Cable tester
A cable tester is used to test cables or wiring . Simple testers only test cable assignment and galvanic connection, high-quality cable testers can also measure insulation resistance and channel capacitance , as well as wave resistance .
Messaging
A cable tester can also be used to check the function of communication lines (see figure - Tester for network lines ). It can be checked, for example, whether the individual line pairs are electrically isolated from one another and whether communication with sufficient signal levels is possible via all line pairs .
Furthermore, the line impedance of the data lines can be checked with powerful test systems . If there is line damage, the short-circuit point between individual lines or the earth fault point can also be measured by means of alternating current measurement. In addition, line squeezing can impair data transmission via communication lines. The same is the case when communication lines are laid with a bending radius that is too small . In this case, the characteristic impedance of the line changes, so that the transmitted signal can be attenuated or reflected . This change in the wave resistance can be carried out with a wave resistance meter.
power supply
Before the commissioning of electrical lines for power supply , these must be checked and released. For example, consider a line with five individual wires. This has three outer conductors (L1, L2 and L3), neutral conductor (N) and protective conductor (PE). The electrical resistance of all five individual wires must be checked using an ohmmeter. In addition, the insulation resistance of all five conductors among each other must be checked by means of an insulation measurement. In order to produce a uniform clockwise rotating field, the rotating field of the three outer conductors must be checked by means of a rotating field measurement. Line testers offer these different measuring methods in a single measuring device.
In addition, in the event of a fault (e.g. short circuit between two or more conductors , earth fault in one conductor), a cable tester can be used to isolate the fault location by measuring the resistance ( direct current measurement or alternating current measurement ) so that the line does not have to be completely exposed.
