Unitest Telaris 0100, Instruction Manual

Page: 39 / 108

English
5.5 General Information about RCD Tests
The contact voltage UB and the trip time t required
by the RCD to disconnect the subsequent current
circuit from the mains represent important mea-
surement units for the asessment
of an RCD.
For this reason, IEC 60364 prescribes that
a) the maximum allowable value for the contact
voltage (25V/50V) may not be exceeded within
any system during tripping at nominal residual
current.
b) the RCD must trip within a time limit of 300ms.
The task of an residual current device (RCD) con-
sists in switching off a system within a defined time
period after an error prior the contact voltage reach-
es the permissible limit value of 25V / 50V.
The system testing should be started by carrying out
a visual inspection, in particular of the protective
earth connection.
1. Within the IT system, the protective earth con-
ductor doesnot have to be connected with the
PEN but with the protective earth connection.
2. The protective earth conductor must be connect-
ed to the PEN prior to the RCD within the TN sys-
tem.
3. An insulation measurement as described in Sec-
tion 5.2 must be performed. In particular it must
be proofed, that there is no connection between
N and PE following the RCD.
4. Proof regarding the low impedance connection of
equipotential bonding conductors in compliance
with Section 5.4 must be available.
Time-delayed residual current devices trip at
nominal residual current within 130…500ms,
for double nominal fault current within
60…200 ms. Such RCDs are im-plemented as
main residual current protection devices
(please refer to IEC 61008-1) and are marked
with the symbol
“ S ” .
The contact voltage represents the voltage pre-
sent during an insulation error between two si-
multaneously touchable components.
At a measuring circuit without probe, available
voltages between PE and earth can influence
the measurement.
At use of the N-conductor as probe, the N-con-
ductorshould be check first of all of correct and
low-ohm connection to neutral point of sys-
tem. A available voltage of the N conductor to
the arth can influence the measurement.
The mneasuring function uses the N-conductor as
a probe. Check first the connection between the
neutral point of the distribution system and earth
before the test is started. A possible voltage be-
tween the N-conductor and earth may influence the
measurements.
Leakage currents by preconnected loads can
influence the measuring.
Attached loads or operating supplies which
contains capacitors or circulating machines
can elongate the trip time.
Any test and measurement procedures in cir-
cuits equipped with residual current devices
should only be performed after having con-
sulted the operator terminals (data processing
systems, material processing, motors, etc.).
For measurements on earthed sockets or
equipment with protective conductor connec-
tion, the protective earth must be checked for
correct connection by touching contact elec-
trode "PE". If an error is indicated via the sock-
et error symbol (6), the PE connection must be
checked ! The user may only start the test, once
the protective conductor is properly connect-
ed.
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General Information about RCD Tests