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16 Posts in this encyclopedia categoryLadder extension forces
Testing the conductor pull-out forces as a destructive material test enables an initial assessment of the quality of a crimp connection. Depending on the conductor cross-section. (All data without guarantee)
Ladder types
A distinction is made between the following conductor types in power cables: Conductor rope, stranded rope, stranded strand, solid conductor, cross-stranded conductor, constant lay conductor, braided conductor, bundled conductor and corrugated conductor. Furthermore, conductor types are categorised according to the type of use into main conductors and neutral conductors or earth conductors. (All information without guarantee)
Latency time
Term for the time difference between receiving and forwarding data. The latency time is usually measured between the last bit received and the first bit sent. (All data without guarantee)
Laying temperatures
The cable temperature should not be below +3 °C during installation. Cables with sheathing and insulation are sensitive to bending and impact at low temperatures. (All data without guarantee)
Leakage current
Current that flows across the surface of an insulating material between mutually energised metal parts. Particularly if this is contaminated by conductive deposits (dust, moisture). (All data without guarantee)
Leakage current
Leakage current is the current flowing via the operational insulation of a load to earth or a foreign conductive part. It can occur as a pure active current or as an active current with a capacitive component. VDE 0700-1 "Safety of household and similar electrical appliances" specifies the following leakage currents: for appliances of protection class 0 and 0I 0.5 mA; for portable appliances of protection class I 0.75 mA; for fixed motorised appliances of protection class I 3.5 mA; for fixed heating appliances of protection class I 0.75 mA or 0.75 mA/kW, max. 5 mA; for appliances of protection class II 0.25 mA; for appliances of protection class III 0.5 mA When considering leakage currents for an entire system (important e.g. also for RCDs), the leakage current (residual current) of the wires must be taken into account in addition to the leakage current of the consumables. (All data without guarantee)
Letter labelling
Labelling of wires and cables in the form of letters and numbers: according to their structure, nominal cross-section and number of cores, nominal voltage and conductor shape. The meaning of the letters and numbers is defined in standards and regulations (DIN, VDE). (All information without guarantee)
Limit temperature
The limit temperature is the sum of self-heating (including contact heating) and ambient temperature. The upper limit temperature is the highest permissible temperature at which a component may still be operated. Lower and upper temperatures that do not lead to damage to the materials. In between is the so-called operating temperature range (all information without guarantee).
Line abbreviation
Labelling of wires and cables according to their structure, nominal cross-section and the number of cores, nominal voltage and conductor shape, which is done by adding predetermined letters and numbers. The meaning of the letters and numbers is defined in standards and regulations. (All information without guarantee)
Line resistance
The line resistance counteracts a short-circuit current. With low-power voltage sources, a short-circuit current can be limited by the line resistance in such a way that a protective device no longer recognises this current as a short-circuit current. For example, the upper tripping limit of miniature circuit-breakers with a C characteristic is significantly higher than the rated current. For this reason, these protective devices in particular may switch off with a delay in the event of a short circuit. (All data without guarantee)
Locking bolt
For coding, to avoid mismating when several identical connectors are mounted next to each other.
Loop resistance
The sum of the DC resistances of two cores. The forward and return line of a cable circuit. (All data without guarantee)
Loss factor
The dissipation factor depends on frequency, temperature and capacitance. This factor is the ratio of active power to reactive power at sinusoidal voltage. (All data without guarantee)
Low voltage cable
The core insulation of a low-voltage cable is made of XLPE or PVC. The cables, which normally always consist of several cores stranded together to form a bundle, have a common core sheath (rubber compound) and an HDPE or PVC sheath over the bundle. The number of cores depends on the intended use.