By Eileen Harvey
One of the most widely adopted communication standards in industrial environments is PROFINET, a real-time Industrial Ethernet protocol designed for reliability and speed. While controllers, sensors and devices play a critical role, the true backbone of this ecosystem lies in cabling. Choosing the right PROFINET cable can mean the difference between uninterrupted production and costly downtime. In this guide, we’ll explore everything you need to know about PROFINET cables, from their types and categories to construction, shielding, applications, installation practices and standards.
What Are PROFINET Cables?
At its core, a PROFINET cable is an Ethernet cable that has been engineered for industrial use. Unlike conventional office Ethernet cables, PROFINET cables are ruggedized to withstand heat, chemicals, vibration and moisture. They are shielded to resist electromagnetic interference (EMI) caused by motors, drives and welding equipment. And they are standardized by PROFINET International (PI) and IEC, ensuring compatibility across devices and systems.
Visually, PROFINET cables are often green for easy identification, though variations exist depending on the application.
While many PROFINET cables support 100 Mbps Fast Ethernet, newer versions also support Gigabit speeds (Cat6/6a/7) for future-proofing industrial networks.
Standards and Compliance
The effectiveness of a cable’s shielding depends heavily on its compliance with established industry standards that ensure consistent performance and reliability. ISO/IEC 11801 defines the global framework for structured cabling systems, while EN 50173 serves as the European counterpart. In the United States, TIA/EIA-568 outlines essential guidelines for network cabling installation and performance. Additionally, the PROFINET cabling guidelines specify requirements unique to industrial Ethernet environments. Meeting these standards requires proper termination and grounding practices, as poor grounding can completely undermine the benefits of shielding and leave systems vulnerable to EMI.
To maintain optimal performance, shield continuity must be preserved throughout the entire cable length. The shielding material should never be cut during termination, since any break can introduce weak points where EMI can penetrate. Using shielded connectors—such as RJ45 or M12 industrial types—helps maintain full coverage and consistent electrical performance. Installers should avoid tight bends that may crack foil or loosen braided shielding, and they should keep at least 20 centimeters of separation between shielded network cables and nearby power lines to minimize electrical noise. After installation, cables should be thoroughly tested with Fluke or equivalent certification tools to confirm signal integrity, shielding effectiveness, and proper continuity.
When selecting the right shielding type, foil shielding is the most cost-effective option for light automation tasks or stationary setups where EMI is minimal. Braid shielding is better suited for dynamic systems that experience frequent movement, vibration, or mechanical stress, offering enhanced durability and grounding performance. Combination shielding is ideal for harsh industrial environments or facilities anticipating future expansion, as it delivers robust protection and long-term scalability. For Industry 4.0 and other advanced automation systems, Cat6 or Cat7 cables with SF/FTP shielding provide the highest level of EMI resistance and ensure reliable data transmission across complex industrial networks.
Cable Categories: Cat5e, Cat6, Cat7
Since PROFINET is Ethernet-based, it follows common cabling categories. Cat5e supports up to 100 Mbps and is still widely used for PROFINET IO. Cat6/6a supports up to 1 to 10 Gbps, ideal for high-speed data and future-proofing. Cat7 offers even greater shielding, making it highly resistant to EMI.
If you are building a new system or upgrading, consider Cat6 or Cat7 PROFINET cables. Even if your devices only run at 100 Mbps, these higher categories ensure your network can scale.
Construction of PROFINET Cables
A PROFINET cable is far more sophisticated than a simple length of copper wrapped in plastic. Each component is precisely engineered to deliver the durability, flexibility, and performance required in industrial environments.
The conductor forms the core of the cable’s functionality, with solid copper used in fixed installations classified as Type A, and stranded copper employed in flexible or high-motion applications such as Types B, C, and R. This distinction ensures that the conductor type aligns with the mechanical demands of the installation, balancing rigidity and flexibility as needed.
The insulation and jacket materials play an equally important role in protecting the cable and ensuring longevity. PVC offers a cost-effective option with basic resistance to wear and environmental factors, making it suitable for standard conditions. PUR provides enhanced protection against oils and chemicals, which is essential for industrial facilities where exposure to such substances is common. For applications involving continuous movement, such as drag chains or robotics, TPE or TPU jackets deliver exceptional flexibility and durability, preventing cracking and mechanical fatigue even under repetitive stress.
