Leiterklemmen im Vergleich: WAGO, Reihen- & Lüsterklemmen

Terminal Blocks Compared: WAGO, Rail & Lustre Terminals

Wire connectors are the underestimated heart of every clean electrical installation – and that's precisely why a closer look is worthwhile. Whether it's a WAGO push-in connector, a classic terminal block, or a rail-mounted terminal block: the right connection determines the safety, clarity, and longevity of your system. In this guide, we'll show you which connector fits when, which standards apply, and which mistakes you can avoid.

What are wire connectors?

Wire connectors are electrical connecting elements that allow you to safely connect two or more conductors without tools or by screwing. They replace twisting or soldering and also ensure a standard-compliant, gas-tight contact point according to DIN EN 60998 (IEC 60998). They are available as push-in connectors with spring force, as classic screw terminals (terminal blocks), and as rail-mounted terminal blocks for distribution board construction.

In short: A wire connector creates a permanent, detachable, or non-detachable connection between conductors – completely without a soldering iron and without the risk of loose wire ends. Thanks to modern spring-clamp technology, even fine-stranded wires can now be safely connected without the need for ferrules every time.

What types of wire connectors are there?

You'll find an astonishing variety on the market. However, electrical installations essentially distinguish between five main groups. This quickly allows you to identify the right design for your application. In addition, the following overview helps with direct comparison.

  • Push-in connectors (e.g., WAGO 221/2273): Spring-clamp technology, tool-free, ideal for junction boxes. You simply insert the stripped conductor into the connector – the spring holds it permanently and securely.
  • Terminal blocks / strip connectors: Classic plastic screw terminals. Inexpensive, widely used, but sensitive to overtightening and unsuitable for fine-stranded wires without ferrules.
  • Rail-mounted terminal blocks: Modular terminal blocks for distribution cabinets. They are available as through-connectors, disconnecting terminals, PE terminals, or N terminals. Perfect for neat wiring in control cabinets.
  • Main line terminals: Large-cross-section terminals for house connections – typically up to 35 mm² or 50 mm². They connect incoming main lines with outgoing lines in the meter cabinet.
  • Butt and crimp connectors: Non-detachable connections with crimping pliers, often used outdoors or with flexible cables.

WAGO connectors vs. terminal blocks: What's the difference?

At first glance, both serve the same purpose: connecting conductors. In practice, however, they differ significantly in handling, safety, and application area.

WAGO connectors (or spring-clamp connectors in general) use spring force to automatically clamp the conductor. You don't have to tighten a screw, and the clamping force remains constant for years – even if the conductor slightly deforms due to heating. This keeps you on the safe side, even with aluminum or fine-stranded wires.

Terminal blocks, on the other hand, rely on two grub screws per connection point. They are inexpensive but more prone to errors: overtightening can damage the conductor or break the polyamide housing. In addition, the clamping force decreases over time as temperature changes slightly loosen the screw. Experience shows that these are exactly the terminals you find in old junction boxes with burnt wires.

For new installations, many electricians today therefore opt for push-in connectors – faster, safer, and with reproducible quality. In existing systems, for lamp connections, or for small repairs, terminal blocks still have their place. Furthermore, for punctual repairs, they are often the quicker solution.

Which wire connector suits which application?

The right choice of connector depends primarily on where you are installing, what type of conductor you are connecting, and what requirements the system places. The cross-section and number of conductors also play a role.

In the junction box of residential installations, push-in connectors like the WAGO 221 are the first choice today. Depending on the model, they can accommodate up to five conductors from 0.2 mm² to 6 mm² – mixed fine-stranded and solid. In addition, their transparent housing allows for visible control of the insertion depth.

In the distribution cabinet, rail-mounted terminal blocks dominate. They enable a clear wiring concept, labeling, and easy expansion. In larger systems, you will also find N and PE disconnecting terminals that facilitate disconnection for measurements.

For house connections or the distribution of large cross-sections, main line terminals are used. They are designed for cross-sections up to 50 mm² and are therefore usually sealable. In outdoor or damp environments, you also need a suitable junction box with at least IP 54 or IP 65 – the connector alone is not enough.

What standards apply to wire connectors?

Wire connectors must be tested and certified according to international standards. You should be familiar with the most important standards so that you can identify the correct product if in doubt. This will also help you recognize whether a connector is tested just by looking at the box.

  • DIN EN 60998-1 / IEC 60998-1: General requirements for connecting devices up to 450/750 V.
  • DIN EN 60998-2-1: Requirements for screw-type connecting devices.
  • DIN EN 60998-2-2: Requirements for screwless-type connecting devices (spring-clamp).
  • DIN EN 60947-7-1: Terminal blocks for industrial applications (DIN rail).
  • DIN VDE 0606: Connecting devices for low voltages (national).

When purchasing, also look for the VDE or ENEC test mark, as well as the specified permissible cross-section and rated voltage. You should also check the clamping direction and maximum current carrying capacity. Cheap no-name connectors without a test mark are a safety risk in an emergency and simply not permitted in commercial systems.

Which errors occur most frequently in practice?

In practice, the same connector "sins" are repeatedly observed during inspections of existing installations. Most of these can be easily avoided – if you know about them. In addition, experience shows that many damages can be traced back to just a few standard errors.

