Grounding systems for expanded systems

We differentiate between a main grounding system that incorporates the entire plant and the local equipotential bonding for expanded systems:

  • Main system grounding system: Grounding system that incorporates the entire building

  • Local grounding system: Grounding system on the local level (device, machine, cabinet)

Guidelines for a building grounding system

EMC guidelines must be followed for the main grounding system in an expanded system within a building:

  • Each floor must have an earth plane as well as a surrounding grounding strip.

    This includes the following: welded, steel mats in the concrete bed, hollow floors with copper wire grids etc.

  • The distance between earth conductors must be greater than the following values:

    • Production hall: 3 ... 5 m

    • Areas with computers and sensitive measuring devices: < 2 m

  • All metallic structures within a building should be connected to the network.

    • Metallic framework

    • Concrete reinforcements welded together

    • Metal piping

    • Cable ducts

    • Conveyor belts

    • Metal door frames

    • Grids

    • ...

NOTE: Earth cables may not be longer than 10/(frequency in MHz). Earth cables that are too long cause undefined potentials in the system, unavoidably lead to potential differences between devices and allow undesired currents.

Example: Earth plane in a building

The following illustration shows an example of EMC compatible installation of a grounding system in an industrial building