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A ring terminal, also known as a ring terminal connector or terminal lug, is a type of electrical connector used to terminate a wire to a stud, screw, or terminal. It consists of a hollow metal tube (or barrel) that is crimped onto the wire and a ring-shaped terminal that provides a secure connection point. Ring terminals are available in insulated and non-insulated varieties, offering versatility for different applications.

Functions of Ring Terminals

Ring terminals serve the primary function of providing a secure and reliable connection between a wire and a terminal point. The ring shape allows for easy attachment to screws or studs, while the crimped connection ensures a strong and durable bond with the wire. This design minimises resistance and enhances current flow, reducing the risk of loose connections that can lead to electrical failures or hazards.

Ring Terminal Insulation

Insulated Ring Terminals

Insulated ring terminals feature a layer of insulation, typically made of nylon or vinyl, that covers the metal barrel. Some of these covers are heat-shrunk onto the wires. The colour of each ring terminal covering denotes wire size, based on the following:

• Red: 0.5 mm² to 1.5 mm²
• Blue: 1.5 mm² to 2.5 mm²
• Yellow: 2.5 mm² to 6 mm²

This insulation provides protection against accidental contact with live conductors, making these ring terminals ideal for applications in which safety and electrical isolation are critical.

Non-insulated Ring Terminals

Uninsulated ring terminals do not have an insulating layer, exposing the metal barrel. These ring terminal connectors are designed for applications where insulation is unnecessary, allowing for higher current capacities and better heat dissipation. They can accommodate larger-stranded wires, studs, and bolts; however, more specialised tooling is often required for these heavy-duty terminals.

Ring Terminal Materials

Copper Ring Terminals

Copper ring terminals are widely used due to copper's excellent electrical conductivity and corrosion resistance. Due to their low resistance, they are particularly well-suited for high-current applications.

Brass Ring Terminals

Brass ring terminals offer a combination of good electrical conductivity and corrosion resistance, making them suitable for marine environments or applications with higher exposure to moisture or saltwater. Brass is also harder than copper, providing greater durability and resistance to wear and tear.

Stainless Steel Ring Terminals

Due to their excellent corrosion resistance, stainless steel ring terminals are well suited for harsh environments, such as when chemicals or corrosive substances are present. These ring cable lugs are often used in marine, chemical processing, and industrial applications.

Ring Terminals with Special Features

Flared Ring Terminals

With a flared or widened ring opening, flared ring terminals allow for easier insertion onto larger screws or studs. This flared design provides additional surface area for contact, enhancing the connection's strength and reliability.

Crimp-On Ring Terminals

Crimp-on ring terminals are attached to the wire using a crimping tool, which compresses the barrel onto the wire to create a secure connection. Using a ring terminal crimp ensures a strong and durable bond, preventing accidental detachment and ensuring efficient current flow.

Solder-On Ring Terminals

Solder-on ring terminals have a barrel that is soldered onto the wire, creating a permanent connection. Soldering is often preferred in applications where high vibration or mechanical stress is expected, as it provides a stronger bond than crimping.

Ring Terminal Applications

Automotive Industry

• Battery Terminals: Ring terminals are commonly used for wiring to battery terminals in automotive applications, providing a secure and reliable connection for the battery cables. They ensure efficient current transfer and prevent accidental disconnection.
• Starter Motor Connections: Ring terminals are used to connect the starter motor to the battery and the vehicle's electrical system, ensuring a strong and reliable connection for high-current starting circuits.
• Alternator Connections: Ring terminals are used to connect the alternator to the vehicle's electrical system, allowing for efficient charging of the battery and powering of various electrical components.
• Sensor and Actuator Connections: Ring terminals are used to connect various sensors and actuators in automotive systems, providing reliable connections to monitor and adjust factors such as oxygen levels, throttle positions, and temperature.

Energy Panels and Distributions Boards

• Circuit Breaker Connections: Ring terminals are often used to connect wires to circuit breakers in energy panels and distribution boards, providing a secure and organised connection point for circuit protection devices.
• Fuse Connections: In overcurrent protection devices, ring terminals can be found connecting wires to fuses in energy panels and distribution boards.
• Relay Connections: Ring terminals are used to connect wires to relays in energy panels and distribution boards. These provide a secure connection for control and switching applications, such as smart energy efficiency solutions.
• Grounding Connections: To ensure a safe and reliable path for fault currents to flow to the ground, ring terminals are essential for creating grounding connections in energy panels and distribution boards.

Industrial Applications

• Motor Control Centres: Ring terminals can be found in motor control centres, connecting motor cables to contactors, overload relays, and other control devices, providing secure and reliable connections for motor control circuits.
• Industrial Automation: Industrial automation systems widely use ring terminals to connect various sensors, actuators, and control devices, ensuring steady signal transmission and control for operational continuity.
• Power Distribution Panels: Ring terminals are used in power distribution panels to connect high-current cables to busbars, circuit breakers, and other components, ensuring efficient and safe power distribution.

Get Your Wire Ring Terminals from RS Singapore

RS Singapore has established itself as a trusted supplier and distributor of high-quality electrical components and devices, such as cable ring terminals. With our wide range of options sourced from leading brands like TE Connectivity, MECATRACTION, and Molex, we have something to meet every need.

RS Singapore also offers a comprehensive selection of other electronic components and mechanical hardware, such as coaxial cables and wire connector plugs, providing a one-stop shop for all your electrical and industrial needs. Our extensive inventory and user-friendly website make it convenient to browse and buy the components and equipment you need to complete your projects efficiently.

Receive your orders when and where you need them with our flexible delivery options. Visit our delivery information page to find out more about our delivery options, fees, and timings.