HomeTips & GuidesPigtail Wires: How To Make Electrical Pigtail Wire Connections

Pigtail Wires: How To Make Electrical Pigtail Wire Connections

Whether you are a DIY or professional electrician, you will almost certainly use pigtail wires at some point in your project. 

This short-length wire creates something like a last mile (or last inch) connectivity to create continuity to the endpoint. 

And you only need a scrap wire to make this connection. 

Let’s look at how to make pigtail wire links below.

Table of Contents

What Is a Pigtail Wire?

A pigtail wire is a short cable used to lengthen short wires. Also, it can join several wires to become a single conductor for electrical connections. 

This pigtail technique is applicable in several home and automotive wiring projects, especially for circuit grounding wires.

The National Electrical Code (NEC) requires a pigtail to be at least six inches long. Although this standard applies to house wiring, we can use the same for vehicle wiring.

Cars have an average of 274 pigtail connectors used to replace damaged connectors due to collisions, wear, or other issues.

An electrician handling three twist-on wire connectors

An electrician handling three twist-on wire connectors

Vehicle Electrical Pigtail Categories

Car pigtails fall into these four categories.

  • Power pigtail connectors: Link the head unit to the power supply, antenna, volume controls, switches, etc. This category also covers the short wires for joining power connections to electric windows, ignition systems, relays, and lights.
  • Speaker pigtail wire: Connects the vehicle speakers
  • Surplus pigtail connectors: Link specialty peripheral electrical devices, like CD changers, external amplifiers, and wired remote controllers.
  • Optional pigtail connectors: Connects devices like SatNav systems.
A car SatNav system

A car SatNav system

Performance Requirements for Car Pigtail Wires

As vehicles become more advanced, automakers need high-performance pigtail wires that can handle the electric current and signal transmission requirements for the respective applications. 

For instance, some connections must have high-speed, high-frequency pigtail connectors.

So, you need to consider the following factors when picking pigtails for vehicle PCBs, charging connectors, and more.

  • Electric current rating (current carrying capacity)
  • Voltage rating
  • Wire size (gauge)
  • Configuration
  • Circuit density
  • Engagement force

How To Make a Pigtail Wire Connection

Knowing how to make an electric pigtail is essential for car wiring projects. 

You might encounter damaged wire sections or short wires that need extensions to create electrical continuity between the two points.

For this task, you’ll need the following tools.

  • Scrap wire
  • Pigtail wire connector (traditional wire nut or push-fit/closed-end crimp connector)
  • DC circuit tester
  • Wire cutter
  • Screwdriver
  • Wire stripper
  • A pair of needle-nose pliers
A pair of needle-nose pliers

A pair of needle-nose pliers

Before embarking on the project, ensure the scrap wire matches the electrical properties of the wire in the circuit. Most importantly, check the wire gauge.

Step 1: Cut the Circuit’s Power Supply

Although car electrical circuits operate at a relatively lower voltage than household AC systems, you should disconnect the power supply for safety. 

So once you spot the damaged individual wires in the harness, undo the positive and negative battery terminals.

Use the circuit tester to confirm the circuit has zero voltage.  

The bulb should not glow when you contact the tester’s probe with any naked wire or metal contact.

Step 2: Disconnect the Device

Disconnect the damaged wire(s) from the device or unplug the connector to free the component from the wiring. 

After that, isolate the short or damaged cables and note their colors.

A car head unit connector

A car head unit connector

Step 3: Prepare the Circuit Wires

If you have a damaged wire, cut this section using a wire cutter to leave the good part. 

Next, prepare this short wire by stripping it about half or three-quarters of an inch to expose the copper for connecting to the pigtail.

If using a nylon closed-end or pigtail connector, you don’t have to strip the wire. You only have to cut the wire to have a flush edge.

Step 4: Prepare the Pigtail Wire

Use the wire cutter to chop a pigtail from the scrap wire to match the length of the cut section or the distance from the short wire to its destination. 

Ensure you match this wire gauge to the one you are joining it to. And the colors should be the same, as well.

A pile of scrap multi-colored wire

A pile of scrap multi-colored wire

Although less crucial than wire gauges, color codes matter for future maintenance. Strip this wire on both ends to have space for connecting the other wire and the device. 

But remember not to strip one end if you plan to use a pigtail or nylon closed-end connector.

Step 5: Connect the Pigtail Wire to the Device

Connect the pigtail wire to the electrical outlet or end device by tightening it with a screw. But you have to loop the bare wire around the screw terminal first. 

Some of these connections require soldering or crimping, so apply the appropriate action.

Step 6: Connect the Pigtail Wire to the Circuit Wire

This connection is critical to the circuit. If using a wire nut, twist the circuit and pigtail wires clockwise using the pliers. 

When tight, screw the wire nut in the same clockwise direction down the wire loop to secure the joint.

Two stripped wires before connecting them using a wire nut to create a pigtail connection

Two stripped wires before connecting them using a wire nut to create a pigtail connection

The nut should cover the entire connection, leaving no copper wires exposed. Tug both cables to ensure the joint is firm.

However, nylon closed-end and pigtail connectors operate differently; you don’t have to strip the wires to join the cables.

Pigtail connectors feature metal tines that slice through the insulation and contact the metal when compressed. 

So you only have to insert the pigtail and circuit wire inside, then depress the cap using a pair of pliers to push the metal tines through.

These connectors also have a dielectric silicone sealant (sometimes grease) to insulate the joint, creating a watertight barrier that protects the copper from corrosion.

A wire crimping tool

A wire crimping tool

Nylon closed-end connectors are also crimpable. They feature a nylon outer shell and a tinned copper barrel inside. 

So, after inserting the wires in the barrel, crimp the area around the outer shell using wire crimpers. 

You can seal the connection using dual heat shrink tubing or adhesive. 

These connectors are ideal for applications that experience excessive vibrations.

Step 7: Fit the Device Back Into the Vehicle

Once you test the joints for mechanical strength and electrical properties, insert the device back into the vehicle. 

After that, reconnect the battery terminals to the terminal posts, then test the end device. 

You might have to turn the ignition to power some components, such as the head unit.

A well-done pigtail connection

A well-done pigtail connection

Wrap Up

This guide should be enough to take you through the pigtail wiring process if you have doubts about doing this DIY electrical work in your vehicle. 

And you can use the same steps to create pigtail connections in household wiring. But if you still need help, contact us for further guidance. We’ll be happy to help. Have a good one!

Hi I am Christa, sales manager of Cloom.

I have extensive expertise and experience in wiring harnesses and I believe I can help you.

And we have a very professional technical team who can clearly understand the customer’s needs and give professional suggestions and solutions after receiving the drawings.

If you also have wiring harness needs, please send me the drawing so that we can give you our quote and start our business.

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