Is your Home Office LAN fast enough? Does it need bonding?

Do S/FTP Cables Require Separate Bonding, or Does Network Equipment Handle It?

When installing S/FTP (Shielded Foiled Twisted Pair) cables, one of the key questions that arises is whether these cables require separate bonding and grounding or if the network equipment itself takes care of it. In this blog post, we’ll explore how S/FTP cabling works, when additional bonding might be necessary, and best practices for proper grounding.

If you wish to take full advantage of a modern broadband internet connection fibre to the home (FTTP/FTTH) you may wish to upgrade your LAN cabling to CAT6A to transmit more than 100 mbps around the home. ISPs tend to rely on WiFi connections to do this, but there are situations where a hard wired connection is a much better choice. CAT6A cable is usually S/FTP, but note you’ll need larger holes as it is about 9mm in diameter. Any patch cords along the network should also be S/FTP and rated at CAT6A. Lower grade patch cords will work, but compromise the shielding and lead to lower speeds.

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What Is S/FTP Cabling?

S/FTP cables are a type of shielded twisted pair cable designed to reduce electromagnetic interference (EMI) and improve signal integrity in environments where electrical noise is a concern. These cables have two layers of shielding:

1. Overall Shielding: A foil shield wraps around the entire cable.

2. Individual Pair Shielding: Each twisted pair inside the cable has its own foil shielding.

This dual-layer shielding makes S/FTP cables ideal for high-performance networks, particularly in electrically noisy or industrial environments.

However, for the shielding to function effectively, it must be properly grounded.

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Does Network Equipment Handle Grounding?

Modern network devices such as switches, routers, and patch panels often provide grounding for the shields in S/FTP cables. Here’s how it works:

• Shielded Connectors: S/FTP cables typically use shielded RJ45 connectors that make contact with the network equipment’s metal chassis.

• Equipment Grounding: If the switch, patch panel, or other network device is properly grounded (usually through its power connection or a direct earth connection), it can handle the grounding for the cable shields.

This built-in grounding ensures the shield does its job of mitigating EMI without requiring additional steps in most small-scale or standard installations.

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When Is Separate Bonding Required?

While modern network equipment can often handle grounding, there are scenarios where separate bonding becomes necessary:

1. Unreliable Equipment Grounding: If the network equipment does not provide sufficient grounding (e.g., the metal chassis is isolated or improperly grounded), the shield will not function correctly. In this case, a separate bond to the building’s electrical ground system is needed.

2. Large Installations: In large-scale structured cabling systems, proper bonding is crucial. Shielded patch panels, racks, and earth bars must be grounded to meet industry standards like TIA/EIA or ISO/IEC 11801.

3. High-EMI Environments: Industrial facilities, power plants, or data centers often have high levels of EMI. In these cases, additional grounding ensures the shielding remains effective.

4. Cross-Building Installations: When running S/FTP cables between buildings or across different grounding zones, you must bond the cable shields at each end while carefully avoiding ground loops.

5. Long Cable Runs: For long cable runs, improper grounding can introduce noise or signal issues, requiring a dedicated bonding solution.

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Best Practices for Bonding and Grounding S/FTP Cables

To ensure the shielding in S/FTP cables functions effectively, follow these best practices:

1. Use Shielded Components: Ensure all parts of your network—including patch panels, switches, and connectors—are shielded and compatible with S/FTP cables.

2. Verify Equipment Grounding: Check that network devices and racks are properly grounded to the building’s electrical ground system.

3. Avoid Ground Loops: When bonding cable shields at both ends, ensure there are no conflicting ground connections that could create a ground loop.

4. Follow Standards: Adhere to industry standards like ISO/IEC 11801 and ANSI/TIA-568 for grounding and bonding structured cabling systems.

5. Ground the Patch Panel: Use shielded patch panels and bond them to a common earth point in the rack or cabinet.

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Common Scenarios Explained

Let’s break it down further with two common scenarios:

Scenario 1: Small Office Network

In a small office with modern, properly grounded switches and patch panels, the network equipment typically handles shield grounding. No separate bonding is required as long as the devices are installed correctly.

Scenario 2: Industrial Facility or Data Center

In environments with significant EMI or long cable runs, additional grounding and bonding are necessary. Shielded patch panels, racks, and dedicated earth bars should be used to provide a reliable ground for the cable shields.

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Is Network Equipment Without a Grounded Power Cord an Issue

If network equipment uses a two-wire power cord, it is likely not grounded. Here’s why:

Two-Wire Power Cords: These cords only include a live and neutral wire, without an earth/ground wire. Devices using such power cords are typically double insulated, meaning they have extra insulation to protect against electrical faults. While this is safe for basic operation, it means the device chassis is not connected to earth ground.


Impact on Shielded Cables: Without a grounded chassis, the device cannot ground the shield of S/FTP cables. This can result in the shielding becoming ineffective, allowing EMI to interfere with network performance.

What to Do if Your Equipment Is Not Grounded

If your network equipment has a two-wire power cord:

Use Grounded Patch Panels: Ensure your patch panels or racks are properly grounded to provide a path for the cable shields.

Separate Bonding: Bond the shields of your S/FTP cables to the building’s electrical ground system at an appropriate location.

Verify Installation: Use a multimeter to confirm that shields are grounded where needed and that no stray voltages are present.

If you are operating in an environment with significant EMI or long cable runs, consider replacing ungrounded equipment with grounded alternatives.

Conclusion

In most cases, modern network equipment will handle the grounding of S/FTP cables if it is properly grounded itself. However, for larger installations, industrial environments, or when running cables across different grounding zones, separate bonding may be required to ensure the shielding performs effectively.

By following best practices and adhering to industry standards, you can ensure your S/FTP cabling system delivers optimal performance and avoids potential grounding issues.

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Key Takeaway: Always verify your network equipment’s grounding capabilities, and when in doubt, bond your S/FTP cabling to a dedicated ground to maintain signal integrity and reduce EMI.