ISO/IEC 11801

UTP, FTP or S/FTP - which cable shielding fits?

Whether UTP, FTP or S/FTP, the shielding determines noise immunity and transmission quality. This guide sorts the shielding types by EMC environment, explains the grounding concept per ISO/IEC 11801 and helps you pick the right cable class.

5 minStand: 2026-07Geprüft: Technical editors

View data cables

3 types

UTP, FTP, S/FTP

10 Gbit/s

Cat.6A over 100 m

1 point

single-ended grounding

40 Gbit/s

Cat.8 over 30 m

Inhalt

Shielding types
Choose by environment
Grounding concept
Cable classes
Frequently asked questions

What do UTP, FTP and S/FTP mean?

The abbreviations describe how a data cable is protected against electromagnetic interference. The structure follows the pattern X/YZZ: the first letter denotes the overall shield, the part after the slash the shielding of the individual pairs. This lets you read off every construction unambiguously.

U/UTP: no overall shield, no pair shield - the classic unshielded cable.
F/UTP (FTP for short): overall foil shield, unshielded pairs.
U/FTP: each pair wrapped in foil, no overall shield.
S/FTP: braided overall shield plus foil around each pair - highest noise immunity.
SF/UTP: overall braid and foil shield, unshielded pairs.

The letter before the slash refers to the cable-jacket shield: U = unshielded, F = foil, S = braid, SF = braid plus foil. After the slash, TP describes the unshielded twisted pair and FTP the foil-wrapped pair.

Connectivity

Matching plugs, patch panels and keystone modules for every cable class.

Read the guide

Which shielding suits which EMC environment?

The choice depends on the electromagnetic load at the installation site. In a quiet office UTP is often enough, in a production hall with variable-frequency drives and motors S/FTP is the safe choice. Decisive factors are nearby interference sources, power cables run in parallel and the required data rate.

Where data cables run parallel to power lines, keep at least 20 cm of separation or use separate trays. Shielded cables reduce the required distance, but they cannot fully replace physical separation.

A shielded system only works with continuous shield continuity: cable, plugs, jacks and patch panel must all meet the shielding class together. A single unshielded module in the link largely cancels the advantage of the S/FTP cable.

How is the shield grounded correctly?

A shield only works if it is properly bonded to the equipotential system. Per ISO/IEC 11801 and DIN EN 50174 the shield is terminated at the distributor earthing bars. What matters is a clean, large-area contact rather than a long drain wire.

Single-ended grounding: avoids ground loops, recommended where potential differences may exist.
Double-ended grounding: best shield effect against high-frequency interference, requires a sound equipotential bond.
Contact the shield all around (360 degrees), not just via a thin pigtail wire.
Bond all components of the link to the same equipotential system.

In structured building cabling grounding is usually double-ended, because a code-compliant equipotential bond is assumed. If equal earth potential between two buildings is in doubt, single-ended grounding or fibre optic is the safe alternative.

Equipotential bonding

Earthing bars and shield clamps for a code-compliant termination.

Read the guide

Which cable class do I need?

The category (Cat.) sets the bandwidth and thus the maximum data rate. For new installations Cat.6A is the standard, because it reliably carries 10 Gbit/s over the full 100 m run. Higher classes are reserved for data centres and short links.

From Cat.7 upward cable is only available in shielded form (at least S/FTP), because the required frequencies cannot be reached interference-free without a shield. Cat.8 is designed for short data-centre links and needs consistently shielded connectors.

Plan the class according to the expected service life of the cabling, not today's need. A Cat.6A S/FTP system offers reserves for upcoming 10 Gbit/s applications at a manageable extra cost.

Frequently asked questions

Is S/FTP always better than UTP?

Only where interference sources are present or high data rates are required. In a low-noise office UTP meets the requirements more cheaply and is easier to install. In industry and data centres S/FTP is clearly superior.

Does a shielded cable have to be grounded?

Yes, otherwise the shield does not work and can even act as an antenna, coupling in interference. The shield must be bonded to the equipotential system via plug and patch panel, contacted all around rather than through a thin wire.

Single-ended or double-ended grounding?

In structured cabling with a clean equipotential bond grounding is usually double-ended, giving the best HF protection. Where potential differences may exist, single-ended grounding prevents ground loops.

Which cable class for Gigabit Ethernet?

Cat.5e is enough for 1 Gbit/s over 100 m. For 10 Gbit/s over the full run Cat.6A is required. For new installations Cat.6A is recommended straight away as a future-proof base.

Looking for the right data cable?

We supply UTP, FTP and S/FTP cables from Cat.5e to Cat.8 together with shielded connectivity - matched to your EMC environment and grounding concept.

View data cables Request advice

Standards-compliant

Cables and components per ISO/IEC 11801 and DIN EN 50174.

Grounding included

Shield clamps and earthing accessories for a clean equipotential bond.

Fully shielded

Plugs and panels matched to the cable's shielding class.

Expert advice

Our specialists help you choose by EMC environment.