By TEBAOFLEX Jyen. Originally published on January 9, 2026.
YY, CY and SY are common control-cable descriptions, but they do not by themselves establish a standardized construction or installation approval. LiYCY and LiHCH descriptions likewise need an actual manufacturer datasheet. Compare the complete cable specification and the circuit requirements, not just the letters or visible braid.
What the common descriptions usually distinguish
- YY: commonly an unscreened control construction; verify insulation, sheath and rated duty.
- CY: commonly a copper-braided screened control construction; verify the documented EMC properties and termination.
- SY: commonly a steel-braided control construction; do not assume it provides the protection of an armoured power cable.
- LiYCY: commonly a screened signal construction with PVC materials; check whether the version has twisted pairs.
- LiHCH: commonly a screened halogen-free signal construction; verify the stated smoke and halogen tests and electrical parameters.
The IET notes that SY/CY/YY names are not, by themselves, a recognized national, European or international cable standard. Its installation-design guidance also warns that the steel or copper braid should not automatically be treated as mechanical protection or as a compliant protective conductor. Installation acceptance requires a documented design assessment.
Screening and mechanical protection are different
A copper screen can provide a useful high-frequency interference path when properly terminated, but shielding depends on geometry, material, frequency and installation. A steel braid cannot be substituted for a specified EMC screen solely because both look metallic. Conversely, a copper braid does not make a cable crush-proof.
Request transfer-impedance or shielding data with frequency and measurement method. Near-end crosstalk describes coupling between circuits and is not the same quantity as shielding attenuation against external fields. A single dB ranking that mixes these measurements is not a valid cable comparison.
Match the signal, not just the core count
Twisting a signal with its return can reduce interference in a balanced circuit. It does not cancel every disturbance or guarantee a particular data rate. For RS-485, CAN or an encoder link, verify the interface-specific impedance, capacitance, attenuation, topology and termination requirements.
An overall shield does not necessarily control crosstalk between internal circuits. Pairing, individual screens and separation may be required. Do not treat ordinary multicore LiYCY as automatically equivalent to a protocol-qualified twisted-pair cable.
LSZH is a set of specified properties
A halogen-free material declaration, a smoke test and a flame-spread test address different properties. LSZH does not mean that combustion is harmless or smoke-free. Request the test methods, limits and evidence applicable to the finished construction, and check any building, transport or marine requirements separately.
Bonding follows the equipment and system design
One-end and both-end screen connections have different implications for low-frequency circulating currents and high-frequency EMC. There is no universal rule based only on whether the signal is analogue or digital. Follow the equipment instructions and the approved grounding design, including equipotential bonding where required.
Keep EMC connections short and suitable for their frequency range. Do not use an arbitrary 16 mm² bonding conductor or treat a screen as protective earth without a fault-current and installation assessment. Never disconnect a protective conductor to troubleshoot noise.
Specify the operating environment
- Fixed installation, occasional movement or continuous flexing, with the relevant bend radius.
- Outdoor exposure, UV, oil, water, temperature and required mechanical protection.
- Conductor identification, terminal compatibility and required protective conductors.
- Documented electrical and fire properties, approvals where applicable and traceable acceptance records.
No unsupported factory measurements or universal screening, crush or service-life figures are claimed here. Use the exact offered datasheet and system requirements to decide suitability.
Sources and application documentation
Discuss the application
Send the application duty, installation drawing and required acceptance criteria to TEBAOFLEX. WhatsApp: +86 185 9591 3361. Request the applicable product documentation before ordering.