Electrical Cable Connector Types

Contents:

• What are electrical connectors
• Electrical connector types explained
• Key takeaways
• FAQs

Electrical connectors are a very important part of any electrical circuit, joining terminations to complete the circuit with a secure and reliable connection.

Choosing the right connector is crucial to the success of any electrical connection. The correct connector will create a secure and robust connection, it will be easy to fit and it will be able to withstand the environment it operates in. The right connector will also be correctly sized and designed for the task it will be used for, so it can be fitted safely and in line with the 18th Edition of the Wiring Regulations. 

In this guide, we will explain what the common types of electrical cable connectors are so it’s easier for you to find the right connector for your electrical circuits. We will cover power connectors, data and signal connectors, automotive and industrial connectors, computer and PCB connectors as well as some other important electrical connector types.

Most electrical connectors should be fitted by an electrician. If you need to hire an electrician to fit electrical connectors, you should always hire a competent and suitably qualified electrician, preferably registered with the NICEIC.

Electrical connectors join terminations in an electrical circuit to create a complete circuit.

In most cases, they are used to connect wires or cables to each other or to static points in a circuit. Connectors that connect cables and wires can be referred to as electrical cable connectors. However, electrical connectors are not only used with wires and cables.

The connector forms a connection so that power, data or signal can be transmitted through the circuit through electricity.

Typical places to find connectors are:

• At a fuse box

• At a switch, power outlet or lighting fixture

• As part of a computer or electronic device

• In automotive, industrial or medical equipment

The connection formed by an electrical connector has the potential to be a weak point in a circuit. Connectors need to be built to create a secure and reliable connection. They also need to be durable and designed to withstand the environment in which they will operate.

Connectors also need to be the correct type and fit for the circuit and conductors they join. This is crucial to both functionality and safety. Furthermore, connectors should also be easy to fit so that electricians can work efficiently.

In this section, we’ll explain what the common types of electrical connectors are, how they function and what purposes they serve.

 

Power connectors

Power connectors are the simplest type of electrical connector. They are used to create an electrical power connection in a circuit. Power connectors can be used to complete, extend or ground a circuit.

Power connectors come in a range of sizes, for everything from low to high voltage circuits. They are also designed for a variety of operating environments and to fit different types of conductor. As well as this, they can be designed to create either just one connection or multiple. A three way connector, for example, will connect three wires together into a single electrical path.  

Common types are:

• Crimp connectors

• Twist-on connectors

• Push-in connectors

• Terminal blocks

 

Lever Connectors

Lever connectors are simple and convenient connectors used to connect wires and cables in fixed wiring. 

Making a connection with a lever connector is fast and easy. You simply pull open the lever on the connector, insert a wire into the connection port and then close the lever. In some connectors, you don’t even need to open the lever before you insert the wire. You only use the lever if you need to disconnect the wire. 

Lever connectors are reusable. Some types also feature integrated testing points and transparent covers for visual inspection. 

Some uses for lever connectors are: 

• Domestic circuits (lights, switches, sockets)

• Appliances

• Industrial circuits

 

Crimp connectors

Crimp connectors are a widely used electrical connector type, used to join cables in fixed wiring.

Crimp connectors work by inserting wires into a metal connector and then compressing the connector around the wires with a crimping tool. The compression creates a secure mechanical and electrical bond that can withstand vibration and other stresses the connection will experience in use.

With crimp connectors, you need to choose the correct size crimp connector for the size of the wires being joined. You also need to match the crimping tool to the size of the crimp connector.

Common uses for crimp connectors are:

• Domestic wiring

• Automotive

• Aerospace

• Electrical appliances

The main benefits of crimp connectors are that they are durable, low cost and easy to use.

 

Push-in connectors

Push-in electrical cable connectors are a popular choice for modern electricians in the UK for domestic wiring.

Push-in connectors are used to join electrical wires together in a circuit. To create a connection between two wires, you strip the ends of both wires and insert them into the connector’s openings. Once inserted, an automatic mechanism grips the wires, securing them in place and creating an electrical connection.

You need to choose the right size push-in connector for the wires you’re joining.

