Screw terminal

A terminal block, in Austria also Luster terminal block terminal or terminal, in Switzerland, candlesticks terminal is used to connect two or more, stranded in general, electric cable.

Origin of the name

Wire nuts are so called because they can (generally so in particular chandeliers and ceiling lights ) are used in particular in the assembly of chandeliers.

Design and function

The terminal block is made of insulating plastic or ceramic case, this surrounds a tubular profile made of an electrically conductive material, usually nickel-plated brass. This profile is provided with one or two threaded holes in which simple or cross-slitted studs that were clamping screw them. This hollow profile, the stripped ends of the individual wires are inserted and fixed by clamping screws.

The ends of stranded wires with ferrules have to be inserted, so the risk of mechanical damage and breakage of single strands by rotating the clamping screw is excluded.

Not allowed is a tinning the wire ends with solder, because the solder flow under the mechanical pressure of the clamping screw and loosen so would, which would be a security risk, once tendency to overheat under normal conditions, electrical load to fire form because of less contact quality, on the other hand by complete loss of contact or even mechanical slipping with additional short circuit.

Depending on the application luster terminals are commercially available in various sizes.

Guidelines for use

When using wire nuts or implement the installation must be checked in each individual case whether the situation for the application of each applicable VDE standards are adhered to. Wire nuts or other loose clamps are not approved for connection of conductors in distribution, since it certain demands can not be met. There are to be used permanently mounted terminal blocks or terminal strips.

Types and Uses

Luster terminals are now mostly replaced with new installations professionals by spring terminals, as these terminals do not require ferrules, which must be used when connecting fine-wire line otherwise; also eliminates one phase, assembly is very fast and has thus despite the higher terminal costs a cost advantage. Due to the continuously existing spring clamp and the self-locking in tension loosens the connection not even after many years.

In low-voltage halogen lighting systems inherently occur on relatively high currents. Because of the then possible warming of defective contact points as a result of contact resistance wire nuts are often used in a heat-resistant version. For use in oven Outlets there are load- resistant designs. Better, however, are universal spring-loaded terminals for different conductor types that allow fast, hassle and more persistent compounds.

In addition to the illustrated double-breasted design with two clamping screws per pole there are also single row with a single screw. Terminal rows of soft or hard plastic are usually twelve pole and can be cut with a knife blade or saw, as required in the appropriate parts (usually two, three or four poles ). It should be noted that the thickness of the insulation must be retained laterally. Because connections through the terminal screws are easily detachable, can be realized with screw-type terminals also experimental setups, such as the electronics tinkering.

Doses Lüsterklemme

A special form represents the doses terminal block (also Dolü, doli or Dosenklemme ), constructed space-saving and therefore has only one clamp screw; there they are open on both sides or one side closed. Your originary and eponymous of use is the junction box.