Benning ST 720 Bedienungsanleitung Seite 27

Insulating
resistance
R
ISO
Protective con-
ductor current
I / I
EA LEAK
Contact current
I / I
EA LEAK
8. Making measurements with the BENNING ST 720
8.1 Preparations for making measurements
Operate and store the BENNING ST 720 only at the specified storage and operating temperatures
conditions. Do not permanently expose the device to sunlight.
- Check rated voltage and rated current details specified on the safety measuring lines.
- Strong sources of interference in the vicinity of the BENNING ST 720 can lead to unstable
readings and measuring errors.
Before starting the BENNING ST 720, always check the device, the lines and the

test object for damages.
Please make sure not to exceed the maximum breaking capacity/ lamp load of
the test socket of the BENNING ST 720 (see chapters 7.4 and 7.5). Exceeding

the values might cause tripping of the fuses and damaging of the BENNING
ST 720. Damages due to overload are excluded from possible warranty claims.
The plug of the mains connection cable can be connected with the socket K
of the BENNING ST 720 in one position only (see white mark). Do not exert

force to the plug of the mains connection cable in order to avoid damaging of
the BENNING ST 720.

Before starting the test, switch the test object on (mains switch ON).
At the beginning of the test it has to be checked whether the selected testing

procedure complies with the protection class of the connected test object.
8.1.1 Switching the BENNING ST 720 ON/ OFF
- Press and hold the keys 2 and 3 for approx. 3 seconds to switch the BENNING ST 720 on.
Acoustic signals confirm that the device is switched on. Press the keys again to switch the
device off.
- After approx. 2 minutes, the BENNING ST 720 switches off automatically (APO, Auto
Power-Off). It switches on again when the keys 2 and 3 are pressed. An acoustic signal
indicates that the device has switched off automatically.
8.1.2 Testing the mains voltage on external shock-proof socket
- Connect the mains connection cable to the mains connection socket K of the BENNING ST 720.
- Connect the shock-proof plug to the shock-proof socket to be tested. With the mains voltage
being applied, the voltage measurement will start automatically.
- Depending on the external conductor position (right or left) of the shock-proof socket, the
voltage potentials between the connecting terminals L, N and PE will be shown on the dis-
play for approx. 3 seconds.
08/ 2010
≥ 1 MΩ
≥ 2 MΩ for proving safe
disconnection (transformer)
≥ 0.3 MΩ for devices with heating
element
≤ 3.5 mA
on conductive parts with
PE connection
1 mA/ kW for devices with heating
elements P > 3.5 kW
≤ 0.5 mA
on conductive parts without
PE connection
BENNING ST 720
≥ 2 MΩ
(protection class II),
≥ 0.25 MΩ
(protection class III),
≤ 0.5 mA
on conductive parts
without PE connection

≥ 1 MΩ
21