KYORITSU 6010B - Manual (Page 28)

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8.7 Testing time delayed RCDs
RCDs with a built-in time delay are used to ensure discrimination, that is, that
the correct RCD operates first. Testing is carried out in accordance with item 8.6
above, except that the displayed tripping times are likely to be longer than those
for a normal RCD. Since the maximum test time is longer, there may be danger
if earthed metal is touched during the test.
MAKE SURE TO KEEP CLEAR OF EARTHED METAL DURING THE
OPERATION OF THIS TEST.
Note:
● KEW 6010B calculates the Uc voltage with the impedance measured, and if
the calculated Uc voltage exceeds UL, KEW 6010B indicates the warning
"UcH v" on the LCD and stops the measurement. If the value is less than UL,
the unit proceeds with the measurement of a RCD.
● If the IΔN setting is grater than the rated residual operating current of the
RCD under test, RCD will trip and "no" may be displayed on the LCD.
● If the RCD does not trip the tester will supply the test current for a maximum
of 2000ms on the X1/2 and X1 ranges. The fact that the RCD has not tripped
will be evident because the P-E and P-N LEDs will still be on.
WARNING
● If a voltage exists between the protective conductor and earth, it
may influence the measurements.
● If a voltage exists between neutral and earth, it may influence the
measurements, therefore, the connection between neutral point of
the distribution system and earth should be checked before
testing.
● Leakage currents in the circuit following the RCD may influence
the measurements.
● The potential fields of other earthing installations may influence
the measurement.
● Special conditions of RCDs of a particular design, for example S-
type, shall be taken into consideration.
● Equipment following the R C D, e.g. capacitors or rot ating
machinery, may cause a significant lengthening of the measured
trip time.