How to Choose the Right Wire Connectors

Select the correct wire connector type when splicing wires

Wire Connectors

Wire connectors are UL Listed fasteners used to make a tight low impedance connection between two or more electrical wires in an electrical box. Made of flame-retardant materials, wire connectors prevent wires from contacting other wires or exposed metal surfaces, which could cause a dangerous fault or short circuit. 

This guide will explain the different types of wire connectors, so you can feel confident you’re choosing the right connectors for your project.

How Do Wire Connectors Work


Wire connectors are available in a variety of sizes and shapes. While their exterior covering is typically made from insulating plastic, their means of connection is a tapered coiled metal spring or interior grooves that thread onto the wires and holds them securely. 

When a connector is twisted onto the stripped and twisted-together ends of wires, the wires are drawn into the connector's metal spring and squeezed together inside it. Electrical continuity is maintained by both the direct twisted wire-to-wire contact and by contact with the metal spring or insert.

Twist-On Wire Connectors

twist-on wire connectors


Twist-on wire connectors are typically installed by hand. They may have external grooves to make them easier to handle and apply. Wing-like extensions are commonly molded into higher quality connectors to make attachment easier. Such extensions also allow these connectors to be installed with a common nut driver or a specialized tool. 

Twist-on wire connectors are:

  • Commonly color-coded to indicate the connector size/capacity. 
  • Frequently used as an alternative to terminal blocks or the soldering of conductors together, since they are quicker to install and, unlike soldered connections, allow easy subsequent removal for future modifications. 
  • Not often used on wire gauges thicker than AWG #10 (5.26 mm²), because such solid wires are too stiff to be reliably connected with this method. Instead, set screw connectors, clamps or crimp connectors are used. 
  • Typically used in electrical wiring systems for light switches, receptacles, ceiling fans, can lights, thermostat controls, HVAC, smoke/CO detectors, garage doors, door bells, security systems, recessed lighting, signage and more.

Wire Connector Types


Wire connectors come in seven main designs, each tailored to a specific purpose.

  • Twist-On Wire Connectors
  • • Don’t require pre-twisting wires, but recommended
    • Make fast, easy to use, secure electrical connections
    • Can be removed easily and in most cases re-used
Twist-on Wire Connector
  • Winged Twist-On Wire Connectors
  • • Don’t require pre-twisting wires, but recommended
    • Wings speed up the attachment process
    • Ideal for large projects requiring multiple connectors
    • Make fast, easy to use, secure electrical connections
    • Can be removed easily and in most cases re-used
Winged Connector
  • Twist-On Grounding Wire Connectors
  • • Look the same as winged twist-on
    • Designed for making ground connections and bonding non-metallic sheathed cable
    • Can be removed easily and in most cases re-used
Twist-on Grounding Wire
  • Crimp-On Wire Connectors
  • • Designed for making fast, permanent, pressure-type connections
    • Make fast, easy to use, secure electrical connections
    • Copper or steel construction
    • Not reusable
    • Requires a crimping tool
    • Plastic cap insulators can be used after connection is made
Crimp-on Wire Connector
  • Underground Wire Connectors
  • • Protects against moisture and corrosion
    • Ideal for buried wire
    • Typically filled with 100% silicone sealant.
    • Easy to apply, pre-filled twist-on wire connector
    • Usually used for buried electrical cables in sprinkler systems and similar applications
    • Generally not reusable
Underground Wire Connectors
  • Waterproof Wire Connectors
  • • Protects against moisture and corrosion
    • Typically filled with 100% silicone sealant.
    • Easy to apply, pre-filled twist-on wire connector
    • Usually used for low voltage outdoor lighting systems and similar applications
    • Eliminates the need for heat-shrink or excessive taping
    • Generally not reusable
Waterproof Wire Connectors
  • Push-In Wire Connectors
  • • Alternative to twisting wires together
    • No twist push-in design reduces repetitive motion fatigue
    • Has the wires pushed into connector for fast and easy connections
    • Clear shell gives visual verification of connection
    • Compact size typically takes up less space in electrical box
    • Can be removed by pulling and twisting on conductors
    • Generally can be re-used
Push-in Wire Connector


Tip: Some electricians prefer crimp-on wire connectors for joining ground conductors in an electrical box.