Contact Protection Measures - WIKA 821 Mode D'emploi

5. Commissioning, operation
Seal the cable entry with the appropriate approved cable glands.
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Cable gland design
Standard
Install the connection cables securely.
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5.3 Contact protection measures

Mechanical contacts must not exceed the specified electrical values for switching
current, switching voltage and switching power independent of each other, not
even for a short time only.
For capacitive or inductive loads we recommend one of the following protective
circuits:
Inductive load with DC voltage
With DC voltage the contact protection can be achieved via a free-wheeling di-
ode, connected in parallel to the load. The polarity of the diode must be arranged
so that it closes when the operating voltage is on.
Example:
Contact protec-
tion measure with
free-wheeling
diode
Operating instructions pressure gauges with switch contact models 821, 851 or 830 E
Only use
cable with a
diameter of
7 ... 13 mm
Contact
Instruments > 4 kg
Diode Load
Only use
cable with a
diameter of
5 ... 10 mm
15
EN