Single Cores

In our single cores product group you will find harmonised and certified, halogen-free and shielded single cores for optimum EMC protection. Single cores are not sheathed cables, but rather individual, insulated cores without any further sheathing. The LAPP single cores are suitable for a wide range of applications such as wiring in control cabinets and the wiring of electrical assemblies and distribution panels.

What are single cores?

Single core refers to just a singular core, i.e. a plastic-insulated conductor without an outer sheath. Single cores are considered important components for wiring electronic assemblies in machines, devices and control cabinets. Single cores are also known as core lines, installation wires, bell wires, hookup wires, control wires or wiring lines.

Incidentally: one-core cables, one-core lines, single-core lines or single-core cables are all sheathed and therefore do not count as single cores.

In this guide, you will find out how the LAPP single cores differ, where they are used and which key questions are frequently asked.

You can find special cold-resistant and heat-resistant single cores for expanded ambient temperatures (-195°C to +700°C) under “Temperature-resistant cables”.

→ Switch to ÖLFLEX® HEAT


Why don't single cores actually need a sheath?

The outer sheath of a cable or line is a closed wrapping which protects the components underneath from being damaged or from any other external influences. Damage can be caused by excessive mechanical loads such as abrasion, shock, pressure or bending, or by significant chemical influences such as acids, alkalis, or oils. Thermal influences such as cold and heat, as well as physical influences such as UV radiation, also mustn't be allowed to have a negative effect on the electrical conductivity of cables.

Single cores that are fixed in protected environments and are no longer moved afterwards are not normally exposed to these influences. As a result, they can also cope without a space-consuming outer sheath.

Where are single cores used?

Single cores are typically used for electrical installations in buildings and industrial plants. They are used as supply and discharge lines for control cabinets, to wire circuits inside machines and to connect lights and signalling systems.

If compliance with fire protection requirements is a key focus during cabling, halogen-free materials should be chosen that emit as few toxic fumes as possible in the event of a fire. If the cabling is carried out outside of Europe, attention must be paid to the corresponding product certification for the application area (e.g. UL, CSA).

Most single cores must not be used outside of a closed system such as a control cabinet or cable duct without additional protection (e.g. an empty pipe or protective cable conduit). They are also suitable for fixed installation on or under plaster. Green-yellow single cores may be installed directly on cable trays, in channels and troughs, but only as a potential equalisation lines with a protective conductor function.


Looking for single core cables that can be moved in a highly flexible manner?

→ Switch to highly flexible single core cables


What are the differences between single cores?

The LAPP single cores are distinguished by

  • different core insulation materials,
  • the permissible temperature range,
  • certifications for different regions,
  • their permissible nominal voltage as well as
  • their packaging type.

A few single cores are also shielded (LiYCY and Li2YCY).

Core insulation

The most commonly used insulating material for single cores is PVC. More resistant insulation types made of polyolefin, silicone or glass fibre, on the other hand, are used when the single cores must withstand higher temperature ranges.

Single cores are often required with an insulation compound that does not contain halogens (halogen-free single cores). This is because halogens release corrosive gases in the event of a fire. Halogenated single cores made of PVC, for example, are not permitted in public areas and wherever a lot of people gather.

Halogen-free cables- How, what, when and why?

Temperature ranges

The specified temperature range always applies in the case of fixed installation of the single cores. The permissible temperature range may vary depending on the certification.

Temperature ranges, for example of the MULTI-STANDARD SC 2.1:

HAR / IEC: -40°C to +70°C
UL (AWM): to +105°C
UL (MTW): to +90°C
CSA (TEW): to +105°C


The HAR marking on cables and lines is of particular importance for goods transport between European countries. This is because wherever national standards are not sufficient, harmonised markings are used throughout Europe. The aim of this is to distribute standardised products based on standardised designs, assemblies and test criteria. The <HAR> testing mark stands for tested safety and quality and confirms that the single core is not only based on the type standard specified in the harmonisation document (HD), but also corresponds 100% technically to the type standard and is type-certified accordingly.

To build single cores in North America, you must look out for UL or CSA certification. Depending on the area of application, the single core should include a UL Recognition Mark or a UL Listing Mark, for example.


For example, the UL (MTW) seal according to the UL standard 1063 states that the single cores are suitable as machine tool wires.

The CSA (TEW) seal according to CSA C22.2 No. 127 states that the single core is suitable as thermoplastic equipment wire.

The advantages of multi-standard single cores are clear:

              - reduced procurement effort

              - less storage (space and costs)

              - more efficient spare part management

              - reduced documentation costs

Nominal voltage

In Europe, control cabinet single cores are designed for the voltage classes 300/500 V or 450/750 V. Depending on the single core certification, the nominal voltage permitted for North America may deviate greatly from this, as different voltage classes may be required for this area of application and depend on the corresponding standard.

Information on the nominal voltage using the example of MULTI-STANDARD SC 2.1:

HAR / IEC: U0/U: 450/750 V

UL (AWM): U: 600 V

UL (MTW): U: 600 V

CSA (TEW): U: 600 V

In the case of harmonised types with HAR markings, the permissible nominal voltage is easily legible:

What is the difference between a H05V-K and a H07V-K?

H05 = 300/500 V

H07 = 450/750 V

Packaging type

The LAPP single cores are available as a ring (100 m or in excess lengths for our TRONIC modules), on coils (100 m, 150 m, 250 m) or, but only up to max. 6 mm2, also in a large cardboard box (type K up to 3000 m, type E up to 9000 m).

Type abbreviations

The essential properties of a single core can be found via the type abbreviation. We will provide you with a short decryption aid using the example of H05V-K 1X0.5 YE:

H = Basic type (harmonised type)

05 = Nominal voltage (300/500 V)

V = Insulating material (PVC)

K = Conductor type (fine-wire for fixed installation)

1 = Number of cores (1)

0.5 = Conductor cross-section (0.5 mm2)

YE = Core insulation colour (yellow)

Core insulation colours

The common core insulation colours for single cores are grey, white, yellow, orange, red, violet, blue, green, brown, black, green-yellow, dark blue. Some single cores are marked with a two-colour spiral that allows the cable to be identified quickly in a small space.

Conductor cross-section

Control cabinet single cores are typically made from a fine-wire, tin-plated copper strand (according to VDE 0295 class 5). It is bendable and therefore easy to install. Harmonised single cores are available in conductor cross-sections from 0.5 mm2 to 240 mm2; the LiY single core is available from 0.14 mm2.


In EMC-sensitive environments where electromagnetic interference on other components must be avoided, it is sometimes necessary to shield single cores as well. This includes either copper stranded shielding or a copper wire wrapping.

Shielded cables- Why is EMC protection important?

suitable accessories below

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