Benning ST 725 - Testing Procedure

07/ 2018 BENNING ST 725

28
- If the external conductor (L) and the neutral conductor (N) of the shock-proof socket
have been inverted or the voltage potentials are outside the following limits, an will be
displayed next to the LE and NE symbols.
LN 195 V - 253 V
LE 195 V - 253 V
NE < 30 V

Only the voltage potentials between the individual connections L, N and PE are
measured. The measurement does not provide any information on the proper
installation of the shock-proof socket. There will be no warning in case of a
dangerous contact voltage of the PE conductor!
The BENNING ST 725 must not be permanently connected to the mains voltage!
- After approx. 3 seconds, the BENNING ST 725 automatically switches to stand-by mode.
Seegure3: Voltagemeasurementonexternalshock-proofsocket
8.4 Testing procedure
The BENNING ST 725 is intended for electrical safety tests according to DIN VDE 0701-0702
and ÖVE/ ÖNORM E 8701. Please refer to the current version of the standards for detailed
information concerning the tests and limiting values.
Automatically,theBENNINGST725veriesthetypeoftheconnectedtestobjectandinforms
the user in case of incorrect preselection of the testing procedure [
2
...
3
].
Note:
- The BENNING ST 725 can be used for tests in battery operating mode and in mains
operating mode with connection of a mains voltage of 230 V. In battery operating mode, it
has to be observed that the protective conductor current and contact current measurement
is carried out by means of the alternative leakage current measurement method. This
method is appropriate for test objects which do not contain any mains voltage-dependent
switching elements (e.g. mains supply units).
- If the internal structure of the test object is not known or if it contains mains voltage-
dependent switching elements, the test has to be carried out in mains operating mode with
connection of a mains voltage of 230 V. As soon as the BENNING ST 725 is supplied with
mains voltage via the jack K, the protective conductor current/ contact current measurement
will be carried out automatically by means of the differential current/ direct measurement
method under operating conditions of the test object.
- The testing voltage for insulating resistance measurement is preset to 500 V
DC
according
to the applicable standard. For test objects with integrated overvoltage arresters and for
electronic devices for which there are objections regarding a testing voltage of 500 V
DC
, the
testing voltage can be reduced to 250 V
DC
by means of the -key
5
.
9. Testing of electrical devices / equipment according to DIN VDE 0701-0702 and ÖVE/
ÖNORM E 8701

Prior to test, a visual inspection of the test object has to be carried out. In case
of possible damages, the test must be stopped.
9.1 Testing of devices of protection class I 
Testing of devices with protective conductor and accessible conductive parts which are con-
nected to the protective conductor.
- Connect the test object to the test socket
1
of the BENNING ST 725.
- Plug the 4 mm safety plug of the test lead with alligator clip into the 4 mm safety socket
9
and establish a connection with a metal part of the test object.
- For mains operating mode (protective conductor current by means of differential current
measurement method, test object in operation!): Connect the plug of the mains connection
cable with the socket K and the shock-proof plug with a protected shock-proof socket
(230 V, 50 Hz, 16 A).
- If necessary, the testing voltage of the R
ISO
(insulating resistance) measurement can be
reduced to 250 V
DC
by means of the -key
5
. The selected testing voltage is briefly shown
on the display
8
. Press the key again to switch back to the preset testing voltage of 500 V
DC
.
- Switch the test object on.
- Press the -key
2
to start the automatic testing procedure.
- The test starts with measuring the protective conductor resistance R
PE
.
- If R
PE
ishigherthan1Ω, themeasuredvalueofR
PE
will be shown on the display and a
will appear next to the R
PE
symbol. "FAIL" appears on the display to confirm that the
measurement has been stopped.