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As a homeowner, it’s a matter of time before you’ll need to learn some basic electrical skills as part of your home improvement projects. You might need to splice wires to extend a wire, repair damage, or connect one electrical wire to another. 

Splicing wire is a technique for joining two pieces of wire together to carry an electrical current. You do this for many projects, like relocating light switches or outlets and making repairs. 

Read on as we cover the ins and outs of how to splice electrical wires safely for your DIY projects. 

Safety Considerations

Whether it’s your first wiring project or your 100th, safety is critical. Be sure to follow the tips below to ensure you’re staying safe. 

Always disconnect power to the circuit at the service panel before you begin working. Ensure the power is off using a non-contact voltage tester on the hot wires and ground wires before you get started. 

When you splice wire, always make sure you’re using the same gauge. When splicing wires of different gauges, the lower gauge wiring can handle more amperage than the higher gauge wire. As the current travels through the splice, it can overheat and create a fire risk.

When splicing wires, always use a junction box to place all the spliced wires.  Junction boxes protect from electrocution and fires by containing any sparks that occur during a short circuit. Attach the junction box to a wall stud or ceiling joist in a spot that won’t place undue stress on the wiring. 

Be sure to finish all your connections with a shrink tube or a twist-on connector. Never use electrical tape to shield your connections.

How to Splice Electrical Wires

Follow this step-by-step guide, and you’ll be well on your way to splicing wires like a seasoned professional. 

Before Splicing 

Close-up of an electrician stripping the insulation off a wire.

Be sure to cut off power to the wires you’re splicing. Never splice wires if you’re unable to cut off the power. 

If you’re splicing insulated wires, use a wire stripper to remove about five inches of the outer sheathing from the wire. Then, remove about ½” of the plastic sheathing from the individual copper wires. 

Examine the wiring for signs of damage. Look for burnt wire insulation, cut wires, nicks, or bite marks. Remove any damaged areas before you begin splicing. 

Slide a piece of shrink tubing over the wire you’re splicing as you’ll need it once you complete the splice. You can skip this step if you’re using a wire cap to attach the wires. 

If you haven’t set up your junction box yet, use your needle-nose pliers to attach clamps into the openings on the opposite ends of the box. 

Making a Lineman’s Splice

Electricians started using the lineman’s splice, or Western Union splice, in the early 1900s. It’s ideal for joining two wires that will be kept under tension. Here’s how: 

  • Hold the wires parallel to one another. Bend the top wire down and over the bottom wire, and vice versa. 
  • Wrap each wire around the other wire several times until you run out of wire. 
  • Solder the connection to provide additional protection and conductivity. 

Using a Twist-On Connector

Close-up of an electrician putting a connector on a copper wire.

A twist-on connector is an alternative to the lineman’s splice. Here’s what you’ll need to do to complete this splice. 

  • Hold both pieces of wire even with each other.
  • Place both ends into the twist-on connector.
  • Twist the connector to lock the two wires into place.
  • Tug at each wire to make sure that the connection is strong.

When working with these devices, only use UL-listed products. Ensure that the connector covers all the exposed wiring you’ve stripped back. If you can see exposed wiring, you’ve stripped off too much. Trim your twisted wires and reconnect. 

After Splicing

A man using a screwdriver in an electrical junction box

After making your connections, place them in the junction box and put the protective cover on. Then, secure it with screws.

When to Call an Electrician 

While handling minor electrical repairs and modifications yourself is possible, the work can be dangerous if you’re not careful. If you’re feeling uneasy about doing electrical work yourself, call in a professional electrician. 

With over 30 years of experience, our team at U.S. Electric can get your job done safely and efficiently. This way, you can enjoy your home or business to the fullest. Contact us today to discuss options with a professional electrician!