Shielding is another critical element of PROFINET cable design. Foil shielding, or FTP, safeguards against high-frequency electromagnetic interference, while braided shielding, or STP, provides robust defense against low-frequency interference and mechanical strain. Many PROFINET cables combine these two types of shielding to achieve maximum EMI protection, ensuring reliable data transmission even in electrically noisy environments.
Color coding provides a simple visual cue for identifying cable types and functions. Green typically denotes standard PROFINET copper cables, while yellow or orange identifies fiber-optic versions used for extended distances or applications that demand immunity to electromagnetic interference. Each of these engineered layers—conductor, insulation, jacket, shielding, and color coding—works together to meet the stringent performance requirements of modern industrial networks.
Shielding and Noise Protection
Industrial floors are filled with potential sources of interference—welding machines, motors and inverters. Without shielding, data packets can be lost, causing latency issues, device communication errors and unexpected downtime.
As a best practice, always choose shielded PROFINET cables (S/FTP or SF/UTP), even in seemingly low-noise environments. Shielding ensures consistent communication.
Applications of PROFINET Cables
PROFINET cables are everywhere in automation. In factory automation they connect PLCs, drives and sensors. In motion control and robotics, Type C and Type R cables provide flexibility for moving parts. In process industries, they withstand harsh conditions like oil, dust and moisture. In building automation, they help integrate HVAC, lighting and access control. In control cabinets, Type A cables are cost-effective for static installations.
PROFINET supports not only data exchange but also real-time motion control—making cable quality critical for synchronized operations.
Installation Guidelines
Even the best cable can fail if poorly installed. Follow these practices:
- Maintain Bending Radius: Each cable type has a minimum bending radius (e.g., 10× cable diameter for fixed, 15× for moving).
- Avoid Parallel Routing with Power Cables: Keep at least 20 cm separation to reduce EMI.
- Grounding and Shielding: Proper grounding of the shielding is vital for EMI protection.
- Use Rugged Connectors: Use RJ45 (IP20) for indoor cabinets, M12 (IP65/67) for harsh industrial floors.
- Testing and Certification: After installation, test continuity, shielding and bandwidth compliance.
Standards and Compliance
PROFINET cables follow strict international standards to guarantee performance. IEC 61156 specifies transmission performance for twisted pair cables. IEC 61918 contains installation rules for automation networks. IEC 61784-5-3 includes PROFINET-specific cabling profiles. PROFINET International (PI) provides cabling and interconnection guidelines.
Using certified cables ensures interoperability and long-term reliability.
Tips and Recommendations
Let’s consider four tips. First, always plan for future scalability—choose Cat6 or Cat7 when possible. Second, use Type C or Type R cables in robotics and moving applications. Third, keep spare cables in inventory to avoid downtime. And fourth, don’t overlook fiber-optic PROFINET cables for long-distance and EMI-heavy zones.
Helpful Facts
- PROFINET cables can extend 100 meters per copper segment, but fiber optics allow distances of several kilometers.
- Even though Gigabit PROFINET is supported, most real-time control applications still use 100 Mbps—speed isn’t the limitation, determinism is.
- Some PROFINET cables can withstand over 10 million bending cycles, proving their durability in drag chain applications.
PROFINET cables may look like regular Ethernet, but their construction, shielding and compliance make them uniquely capable of handling industrial demands. By selecting the correct type (A, B, C or R), category (Cat5e, 6, 7) and installation practices, businesses can ensure reliable, interference-free communication.
In the world of automation, downtime is costly. Investing in the right PROFINET cable isn’t just a technical choice, it’s a strategic one for performance, efficiency and long-term reliability.
Explore the full range of TKD Kabel through L-com. We’ll fill your orders fast, with same-day shipping on all qualified, in stock, online orders received Monday through Friday before 5 p.m. EST. For TKD-related inquiries, connect with our U.S-based TKD expert Eileen Harvey at eharvey@infiniteelectronics.com.
