C2 End Cap Connector

Overview

Twist-on 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 insert, which threads onto the wires and holds them securely. When such a connector is twisted onto the stripped ends of wires, the wires are drawn into the connector's metal insert and squeezed together inside it. Electrical continuity is maintained by both the direct twisted wire-to-wire contact and by contact with the metal insert.

Installation

Twist-on wire connectors are typically installed by hand. They may have external grooves to make them easier to handle and apply. Winglike extensions are commonly molded into higher quality connectors to reduce operator muscle fatigue when installing a large number of the connectors. Such extensions also allow these connectors to be installed with a common nut driver or a specialized tool.

Color Coding

Twist-on wire connectors are commonly color-coded to indicate the connector size and, hence, their capacity. They are commonly 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.

Limitations

Twist-on connectors are 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.

Specialized Versions

Ceramic Twist-on Connectors: Made for high-temperature applications, such as heating appliances.

Gel-filled Connectors: Designed for wet environments, such as outdoor or underground use.

Aluminum Wire Use: Generally not recommended; however, some manufacturers offer rated versions. The US Consumer Product Safety Commission only approves specialized crimp or screw terminal connectors.

Feedthrough Connectors: Feature a hole in the top for pushing a bare wire through to form a pigtail for grounding. These are typically green and also called "screw-on grounding connectors".