Connection Materials

Discover the Different Types of Connection Materials for a Robust Installation

The market offers a wide variety of connection materials, each with specific properties and application areas. Understanding these differences is essential for making well-informed choices.

Wire connectors guarantee quick and safe wire connections

Wire connectors, often called push-in connectors or quick connectors, are a modern and widely used solution for connecting electrical wires quickly and securely. They have largely replaced traditional wire nuts and terminal blocks in many applications, mainly due to their ease of use and the consistent quality of the connection. There are various types of connectors available, including variants suitable for both solid and stranded conductors.

• How wire connectors work: With a wire connector, you simply insert the stripped wire into an opening. An internal spring mechanism firmly clamps the wire, ensuring a durable and gas-tight contact. This minimizes the risk of loose connections and overheating.
• Releasable wire connectors provide flexibility: Some wire connectors, such as the popular WAGO 221 series, come with an orange lever. This allows you to easily open the connector to insert or release wires. This makes them ideal in situations where the connection may need to be adjusted in the future. Standard push-in connectors without a lever are typically intended for a one-time, permanent connection.
• Applications in and around the house: Wire connectors are highly suitable for connecting wires in junction boxes, central boxes, and for connecting switches and lighting. They provide a reliable solution for extending circuits as well as for making branches, for example, for extra sockets or lighting points.

The transparent housing of many connectors makes it easy to visually inspect the connection, allowing you to check whether the wire is inserted correctly and if the copper is making sufficient contact.

Terminal Blocks

Terminal blocks are the traditional connection method and consist of a plastic or ceramic housing with metal clamps that secure the wires using screws. Although well-known, they are nowadays less recommended for permanent installations, especially with solid core (VD) wire. However, they are still suitable for flexible wires, such as when connecting a lamp, provided you use a ferrule to prevent fraying. Multiple wires under one screw is not safe and should be avoided.

• How terminal blocks work: You strip the wire, insert it into the metal tube, and tighten a screw to clamp the wire. Each tube is designed for one or two wires.
• The necessity of ferrules: When connecting flexible wires (composed of several thin copper strands) in a terminal block, it is absolutely necessary to use a ferrule. Without this sleeve, the strands may fray under the screw, leading to poor contact, heat buildup, and even fire hazards. A ferrule bundles the strands into a solid unit.
• Terminal blocks require care: The quality of a connection with a terminal block depends greatly on the installer's skill. Over-tightening can damage the wire, while under-tightening leads to poor contact. Additionally, terminal blocks provide no strain relief, which means the weight of a connected device or lamp should not be directly supported by the terminal block.

Power Plugs Safely Connect Devices to the Mains

Power plugs form the visible part of the connection between an electrical appliance and the socket. They come in numerous variants depending on current strength, voltage, and the presence of grounding.

• Grounded plugs for extra safety: In the Netherlands, grounded plugs (type F, "Schuko") and sockets are the standard. The grounding pins on the sides of the plug ensure that the metal parts of an appliance are grounded. In the event of a fault, current is safely discharged, preventing electric shock.
• Perilex plugs for heavier applications: For high-powered appliances, such as electric cooktops or heavy-duty equipment, Perilex plugs and sockets are often used. These plugs have five pins and are designed for 2-phase or 3-phase connections, depending on the type of cooktop and installation.
• Installing a new plug: Correctly connecting a plug to a cable requires precision. The phase, neutral, and earth wires must be attached to the correct terminals, and the strain relief must be properly secured to prevent the cable from being pulled out under tension.

Ferrules are Essential for Stranded Wiring

As mentioned before, ferrules are crucial when using flexible electric wires in screw connections, such as terminal blocks or some types of terminal strips. They consist of a thin metal tube, often with a plastic collar in a color indicating the wire gauge, which is placed over the stripped end of a stranded wire and then crimped with a special crimping tool. This process, known as "crimping," firmly bundles the copper strands into a compact whole.

• The function of ferrules: Ferrules prevent the individual strands of a flexible cable from spreading, breaking, or making poor contact under a screw. This significantly improves the reliability of the connection and reduces the risk of overheating and short-circuiting.
• Crimping for a perfect connection: A properly crimped connection is both mechanically strong and electrically optimal. Always use the correct crimping tool specifically designed for ferrules and for the relevant wire gauge. This ensures the right pressure and deformation of the sleeve to create a solid connection.

Choosing the Right Material for a Durable Installation

Besides the type of connector, material properties of both the conductors and the connection material are crucial. The NEN 1010 standard, the leading standard for low-voltage installations in the Netherlands, imposes strict requirements on this. A proper installation starts with understanding the wire colors and their function, and their compatibility with the connection material.

Understanding Safety and Wire Colors

For a safe electrical installation, the standardization of wire colors is essential. This ensures that anyone working on the installation can immediately recognize the function of each wire. Any deviations may lead to dangerous situations.

Always ensure that wires with the same function are connected together. Connect a brown wire to a brown wire, a blue to a blue, and so on. This prevents short circuits and dangerous situations.

Wire Thicknesses and the NEN 1010 Standard

The diameter of electrical wires, expressed in square millimeters (mm²), determines the maximum current that can safely be carried. An undersized wire for a high current load can lead to overheating and fire.

• Minimum requirements: According to the NEN 1010, sockets must be connected with installation wire of at least 2.5 mm². For lighting, 1.5 mm² is often sufficient.
• Circuit protection: Each group in your distribution board is protected with a circuit breaker or fuse that disconnects in case of overload. The wire thickness must always match the protection rating of the group, to ensure the breaker trips before the wire overheats.

When selecting connection materials, it is important that they are suitable for the corresponding wire gauge. Many connectors and plugs indicate the permitted wire sections on their packaging or the product itself.

Frequently Asked Questions about Connection Materials

When should I use a wire connector and when a terminal block?

In most cases, opt for a wire connector, especially for solid core (VD) wires and in situations where reliability and speed are crucial. Wire connectors offer a consistent, safe connection that is less dependent on manual skill.

Terminal blocks are still suitable for flexible wires, particularly when connecting lamps, but always use ferrules in that case. Avoid terminal blocks for connecting multiple solid wires under one screw or in scenarios where vibrations or strain may occur, as this may weaken the connection.

Can I reuse wire connectors?

Releasable wire connectors (with a lever, such as the WAGO 221) are designed to be reused multiple times, as long as they are undamaged. Standard push-in connectors without a lever are usually for single use only. Always check the manufacturer's instructions.

How do I strip wires correctly for connection materials?

The length of stripped copper is crucial for a good connection. Too much exposed copper may create a risk of short circuits, while too little can result in poor contact. Wire connectors often have a strip-length indicator on the side. For terminal blocks, about 8-10 mm of copper is sufficient, ensuring no bare wire is visible outside the terminal block when connected.

Choose Quality Connection Materials for a Safe and Durable Installation

Selecting the right connection materials and applying the correct installation techniques are fundamental to the safety and reliability of any electrical installation. Invest in high-quality components and always follow applicable standards and expert recommendations. A safe electrical connection starts with the right foundation.