5 Automatic disconnection supply
The verification the efficacy the measures for protection against indirect contact by
automatic disconnection supply effected follows:
a) For systems
Compliance with the rules for systems shall verified by:
1) measurement the loop impedance. The testing apparatus shall capable
of supplying the test voltage specified Table 9.
9.
9.1 when loaded with mA.3.3. alternative compliance may verified by
measurement the resistance protective conductors.
(V)
Insulation
Resistance
(MΩ
Ω
Ω
Ω)
SELV and functional extra-loe voltage, when the circuit supplied
froma safety transformer and also fulfils other requirements
250 ≥0.3 Protection separation circuits (electrical separation)
The separation the live parts from those other circuits and from earth shall verified
by measurement the insulation resistance.
9.
Note: This precaution necessary because carrying out the test without connection between live conductors
could cause damage electronic devices.
Table 9.4 Polarity test
Where the rules forbid the installation single pole switching devices the neutral
conductor, test polarity shall made verify that all such devices are connected the
phase only.5
Above 500 1000 ≥1.
Note: The above measurements are not necessary where the calculations the fault loop impedance the
resistance the protective conductors are available and when the arrangement the installation permits measuring
.3. The resistance values obtained shall in
accordance with Table 9.VERIFICATION ELECTRICAL EQUIPMENT AND INSTALLATION 85
The insulation resistance, measured with the test voltage values indicated Table 9.1 Minimum value insulation resistance
Nominal circuit voltage
(V)
Test voltage
d.25
Up and including 500 with the exception the above cases 500 ≥0.
When the circuit includes electronic devices, only the measurement between phases and
neutral, connected together, earth shall made.1, with the appliances, far possible, connected.0
Measurement shall carried out with direct current.c.1, is
satisfactory each circuit, with the appliances disconnected, has insulation resistance not less
than the appropriate value given Table 9.1
