Introduction: MKESH and MKESHV — Two Versions of Instrumentation Cable
Shielded instrumentation cables of the MKESH and MKESHV types are used for fixed inter-device and intra-device connection in control, alarm and data transmission circuits. Both types contain stranded copper conductors with a cross‑section from 0.35 to 1.5 mm², polyethylene insulated and laid in a common screen of copper braid. The difference between them is the presence of an outer PVC sheath on MKESHV, whereas MKESH is supplied without it: the screen remains exposed.
The absence or presence of a sheath determines the mechanical protection, resistance to moisture and permissible installation methods. Both types remain compliant with GOST 10348‑80 and are used in equipment where noise immunity is important. The range includes conductor combinations from 2 to 10 cores, including twisted pairs — 2×2×0.75, 4×2×1 and others. Detailed information about instrumentation cables and their characteristics is gathered in the review details about MKESH.
Comparative Table of Characteristics
| Parameter | MKESH | MKESHV |
| Design | Copper conductors with PE insulation, overall screen of copper braid, without outer sheath | Copper conductors with PE insulation, overall screen, over which a PVC sheath |
| Outer diameter (for 3×0.75) | ~6.2 mm | ~7.0 mm |
| Mass (10×0.5) | ~190 kg/km | ~230 kg/km |
| Working voltage | Up to 500 V AC with a frequency of up to 400 Hz or up to 750 V DC | Identical |
| Insulation resistance | Not less than 100 MΩ·km | Not less than 100 MΩ·km |
| Temperature range | –50…+70 °C | –40…+70 °C (PVC limits frost resistance) |
| Protection against mechanical impacts | Minimal; the screen is subject to abrasion and damage | Good; the PVC sheath protects the screen and conductors |
| Resistance to moisture and chemical agents | Low; moisture penetrates under the braid | High; the sheath seals the cable |
| Fire‑safe versions | ng, LS possible (rare) | ng, ng‑LS, FRLS — a wide choice |
| Flexibility | High, bending radius 5 diameters | Medium, bending radius 7 diameters due to the rigidity of the sheath |
| Cost | Lower, due to the absence of a sheath | 10–20 % higher |
| Typical areas of application | Inside devices, cabinets, sealed volumes | Inter‑unit connections, installation in cable ducts, open routing |
Design Differences and Shielding
The basis of both types is a multi‑stranded copper core with polyethylene conductor insulation. The individual conductors are twisted into a core or into pairs, after which an overall screen of copper braid with a density of at least 65 % is applied. The screen suppresses external electromagnetic interference and prevents the radiation of the signal outwards. For MKESH, the design ends here — the braid is the outer layer. For MKESHV, a sheath of PVC compound is extruded over the screen, which can be grey, white or black. This detail radically changes the area of use of the cable.
The exposed screen of MKESH can easily be damaged during pulling, it is subject to oxidation in a humid environment, but it allows earthing at any point along the length by simply soldering a wire to the braid. MKESHV requires removal of the sheath to access the screen, but it possesses an integrity of the covering that protects both the screen and the conductors from dust and splashes. More details about the designs and application of MKESHV are written in the material about MKESHV cable.
Protective Sheath and Operating Conditions
The presence of a PVC sheath on MKESHV solves several tasks at once. Firstly, the sheath mechanically protects the screen from abrasion during vibration and contact with the sharp edges of mounting panels. Secondly, it seals the internal cavity of the cable, preventing capillary penetration of moisture along the conductors. This is especially important for inter‑unit connections in unheated cabinets or outdoor installations. Thirdly, PVC can be supplied in ng‑LS and FRLS versions that meet fire safety requirements in public buildings. MKESH without a sheath cannot provide standardised smoke emission, since the exposed screen and insulation do not form a single fire‑resistant barrier.
On the other hand, the absence of a sheath on MKESH gives an advantage in dimensions and flexibility. Inside sealed enclosures, where there is no risk of mechanical impact and humidity, a sheath is not needed. There it is preferable to use MKESH — it takes up less space and is easier to bend. When choosing, the environment is always taken into account: a dry room and a protected volume — MKESH, any other place — MKESHV.