  • Too short stripping length: The conductor is not inserted far enough into the terminal. Consequence: poor contact, heating, scorching. Most manufacturers print the stripping length directly on the terminal.
  • Fine-stranded wire without ferrule in screw terminals: Individual strands protrude, making the contact unreliable. A crimped ferrule should be used here.
  • Mixing different metals: Copper and aluminum should not be in the same screw terminal without a specially approved terminal model. Otherwise, contact corrosion threatens.
  • Overloading the terminal: Too many conductors, too large a cross-section – always check the manufacturer's specifications.
  • Terminals embedded in plaster or buried under plaster: Prohibited! Terminal connections must remain accessible at all times, meaning they must be in a junction box.

Spring-clamp or screw terminal: Which is technically better?

The central question for modern wire connectors is: spring force or screw? Both systems have their justification, but differ significantly in detail.

Spring-clamp terminals generate the contact force via a pre-tensioned stainless steel spring. This spring automatically compensates for thermal changes in the length of the conductor, so the clamping force remains constant over the entire service life. In addition, the processing is reproducible – whether apprentice or master electrician: The conductor is always held with the same pressure. Especially in the case of vibrations, for example in industrial systems or with wallbox installations with frequent load changes, this is a clear advantage.

Screw terminals, on the other hand, score points with large cross-sections from about 16 mm². Here, they provide higher contact forces than any spring, which is why main line terminals are traditionally screwed. In addition, they are unbeatable in price if only a few connections need to be made. Furthermore, high-quality screw terminals with wire protection brackets also allow clamping of fine-stranded conductors without ferrules – provided the correct model is used.

Rail-mounted terminal blocks with jumpers: How does this save wiring work?

In distribution board construction, rail-mounted terminal blocks with jumpers are a real time-saver. Instead of wiring each terminal individually, you insert an insulated cross-jumper with two, three, or ten poles over adjacent terminals. This connects all N-conductors of a circuit in seconds – neatly, with permanent contact, and without wire clutter.

Jumpers are available as plug-in, screw, or comb jumpers. Make sure that the jumper matches the terminal manufacturer and type – mixing crosswise is not a good idea. Experience shows that jumpers save up to 30% wiring time in larger distribution boards.

How do you choose the right wire connector?

Before you grab the next box, it's worth taking a quick look at four key criteria. This checklist will help you find the right terminal block in the hardware store or webshop at a glance.

  1. Clarify conductor type and cross-section: Solid or flexible? 1.5 mm², 2.5 mm² or 6 mm²? The terminal must match the conductor type and size.
  2. Determine the number of conductors: How many conductors do you want to connect? Push-in connectors typically have 2, 3, or 5 connections.
  3. Check the place of use: Indoors, damp rooms, distribution board, or outdoors? This also determines the required junction box with IP protection class.
  4. Check test marks and standards: VDE, ENEC or equivalent – plus specification of the approved rated voltage.

If you are unsure, err on the side of caution and choose the higher category – it's better to take a terminal for 6 mm², even if you only connect 2.5 mm². This gives you a reserve and you don't have to replace everything during the next renovation.

Frequently Asked Questions

Are WAGO connectors better than terminal blocks?

For new installations, push-in connectors like the WAGO 221 are generally the better choice – they are faster to process, maintain constant clamping force, and also accept fine-stranded conductors without ferrules. Terminal blocks are cheaper and still permissible for simple lamp connections or repairs, but are more prone to errors in processing.

Which wire connector do I need for fine-stranded wires?

For fine-stranded wires, spring-clamp terminals like the WAGO 221 or 2273 are recommended, which explicitly permit fine-stranded conductors according to the data sheet. If you use screw terminals, a crimped ferrule must be applied to the strand – otherwise, the connection is neither mechanically nor electrically safe.

How many conductors can a terminal accommodate?

This depends on the model and is stated on the terminal or in the data sheet. Typical push-in connectors have 2, 3, or 5 connections, while rail-mounted terminals usually have 2 (through-connection) plus jumper options. Important: never insert two conductors into a clamping point intended for only one conductor.

Are terminal blocks still permissible today?

Yes, terminal blocks according to DIN VDE 0606 are still permissible in Germany and Austria, provided they are used correctly. In practice, however, they are increasingly being replaced by spring-clamp terminals because these are more reproducible and safer to process.

Do WAGO connectors require a junction box?

Yes, all terminal connections must remain accessible at all times and be located in a suitable junction box. It is not permitted to embed them in plaster or behind closed walls – not even with the best WAGO connector.

Conclusion

Wire connectors may seem simple, but they are the backbone of every safe electrical installation. Those who correctly combine push-in connectors for junction boxes, rail-mounted terminals for the distribution board, and main line terminals for the house connection build systems that are clear, safe, and durable. Pay attention to VDE test marks, suitable cross-sections, and clean stripping – then the connection will last for decades.

In the techarena24.shop, you will find a wide selection of tested connecting terminals for every application – from individual push-in connectors to complete rail-mounted terminal sets for distribution board construction.

Note: Work on electrical systems may only be carried out by trained electricians.

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