Guidelines for Installing an Island Grounding System

Guidelines for Installing an Island Grounding System

Definition: Island grounding system In an industrial environment the electrical equipment is usually grouped into specific areas or islands. A grounding system does not necessarily have to cover the entire building. Instead, the islands grouping together electronic equipment should be defined. When electronic equipment is grouped into an area that is larger than approximately ten square meters, a cage measuring 3 m2 to 5 m2 should be created by interconnecting the different grounding structures and enclosures. A grounding cell is created by daisy chaining the grounding points. This can be cabinets, machine chassis and metallic cable ducts:

NOTE: Sensor and actuator cables outside of these islands must be shielded with great care!

Example of daisy chaining When equipment is grouped into several enclosures side by side, they are bolted together and thus make up an island. Two or more cabinets or machine chassis can be connected to an island by daisy chaining their grounding points. Ground connections for cabinets and constructive components:

Guidelines and recommendations for island grounding systems Recommendations for creating a grounding cell:  An island may not be larger than 3 ... 5 m2 .  "Conductive" false floors can be used to create an effective island grounding system. For reasons of practicality only one of three supports needs to be connected. This gives you a cell of 1.80 m2 .  The connections can be made using copper rod, short, fat bolts or with grounding strips.  Where possible a direct positive fit contact should be made, for example, for the connection of metal cable ducts.  When two chassis or cabinets are installed side by side, they should be connected directly to each other at at least two points, i.e. above and below.  Ensure that paint or any other coating does not affect the electrical contact. The use of lock washers is recommended.  The cross-section of straps is not relevant since only their lenght is important. The grounding connections must not exceed 50 cm.