Enhancing Industrial Control Systems: The Importance of PLC Shielding and Grounding

Shielding and grounding are essential for protecting the Programmable Logic Controller (PLC) from unwanted electrical noise.

This noise can originate from a variety of sources, including:

  • Electromagnetic interference
  • Electrostatic Discharge (ESD)
  • Ground Loops

Electromagnetic Interference

EMI, which is generated by motors, transformers, drives, & other electrical equipment, can disturb the delicate signals within your PLC, resulting in inconsistent operation and malfunction.

Electrostatic Discharge (ESD)

Static energy generation & discharge can harm sensitive PLC components, resulting in data corruption and hardware failure.

Ground Loops

These occur when the system contains multiple grounding points at various potentials, resulting in undesired currents that may interfere with PLC signals.

Shielding & Grounding Procedures in PLC

Effective shielding & grounding procedures can greatly reduce the impact of electrical sounds on the PLC, assuring consistent operation and correct data processing.


Shielding includes enclosing your PLC and its wires in a conductive material, including metal conduit (or) grounded metal enclosures. This forms a barrier that filters (or) weaken incoming EMI & ESD, avoiding them from affecting the delicate electronics inside.

Here are some important points regarding PLC shielding.

  • Material selection: Select a material with the good conductivity & high shielding effectiveness, including aluminium, copper, or steel.
  • Continuity: Continuity is crucial. Ensure that all shielding components are properly connected & grounded to produce a continuous shield.
  • Cable considerations: Shielded cables must be utilized for signal & power connections to reduce noise ingress.


Grounding links all conductive elements in the system to a single reference point, typically the earth ground. This ensures that any noise-induced currents can dissipate safely without interfering with the PLC signals.

Here are some key components of PLC grounding:

  • Single-point Grounding: To avoid ground loops, that maintains a single grounding point across the system.
  • Grounding connections: Use the correct connectors and cables to provide a stable & low-impedance connections to the ground plane.
  • Grounding wires: Use grounding wires that are substantial enough to accommodate any potential fault current.

By correctly utilizing shielding and grounding procedures, we can establish an effective barrier against electrical noise and reduce its influence on the PLC system. For advanced equipment or conditions involving high noise levels, it is suggested to consult with competent electrical experts.

Implementing these best practices for PLC shielding & grounding can help to maintain a dependable and noise-free system, resulting in precise data processing & optimal performance for the industrial control applications.