O P E R AT I N G I N S T R U C T I O N S | Bulkscan®
8014829/ZV98/2018-05-07| S I C K
Subject to change without notice
4 5
ELECTRICAL INSTALLATION
Control system
Grounding point 1
Grounding point 2
Metal housing
Shielded electrical cable
Ground potential difference
Bulkscan®
Closed current loop with
equalizing currents via cable
shield
Power supply
Fig. 26: Currents in the cable shields due to differences in ground potential
Due to insufficient ground potential equalization, voltage differences arise between
the grounding points 1 and 2. The current loop closes via the shielded cables and the
housings.
Risk of injury and damage caused by electrical current!
Potential equalization currents between the Bulkscan® and the peripheral devices can
have the following effects:
• Dangerous voltages on the metal housing, e.g., of the Bulkscan®.
• Incorrect function or irreparable damage to the devices.
•
Damage/irreparable damage of the cable shield due to heating and cable fires.
Where local conditions are unfavorable and thus do not meet conditions for a safe
grounding method (same ground potential at all grounding points), take measures as
described below.
Remedial measures
The most common solution for preventing potential equalization currents on cable
shields is to ensure low-impedance and current carrying equipotential bonding. If this is
not possible, we suggest the following two solutions.
We expressly advise against opening up the cable shields. This would mean that the
EMC limit values can no longer be complied with and that the safe operation of the
device data interfaces can no longer be guaranteed.
Note
