b) For systems
Compliance with the rules for systems shall verified by:
1) measurement the resistance the earth electrode for exposed conductive parts the
installation;
2) verification the characteristics the associated protective device. that case the verification the continuity the
protective conductors sufficient
2) verification the characteristics the associated protective device (i. visual
inspection the nominal current setting for circuit-breakers and the current rating for fuses and
also test for residual current protective devices). This verification
shall made:
- for residual current devices visual inspection and test;
- for overcurrent protective devices visual inspection (i.
Measurement fault loop impedance
Measurement the loop impedance shall effected the same frequency the nominal
frequency the circuit.
Where conditions similar conditions similar conditions systems occur,
verification made according point this clause.
Note: During the measurement the loop impedance, necessary establish connection negligible
impedance between the neutral point the system and the protective conductor the origin the installation.
Measurement the resistance the earth electrode
Measurement the resistance earth electrode, where prescribed, made an
appropriate method.
2.e.
Precautions are taken while making this measurement order avoid the danger due double fault. current setting for circuit-
breakers, current rating for fuses);
- for the protective conductors inspection their continuity. The measurement made only the calculation not possible, because all the parameters are not known.
Where conditions, which are similar conditions systems, occur the event a
second fault, verification made according point this clause.
c) For systems
Calculation measurement the first fault current.
In addition, the effective earthing resistance the system shall verified where
necessary.VERIFICATION ELECTRICAL EQUIPMENT AND INSTALLATION
86
of the length and cross-sectional area the conductors. This measurement not necessary all exposed conductive parts the installation are connected the
power system earth the case where the system connected earth through impedance.
Notes:
1.
.e