Common uses for push-in electrical cable connectors are:

• Domestic wiring

• Lighting systems

• Commercial and industrial building wiring

The main benefit of these types of electrical connectors is their ease of use.

 

Terminal blocks and strips

Terminal blocks and strips are insulated blocks of connectors that are used to join two or more wires together in a circuit. Normally, they’re used for multiple wires.  

Terminal blocks have a plastic insulating frame and multiple terminals into which wires are fed and secured in place. The terminals also create a connection between all the wires and a central metal conducting strip.

A terminal strip is a linear unit with a collection of individual connections that are insulated from one another. They are used when multiple connections need to be well organised in a single location. 

The correct size terminal block must be chosen for the circuit in question.

Common uses for terminal blocks and strips are:

• Control panels

• Junction boxes and distribution boards

• Industrial machinery

• Automotive

The benefit of terminal blocks and strips is that they provide a safe, well organised single point of connection for multiple wires in a circuit.  

 

Junction boxes for cable connectors

Power connectors are often housed in junction boxes. These are opening and closing containers that protect and secure electrical connections. They protect connections from the elements and stop people from tampering or accidentally coming into contact with them. They also secure wires and connections in place to give the whole circuit more strength. 

You can find many types of junction boxes, for everything from light duty, single connections in internal electrics to weatherproof outdoor junction boxes that house multiple connections. Junction boxes can be made from plastic or metal, and they also come with different mounting options and internal layouts for connection housing.  

Other power connectors

Specialist electrical connector types are available for more specialist power applications, such as for high-voltage circuits or outdoor use. These operate in various ways but are designed to be used with particular circuits or in particular conditions.  

Some examples are:

• Cable connectors for permanent submersion

• Heavy duty 10mm² outdoor cable connectors

• Plug and socket power connectors

These connectors are designed and tested for particular operating conditions.

 

Data and signal connectors

Data and signal connectors are a type of electrical connector that provide an electrical connection for transmitting data and electrical signals. Some connectors, such as USB cables, also provide a power connection alongside this function.

Data connectors

Data connectors are interfaces used to transmit data through cables and between devices. As well as transmitting data, many data connectors also transmit power. Data connectors are commonplace nowadays, and most people are familiar with various types.

Here are some well known data connectors:  

• USB cables

• Lightning and micro USB cables

• Ethernet cables

• HDMI cables

Data connectors are specially designed connectors that need to be chosen for the task in question.

Audio, video and RF connectors

Audio, video and RF connectors connect cables and devices that transmit or receive sound and/or visual signals. These connectors come in a wide range of types with designs modified according to the signal being sent and the device receiving it.

Here are some common examples:

• Audio connectors 

• RCA connectors

• SCART leads

• Radio frequency (RF) connectors

The correct connector must be chosen for the task and device in question. High quality cables and connectors are often important for preventing signal loss and achieving a high-quality connection. 

 

Automotive and industrial connectors

There are various electrical connector types that are specifically designed for particular automotive and industrial applications.

Automotive connectors

Specialist automotive electrical cable connectors are designed to operate in the particular conditions they experience in use. This can include vibration, exposure to water and extreme changes in temperature. They are also designed to allow for easy assembly in manufacturing and easy disassembly for repair.

Some examples of automotive connectors are:

• Waterproof power connectors

• Automotive data and diagnostics connectors

• In-car power outlets

Industrial connectors

Other specialist connectors are designed for use with industrial machinery and equipment.

As with automotive electrical cable connectors, industrial connectors may be designed to operate in particular conditions. They may need to operate in extreme temperatures, be able to withstand vibration or need to be particularly durable. They may also need to provide unique functionality.  

Here are some examples of specialist industrial connectors:

• M12 and M8 connectors

• DIN 43650 connectors

• Circular MIL-spec connectors

Computer and PCB Connectors

Computer and PCB connectors are specialist electrical connectors that are used to make electrical connections in computers and other electronic devices. These connectors transmit power, data and other signals between devices and from power sources.

 

D-Shaped connectors

D-shaped connectors are a type of electrical cable connector that feature an external, D-shaped frame with multiple pins housed inside the frame. They are designed to provide a secure connection and to ensure the pins cannot be incorrectly aligned.

