Kyoritsu 6010B User Manual download pdf (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 RCD, e.g. capacitors or rotating

machinery, may cause a significant lengthening of the measured

trip time.

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Kyoritsu 6010B User Manual Page 28