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Quick & safe error-free connector installation

Whether in distribution boxes, lighting connections, or household appliance wiring – a clean and secure connector is essential for reliable function and safety. Still, mistakes commonly happen in practice – even though they’re easy to avoid.

Our tips explain why the SDKF lever connector from Electro Terminal is gradually replacing screw-type connectors and how you can prevent typical installation errors. Avoid loose connections, insulation faults, and outages – and ensure maximum safety in just a few seconds.

Common mistakes during connector installation

Incorrect stripping length

If you strip the wire too short or too long, it may result in poor contact or exposed conductors. Use the integrated stripping gauge on the SDKF housing to check the stripping length.

Wire not fully inserted

The SDKF features an inspection window. Check the window to verify that the wire is fully inserted into the connector.

Incorrect torque applied

If the torque is too tight or too loose that can compromise the connection. For screw connectors like the EKL S, follow the values in the datasheet (e.g. 0.5–0.6 Nm).
With lever connectors like the SDKF, the clamping force is controlled by an internal spring. This automatically ensures consistent pressure. You only need the lever to open and close the contact.

Lever not fully closed

Closing the lever is intuitive: Press it all the way down until it clicks. You will feel and often even hear the click. The required contact pressure is automatically applied by the internal spring, regardless of how firmly the lever is pushed.
A lever that is not fully closed may open unintentionally, for example if a solid wire presses against it when closing the junction box.

Incompatible wire cross-section

Only use wires within the specified range (e.g. SDKF: 0.2–2.5 mm²). Outside this range, reliable contact cannot be guaranteed.

No visual inspection and pull test

Every connection should be tested after wiring – regardless of the connector type.

Please note:

Mechanically damaged or corroded wires can also affect connection reliability. The above points are just a selection of possible error sources. If you need help choosing the right connector or using it correctly, we’re happy to assist you.

Installation Checklist

Pre-installation check

  • Is the connector suitable for the wire type and cross-section?
  • Does the connector match the wire type, voltage, and ambient temperature?
    → Download the datasheet from the product detail page, e.g. SDKF | Electro Terminal.


Visual check
After connecting the wire, visually confirm that:

  • The wire is fully and correctly inserted into the connector.
  • No strands are sticking out and no bare wire is visible outside the connector.
  • The connector and, where applicable, the lever are intact and fully closed.


Why?
This helps you identify mounting errors that could lead to poor contact, short circuits, or failures later on.

Pull Test
After wiring, pull each wire gently but firmly to confirm:

  • Is the wire held securely in the connector?


How to do it:
Grip the wire by its insulation directly in front of the terminal and pull briefly and firmly – similar to unplugging a device. The terminal must not release the wire.

Why?
Only this way can you ensure that the mechanical connection is secure. Loose or unstable contacts are a frequent cause of malfunctions or, in the worst case, fire hazards.