Multi-Core Flexible Control Cables — YSLY vs YSLCY


YSLY and YSLCY

Multi-core flexible control cables are widely used in industrial systems to carry control and signal wiring between equipment, panels, and machines. If you have worked around control panels or automation lines, you have likely come across cable names like YY and CY. In specifications, these are often written as YSLY and YSLCY. 
 
These terms come from an earlier German naming system, used before European standards (HD 361 / HD 308) were harmonised. In that system, YSLY was developed in the 1960s as a flexible control cable for machinery and panel wiring, with YSLCY introduced later as the screened version.
 
Today, both naming conventions are still widely used — and they refer to the same cable family:

  • YSLY (YY) → Unscreened flexible control cable
  • YSLCY (CY) → Screened flexible control cable with copper braid

Understanding this helps bridge the gap between what is written in a datasheet and what is used on the ground. 

What are Control Cables?


Control cables are designed to transmit signals and low voltage control circuits, not to carry main electrical power. 
They are commonly used in:

  • Automation systems
  • Control panels
  • Manufacturing equipment
  • Instrumentation systems

Why Flexibility Matters

Unlike fixed power cables, control cables often need to:

  • Be routed through tight spaces
  • Bend around panels and equipment
  • Be installed and replaced easily

This is why they are made with fine stranded copper conductors, allowing them to flex without breaking.

YSLY vs YSLCY

Cable Construction

 

To understand how YSLCY and YSLY cables perform, it helps to look at how they are built.

Conductor (Core)

  • Carries the electrical signal.
  • Made of fine stranded copper (usually Class 5) for flexibility.

Insulation

  • Keeps signals separated.
  • Most commonly PVC (cost-effective for general use).
  • Can also be XLPE or specialised compounds for higher temperature needs.

Shield

  • Protects against electrical noise.
  • Made of tinned copper braid to reduce electromagnetic interference (EMI) and protect signal quality.

Outer Sheath

  • Protects from physical and environmental damage.
  • Typically PVC, providing resistance against abrasion, oil, and moisture.

Difference between YSLY and YSLCY

The main difference comes down to shielding.

Cable Feature

YY / YSLY

CY / YSLCY

Shielding

No shielding (unscreened) Tinned copper braid (screened)

EMI Protection

No Yes
Flexibility Flexible Flexible

Cost

Lower Higher

Typical Use

General purpose control Noisy electrical environments

When Should You Use YSLY or YSLCY?

 

In industrial environments, equipments such as motors, variable frequency drives (VFDs), and power cables generate electromagnetic noise. This noise can interfere with nearby control cables and affect signal reliability.

This leads to a practical rule of thumb:

Cable

YY / YSLY 

CY / YSLCY

Criteria

  • The environment is electrically clean   
  • There is minimal risk of interference   
  • Cost efficiency is a priority   

 

  • Motors, drives, or heavy electrical equipment nearby   
  • Signal accuracy and stability are important   
  • You need protection against electrical interference   

Typical Applications

  • Simple control wiring

  • Indoor panel connections

     

  • Automation lines

  • Factory equipment

  • Control panel with VFDs

Keystone Multi-Core Flexible Control Cables

 
At Keystone Cable, we supply both YSLY (YY) and YSLCY (CY) multi-core flexible control cables designed for industrial applications. The corresponding model codes are S05VV-F for YSLY (YY) and S05C4V-K for YSLCY (CY).


Our oil-resistant variants are also VDE certified, ensuring compliance with recognised factory standard cable requirements for industrial environments.

All cables undergo stringent testing, including tensile and elongation tests, to ensure consistent flexibility and mechanical durability in real-world operating conditions.

If you are unsure which cable suit your application, please reach out to us.

If you are interested in learning more about the solutions Keystone Cable can provide you, please contact us.

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