Installation, Flexibility and Joints
Both cables are installed by soldering or crimping. The screen is earthed at one end for protection against low‑frequency interference and at both ends — for high‑frequency. When using MKESH, it is sufficient to carefully untwist the braid and twist a drain bundle; on MKESHV, the PVC sheath is first removed without damaging the braid. The bending radius of MKESH is 5 diameters, which is convenient in cramped instrument compartments. MKESHV is stiffer, its radius is 7 diameters, therefore more space is required on sharp turns. Termination for a joint or a terminal block is carried out according to the same rules: the outer layer is removed, the screen is earthed, the conductors are stripped. The specifics of working with signal and control cables are covered in the guides signal and control cable.
When to Choose MKESH
- Inside instrument enclosures, racks, automation cabinets. The space is limited and mechanical risks are minimal.
- Sealed volumes with a dry atmosphere — a sheath is not needed.
- Sections where maximum flexibility and a small bending radius are important, for example, when connecting moving measuring heads.
- Prototyping and one‑off samples, where price and ease of termination are more important than long‑term protection.
When to Choose MKESHV
- Inter‑unit connections laid along walls, in cable ducts, trays. The sheath protects the screen from abrasion against metal structures.
- Premises with increased humidity, temperature fluctuations, possible ingress of oil or water. The PVC sheath serves as a barrier.
- Facilities with fire requirements: ng, ng‑LS or FRLS versions are needed. MKESHV provides certified sheaths.
- Open routing, where aesthetics and colour identification are important. The sheath can be grey, white or black.
Typical Mistakes in Selection and Installation
- Laying MKESH outside an instrument compartment. The exposed braid quickly oxidises, loses contact with earthing and is destroyed, especially in a humid environment.
- Using MKESHV without removing the sheath in places where contact with the screen is needed. Some installers forget to strip the PVC and solder the earth on top of the sheath — there is no contact.
- Bending MKESHV with a radius of less than 7 diameters. The sheath and screen are deformed, the braid can burst, which disrupts the shielding.
- Choosing MKESH for a fire alarm system without taking into account the requirements for smoke formation. On escape routes, LS is required, and MKESH without a sheath cannot guarantee low smoke emission.
- Terminating MKESH without sealing the end. Moisture seeps under the braid and along the conductors puts the entire line out of service.
- A mistake in deciphering the marking: MKESH and MKESHV are confused. The presence of the letter “V” at the end is checked — it indicates a sheath.
Frequently Asked Questions
How are MKESH and MKESHV deciphered?
MKESH — instrumentation cable with a copper braid screen, polyethylene insulation. MKESHV — the same, but with an additional PVC sheath. The letter “V” denotes a vinyl (PVC) sheath.
What is the main difference between MKESH and MKESHV?
MKESH has no outer sheath, the screen is exposed. MKESHV has a PVC sheath that protects against moisture, dust and mechanical damage.
Which cable is better for outdoor installation?
Only MKESHV, moreover in a black PVC sheath resistant to ultraviolet. MKESH outdoors quickly corrodes and fails.
Can MKESHV be used inside devices?
It is possible, but irrational: it takes up more space, is less flexible and more expensive. Inside protected volumes, MKESH is sufficient.
What cross‑sections and conductor counts are available?
Typical cross‑sections: 0.35; 0.5; 0.75; 1.0; 1.5 mm². Number of conductors: 2, 3, 4, 5, 7, 10. Popular orders: 2×0.75, 3×0.75, 4×0.75, 7×0.75, 10×0.5, as well as twisted pairs — 2×2×0.75, 4×2×1 and others. Both types are produced with the same range.
Is a certificate required for MKESH and MKESHV?
Yes, a certificate of conformity to GOST 10348‑80 and a fire certificate for ng, LS, FRLS versions are required. A passport indicating the diameter and weight is provided by the manufacturer.
Conclusion
The choice between MKESH and MKESHV comes down to an assessment of the external conditions. If the cable operates inside a sealed device or cabinet, where it is dry and there are no mechanical impacts, MKESH will give an advantage in dimensions and flexibility. For any external routing, damp premises or facilities with fire requirements, MKESHV with its PVC sheath is necessary. Copper conductors, a high‑density screen and compliance with GOST 10348‑80 remain common to both types. The catalogue MKESHV presents all versions — from ordinary to FRLS, with the required cross‑sections and conductor counts.
