish with a bit of adhesive-lined heat-shrink over the entire repair, giving it extra stability and weatherproofing. 

Also: This has replaced my multitool for a fraction of the cost

Remember, if you’re going to do this you need to fit the heat-shrink onto the wire you’re joining before joining them together with the butt connector.

I like to finish with a bit of heat-shrink over the entire repair.

I like to finish with a bit of heat-shrink over the entire repair.

Adrian Kingsley-Hughes/ZDNET

That’s a repair to be proud of!

Editorial standards

Add a Comment