Luster terminal

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Luster terminals

A terminal block in Austria screw terminal , block terminal or terminal , in Switzerland and candlesticks terminal , in Bavaria also clamping block is a terminal for connecting single- or multi-conductor electrical cables . The name of the luster terminal refers to the electrical connection of chandeliers and other ceiling lights.

Layout and function

The luster terminal consists of an insulating plastic or ceramic housing , which surrounds a tubular profile made of an electrically conductive material, usually nickel-plated brass . This profile is provided with one or two threaded holes into which single- or cross-slotted studs , which serve as clamping screws , were screwed. The stripped ends of the individual lines are inserted into this hollow profile and fastened with the clamping screws.

The ends of stranded wires must be inserted with end sleeves , so that the risk of mechanical damage and breakage of the individual strands due to the rotating clamping screw is excluded. However, there are now luster terminals with wire protection in which the strands are fixed by a small plate that is pressed down by the screw. No ferrules are then required for this.

Tinning the strand ends with tin solder is not permitted , as the solder would flow under the mechanical pressure of the clamping screw and thus loosen, which would represent a safety risk, on the one hand due to the tendency to overheat under normal electrical loads and on the other hand to fire due to poor contact quality due to complete loss of contact or even mechanical slipping with additional risk of short circuits. Depending on the wire thickness, luster terminals are available in different sizes.

Types and uses

Various terminals,
in the middle and on the far right luster terminals of various sizes and numbers of positions
Experimental setup with luster terminals and a soldering strip (top center) from the 1960s

Luster terminals made of soft or hard plastic are usually offered as a twelve-pole strip that can be cut into suitable parts (usually two, three or four poles) as required. When cutting, make sure that the side insulation on the terminal block remains intact, i.e. only the connecting webs are cut.

In house installations, you can find luster terminals in connection canopies of ceiling or wall lamps. They are also often used for variable experimental set-ups such as electronic tinkering, as they create a clear and easily detachable connection.

During electrical work by skilled workers, luster terminals found are often replaced by spring-loaded terminals , which create a connection that is significantly safer and easier to process at slightly higher costs. Due to the permanent spring clamping and the self-locking in the event of tensile stress, such a connection, in contrast to a screw clamping, does not loosen in the long term.

In low-voltage halogen lighting systems with its characteristic high currents may in poor contact points to significant heat generation due to contact resistances come. Therefore, heat-resistant luster terminals are preferred here. There are load-resistant versions for use in stove connection sockets such as those available in Germany. However, universal spring-loaded terminals for different types of conductors are also better here, as they enable fast, uncomplicated and particularly long-lasting connections.

Can luster terminal

A special form is the can luster terminal (also DoLü, DoLi or can terminal), which is built to save space and has only one clamping screw; they are open on both sides or closed on one side. Their original and eponymous place of use is the junction box .

Usage guidelines

Before using luster terminals, it must be checked in each individual case whether the guidelines applicable to the application are being observed. In Germany, for example, according to VDE standards, luster terminals or other loose terminals are not permitted for connecting conductors in distributors , as certain requirements cannot be met with them. There are permanently mounted terminal blocks or terminal strips to be used.

literature

  • Alfred Hösl, Roland Ayx, Hans Werner Busch: The electrical installation in accordance with regulations, residential construction, commercial industry. 18th edition, Hüthig Verlag, Heidelberg 2003, ISBN 3-7785-2909-9 .

Individual evidence

  1. Compare DIN VDE 0100-520; VDE 0100-520: 2013-06: Erection of low voltage systems - Part 5: Selection and erection of electrical equipment; Chapter 52: Cable and wire systems
  2. H. Senkbeil: Connection terminals in distributors . In: electrical practitioners . Berlin. 56th year (2002). No. 11. P. 903
    H. Senkbeil: Loose connection terminals in distributors . In: electrical practitioners . Berlin. 58th year (2004). No. 3. P. 192
    The answers refer to:
    1.) DIN VDE 0100-510: 2011-03: Installation of high-voltage systems with rated voltages up to 1000 V; Selection and installation of electrical equipment; General provisions. : According to Section 513.1 Equipment shall be located so that "are their operational use, their inspection, their maintenance and access to the detachable connections easy."
    2.) DIN VDE 0100-520: 2013-06 Erection of power installations with nominal voltages up to 1000 V; Selection and installation of electrical equipment; Cable and line systems. : In section 526.3, the same accessibility is required and the possibility of a test is also pointed out.
    3.) DIN VDE 0100-729: 2010-02: Installation of high-voltage systems with nominal voltages up to 1000 V; Setting up and connecting switchgear and distribution boards : According to point 4.4, the assignment of the external conductors to their circuits must be clearly and permanently recognizable. (Either through terminal blocks or through direct installation on the circuit breaker.)

Web links

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