5.7 Testing the Trip Time and the
Contact Voltage
The instrument UNITEST 0100-ELECTROcheck
tests the trip time and the contact voltage in sys-
tems with built-in RCDs. A contact voltage test is
performed prior to trip time testing. Following this
test, the residual current circuit breaker is tripped
by applying a nominal fault current and the respec-
tive trip time is checked.
Simultaneously, the earthing resistance of the L-PE
loop is calculated. For this purpose, the contact volt-
age measured is divided by the nominal fault cur-
rent (RE=UB/I
Δ
N).
In accordance with the nominal fault current set via
the residual current circuit breaker, the maximum
earthing resistance is monitored in addition to the
contact voltage measured. Please refer to table 1 on
page 23.
For residual current circuit breaker tests,
please respect the references in section 5.5
'General Information Regarding RCD Tests'.
If a contact voltage exceeding 25 V is measured
during RCD test, the test is immediately inter-
rupted and the test instrument shows the “
” (14) and 'contact voltage' (15) symbols, in
compliance with Figure 5.7.1.
Figure 5.7.1:
Display for excessive contact voltage
Performing the test
Connect the desired test lead (either test lead with
shockproof plug or three individual test leads) to
the UUT. Connect the black test lead to the black
socket 'L/L1' (24), the blue test lead to the blue
socket 'N / L2' (25), and the green test lead to the
green socket 'PE / L3' (26).
Switch on the UNITEST 0100-ELECTROcheck
using the rotary switch 'Measurement Function'
(19). In accordance with the respective nominal
fault current of the RCD under test select the ap-
propriate measurement function using the rotary
switch, e.g. 'RCD 30 mA'. The test instrument
displays as follows:
Figure 5.7.2: Instrument ready for operation
Now connect the test leads to the UUT; please
refer to Figure 5.7.3 or Figure 5.7.4 for connec-
tion.
26
Testing the Trip Time and the Contact Voltage
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