Answer:

Grounding consists in connecting to a protective earth point with a conductive wire a metal structure that may be accidentally brought into contact with the electrical power grid caused by an insulation issue.
The grounding allows leakage currents to flow safely, combined with an automatic disconnection device (differential circuit breaker), it will switch off the electrical installation.

Why grounding ?
For user’s safety !

Example:

Take a SENSY electronics that is not connected to a grounded power outlet and a rodent that damaged the outer sheath of the power cable from this unit and its wires touch the housing
Touching the enclosure while being on a conductive floor will cause electric shock
Grounding combined with differential circuit breaker prevents such an incident.
The current flows directly into the ground and the power supply is automatically shut off.
No more electrocution, no more danger !

All SENSY electronics and sensors must be grounded !!!

Grounding is only effective if it is associated with a differential circuit breaker.

A good protective earth connection must have an electrical resistance calculate on the sensitivity of the differential device of the installation. The maximum resistance of the protective earth connection must be 100 ohms.

Rules to follow:

• Protective earth connection must be away from any deposit or infiltration that may corrode it (e. g. chemicals)
• Grounding connection should never be submerged by water.
• Water, gas or heating pipes and metal cable sheaths must not be used as protective earth.