Equipotential Bonding - Siemens SIMATIC ET 200AL System Manual

Equipotential bonding

Definition according to DIN VDE 0100
Equipotential bonding is an electrical connection which brings the bodies of electrical
equipment and external conductive parts to the same, or nearly the same, potential.
Equipotential bonding is divided into:
● Main equipotential bonding
● Additional local equipotential bonding
Both versions of equipotential bonding are of great importance not only for protection against
electric shock, but also for EMC.
Main equipotential bonding
Main equipotential bonding is required by DIN VDE 0100 Part 410 as a protective measure
and is mandatory, regardless of other measures for protection against direct and indirect
contact.
Additional local equipotential bonding
Additional local equipotential bonding is required if:
● Unfavorable grounding conditions exist between plant parts due to different conductivity
● Cables bridge a large distance
● Electrical energy is fed in from various power supplies (for example, in the case of
● Considerable electrical power is used (for example, welding robots, large drives)
Designing interference-free controllers
Function Manual, 06/2014, A5E03461486-AB
of the soil (for example, sandy or stony ground)
multiple substations)
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