COMBITEST422
EN - 39
6.6. RCD:
TEST ON DIFFERENTIAL SWITCHES
This function is performed in compliance with standard IEC/EN61557-6, BS7671 17th/18th
edition and allows measuring the tripping time and current of molded-case differential
switches of type A (
) , AC (
) or B (
) being General (G) and Selective (S).
CAUTION
The instrument checks voltage on PE by comparing the voltage at B4 input
and the ground potential induced on the instrument
’s side through the user’s
hand. Therefore, in order to check voltage on PE,
it is mandatory to hold
the instrument case on the left or on the right side.
CAUTION
Some combinations of test parameters could be unavailable in compliance
with the technical specifications of the instrument and the RCD tables (
see
§ 10.1
–empty cells of RCD tables mean unavailable situations
).
The following operating modes are available:
•
AUTO
the instrument performs tripping time measurement automatically with a
leakage current equal to half, once or five times the set value of nominal
current and with a leakage current in phase with the positive (+) and negative
(-) half-wave of the mains voltage. Recommended mode for RDC test
•
AUTO
the instrument performs tripping time measurement automatically with a
leakage current equal to half, once or five times the set value of nominal
current and with a leakage current in phase with the positive (+) and negative
(-) half-wave of the mains voltage and also real tripping current
•
x½
the instrument performs tripping time measurement with a leakage current
equal to half the set value of nominal current with the positive (+) and
negative (-) half-wave of the mains voltage
•
x1
the instrument performs tripping time measurement with a leakage current
equal to once the set value of nominal current with the positive (+) and
negative (-) half-wave of the mains voltage
•
x5
the instrument performs tripping time measurement with a leakage current
equal to five times the set value of nominal current with the positive (+) and
negative (-) half-wave of the mains voltage
•
the instrument performs measurement with an increasing leakage current.
This test could be performed to determine the real tripping current of the
RCD with the positive (+) and negative (-) half-wave of the mains voltage
CAUTION
Testing an RCD causes the RCD’s tripping.
Therefore, check that there are
NO users or loads connected downstream of the RCD being tested which
could be damaged by a system downtime.
If possible, disconnect all loads connected downstream of the RCD as they
could produce leakage currents further to those produced by the instrument,
thus invalidating the results of the test.
