GMC-I Messtechnik GmbH
17
7.2
Special Testing for Systems and RCCBs
7.2.1
Testing Systems and RCCBs with Rising Residual Current
(alternating current) for RCDs type A, AC and B
Measuring Method
The instrument generates a continuously rising residual current of
(0.3 ... 1.3)
I
N
within the system for the testing of RCDs.
The instrument stores the contact voltage and tripping current
values which were measured at the moment tripping of the RCCB
occurred, and displays them.
One of two contact voltage limit values, U
L
= 25 V or
U
L
= 50 V/65 V, can be selected for measurement with rising
residual current.
Select the Measuring Function
Connection
Set parameters for I
F
Start Measurement
Measuring Sequence
After the measuring sequence has been started, the test current
generated by the instrument is continuously increased starting at
0.3 times nominal residual current, until the RCCB is tripped. This
can be observed by viewing gradual filling of the triangle at I
.
If contact voltage reaches the selected limit value (U
L
= 65 V, 50 V
or 25 V) before the RCCB is tripped, safety shut-down occurs.
The U
L
/R
L
LED lights up red.
Note
Safety shut-down:
At up to 70 V, a safety shut-down is
tripped within 3 seconds in accordance with IEC 61010.
If the RCCB is not tripped before the rising current reaches
nominal residual current I
N
, the RCD/FI LED lights up red.
Attention!
!
If biasing current is present within the system during
measurement, it is superimposed onto the residual
current which is generated by the instrument and
influences measured values for contact voltage and
tripping current. See also section 7.1.
Evaluation
According to DIN VDE 0100, part 600, rising residual current
must, however, be used for measurements in the evaluation of
RCDs, and contact voltage at nominal residual current I
N
must
be calculated from the measured values.
The faster, simpler measuring method should thus be taken
advantage of (see section 7.1).
7.2.2
Testing Systems and RCCBs with Rising Residual Current
(direct current) for RCDs type B
In accordance with VDE 0413, part 6, it must be substantiated
that, with smooth direct current, residual operating current is no
more than twice the value of rated residual current I
N
. A continu-
ously rising direct current, beginning with 0.2 times rated residual
current I
N
, must be applied to this end. If current rise is linear, ris-
ing current may not exceed twice the value of I
N
within a period
of 5 seconds.
Testing with smoothed direct current must be possible in both
test current directions.
I
F
Nom. residual current:
10...500 mA
Type 1:
RCD, SRCD, PRCD ...
Nominal current:
6 ... 125 A
Type 2:
AC
, A
, B
*
* Type B = AC/DC sensitive
Sine
Negative/positive direct current
Waveform:
Connection:
Without/with probe
Type of system:
TN/TT, IT
Contact voltage:
Trip limits:
