Shielded vs Unshielded Data Cable¶

Choose between shielded (STP/FTP) and unshielded (UTP) Ethernet cable for UK home installations. This guide covers EMI protection, grounding requirements, cost differences, and when shielded cable is necessary.

Understanding Cable Shielding Types¶

Ethernet cable shielding types: UTP (Unshielded Twisted Pair) - no shielding, relies on twisted pairs for interference rejection. FTP (Foiled Twisted Pair) - overall foil shield around all four pairs. STP (Shielded Twisted Pair) - each pair individually foil-shielded plus overall braid shield. SFTP (Shielded and Foiled Twisted Pair) - each pair shielded plus overall braid - maximum protection. UTP is standard for UK home installations and sufficient for 99% of residential applications. The twisted pair design cancels EMI without shielding. Shielded cable is needed in specific scenarios: running cables parallel to mains cables for more than 5 metres, near industrial equipment (motors, welders, transformers), in commercial environments with high EMI, external runs between buildings. The physics: shielding works by wrapping a conductive layer around the cable to intercept EMI. The shield must be grounded at both ends for STP (or one end for FTP) to drain induced currents to earth. Improperly grounded shielded cable acts as an antenna, making interference worse than UTP.

Grounding Requirements and Installation Best Practices¶

Shielded cable requires proper grounding to function correctly. Grounding components: shielded keystone jacks with metal housing (£4-£8 each), shielded patch panel with ground bar (£60-£100 for 24-port), shielded patch leads (£3-£5 each), ground connection from patch panel to building earth (6mm2 earth wire). Installation rules: the shield must be continuous from end to end. Connect the cable drain wire to the shielded keystone. Ensure all shielded components are electrically connected. Ground the patch panel to the building earth at one point only (star grounding). Do not create ground loops by grounding at multiple points. For FTP cable connect the shield at one end only (usually the patch panel end) to prevent ground loops. Testing shielded installations: use a shield continuity tester (£30-£60) to verify the shield is intact from end to end. A multimeter checks shield resistance - should be under 5 ohms end to end. Common mistakes: mixing shielded and unshielded components breaks the shield path entirely. A single unshielded keystone in a shielded installation negates all shielding. Cost comparison: shielded Cat6a installation costs 30-50% more than unshielded. For a 20-point new build installation: UTP £400-£600, STP £600-£900 in materials alone. Professional installation adds £400-£800 extra for shielded grounding.

Specifications and Comparison¶

Shielding Type	EMI Protection	Grounding Required	Cost vs UTP	Best For
UTP (Unshielded)	Standard	No	1x baseline	UK home installations
FTP (Overall Foil)	Good	One end only	1.2x	Near mains cables
STP (Individual Shield)	Very Good	Both ends	1.5x	Industrial, commercial
SFTP (Dual Shield)	Maximum	Both ends	2x	High-EMI environments

FAQ¶


: . For more information see our What Is the Difference Between UTP and STP Cable.

Last updated: 2026-05-31.

External Resources¶

For further information consult authority guidelines at the Which?.