The security of D-shaped connectors means they’re commonly used on peripheral devices that are attached to computers. Many feature screw or latch mechanisms to ensure they cannot become unattached.

Common uses for D-shaped connectors are:

• Audio and video equipment

• Computer accessories

• Telecommunications

D-shaped connectors are also found in applications outside of computing, such as in industrial machinery.

 

PCB connectors

Printed circuit board (PCB) connectors are electrical connectors that connect components or devices to a printed circuit board. They are mounted directly to the circuit board. They also come in various sizes and configurations to support different component or device connections.

PCB connectors are composed of a housing that insulates the connection, ensures it is correctly aligned and mechanically secures it. Contacts within the connector complete the connection. PCB connectors may also come with locking mechanisms, seals or other types of security, depending on the environment they’re used in.

There are two main types of PCB connector:

• Through-hole mounted connectors - the leads of the connector are inserted into pre-drilled holes on the PCB

• Surface-mounted connectors – the leads of the connector are attached to the surface of the PCB

 

Plug and socket connectors

Plug and socket connectors are often used in computers and printed circuit boards, being used for both power and data connections. 

Plug and socket connectors are popular because they provide a secure, compact and well organised connection. They also create a reliable connection that efficiently transfers power and electrical signals without any loss. On top of this, having standardised connection types makes it easier to design and manufacture modular computer and PCB components. An internal computer cooling fan, for example, can easily be replaced if it is connected to a PC with a standardised plug and socket. 

Here are some common uses: 

• Main power connections 

• Data connections between storage devices and motherboards

• Power connections between devices and ancillary components

• Data and power connections between PCBs

 

Other types of electrical cable connector

Circular connectors

Circular connectors are electrical cable connectors that feature a circular connecting mount with internal metal pins. They can be used to provide a power connection or to provide data and signal transmission as well.

These connectors are designed for use in tough environments or to provide a secure connection in normal environments. They are also designed to be easily and quickly connected and disconnected by inexperienced personnel.

Common uses for circular connectors are:

• Aerospace

• Telecommunications

• Industrial

• Medical

The main benefits of circular connectors are their mechanical stability and easy connecting and disconnecting. They also support good contact integrity and can be shaped to prevent incorrect alignment.  

Rectangular connectors

Rectangular connectors feature a rectangular connecting mount with internal metal connecting pins. They can be used to provide a power connection or to provide data and signal transmission as well. They serve a similar function to circular connectors, but they allow for more efficient use of space and for higher pin density in the connection.

These connectors are designed to provide a secure connection and can be used in tough environments. Untrained personnel can also easily connect and disconnect them, although not as quickly and easily as circular connectors. Rectangular connectors excel in applications with limited space because they can be placed closely together with minimal wasted space.

Here are some common uses for rectangular connectors:

• Industrial

• Medical

• Telecommunications

• Consumer electronics

Lighting connectors

Lighting connectors are designed to deliver power to lighting and components in lighting circuits. They can deliver power to lights as well as to fixtures, switches or control systems. Electricians often simply use the same connectors used in other fixed electrical circuits, such as lever or push-in connectors, for lighting. 

There are, however, some more specialist lighting electrical connector types. Some examples are:

• Blade connectors used in automotive lighting

• Waterproof connectors used for outdoor lighting

• Circular connectors used for stage lighting

Lighting connectors should conform to any standards and regulations that apply to them. Most importantly, they should conform to the 18th Edition of the UK Wiring Regulations. Key factors affecting the safety of lighting connectors are their load capacity, durability and fire resistance.

Electrical cable connectors come in a wide range of types and sizes for a wide range of uses. All electrical circuits, from high-voltage power circuits to the circuits in small electronic devices need connections at various points. These connections are a potential weak point. However, using high quality, correctly chosen connectors will reduce or eliminate the risk of a fault arising.  

The different types of electrical cable connector are all designed for specific uses and environments. It’s very important that the correct size and type connector is used in any application. If you use the wrong connector, it could result in an unreliable or dangerous connection.  

Looking to expand on your knowledge of electrics? Find out more about domestic electrics, including the top signs that a circuit needs replacing, in our guide to rewiring a house.