One of the most debated decisions in structured cabling is whether to use shielded or unshielded cable. The wrong choice can mean unnecessary cost, grounding headaches, or a network that underperforms in a noisy environment. Here's how to make the right call.
The Core Difference
Unshielded Twisted Pair (UTP) cable relies entirely on the twist rate of each pair to cancel electromagnetic interference (EMI). Shielded cable adds a metallic foil or braid layer — around individual pairs, the whole bundle, or both — to block external interference before it reaches the conductors.
Shielding Nomenclature Explained
The IEC 61156 standard uses a two-part code: XX/YTP, where XX describes the overall shield and Y describes the pair shield.
| Code | Overall shield | Pair shield | Common name |
|---|---|---|---|
| U/UTP | None | None | UTP |
| F/UTP | Foil | None | FTP / SFTP |
| S/FTP | Braid | Foil per pair | SFTP / SSTP |
| SF/FTP | Braid + foil | Foil per pair | SFTP (maximum) |
When to Use UTP
UTP is the right choice for the majority of commercial and residential installations. It's lighter, more flexible, easier to terminate, and less expensive. Because there's no shield to ground, you avoid the risk of a "ground loop" — a common problem with improperly grounded shielded systems that can actually introduce more noise than it removes.
Use UTP when:
- Office, retail, or residential environments with standard electrical infrastructure
- Runs are away from high-voltage power conduits (maintain at least 200 mm separation)
- Budget and installation speed are priorities
- Termination will be done by a mixed-skill team
When to Use Shielded (SFTP/FTP) Cable
Shielding earns its cost in environments with significant EMI sources or where data integrity is critical. The shield must be properly grounded at both ends — a single-ended ground is worse than no shield at all.
Use shielded cable when:
- Runs pass near or parallel to power cables, motors, HVAC equipment, or fluorescent lighting
- Industrial or manufacturing environments with heavy machinery
- Healthcare facilities with MRI or imaging equipment nearby
- Dense Wi-Fi 6/6E deployments where access points generate significant RF
- Data centres requiring 10G+ over CAT6A where alien crosstalk (AXT) is a concern
- Outdoor or semi-outdoor runs (use outdoor-rated shielded cable)
The Grounding Requirement — Don't Skip This
A shielded cable system is only as good as its grounding. Every shielded patch panel, keystone jack, and cable must be bonded to a common ground. If you can't guarantee a proper ground at both ends of every run, UTP will give you better real-world performance. This is the most common mistake in shielded installations.
Cost and Installation Considerations
Shielded cable typically costs 20–40% more than equivalent UTP. Factor in shielded keystone jacks, shielded patch panels, and the additional labour time for grounding, and the total installed cost difference is significant. For most projects, that budget is better spent on higher-quality UTP and proper cable management.
Summary: Quick Decision Guide
| Environment | Recommendation |
|---|---|
| Standard office / home | UTP (CAT6 or CAT6A) |
| Near power conduits or machinery | F/UTP or S/FTP |
| Industrial / manufacturing | S/FTP |
| Data centre (10G+) | CAT6A U/UTP or F/UTP |
| Outdoor / semi-outdoor | Shielded, outdoor-rated |
Shop Shielded and Unshielded Network Cables
Browse our full range of UTP and SFTP cables in the Network Cable collection. Not sure which spec is right for your site? Contact our team — we're happy to review your floor plan and recommend the right cable type for each zone.