Universal installation cables "twisted pair" GERDA-KV (KP, KPs)

GERDA-KV, GERDA-KP, and GERDA-KPs cables are manufactured with tinned copper (by default) or untinned “m” multi-wire conductors of at least class 3, and for a cross-section of 0.35 mm², at least class 4.

The nominal conductor cross-sections and the number of pairs are specified in Table 2. It is allowed to manufacture cables with a different number of pairs and nominal conductor cross-sections, as well as with a combined conductor cross-section.

For fire-resistant “FR” cables, a wrapping of two mica-containing tapes is applied over the current-carrying conductors, preventing short circuits in the event of a fire.

The conductor insulation can be made of:

• PVC compound “B” (GERDA-KV),
• halogen-free polymer composition “P” (GERDA-KP),
• cross-linked polyolefin “Ps” (GERDA-KPs).

Conductor marking can be color-coded or numerical.

The conductors are twisted into pairs with a twist pitch of no more than 60 mm. In fire-resistant cables with a conductor cross-section of 1.5 mm² and 2.5 mm², the twist pitch is slightly larger to make the cable more circular and reduce its diameter.

Each conductor pair can have an individual shield:

• “e” – braid of tinned copper wires,
• “em” – braid of copper wires,
• “ea” – wrapping of aluminum foil tape (alumoflex) with a multi-wire tinned copper drain wire,
• “emf” – wrapping of copper foil tape with a multi-wire tinned copper drain wire.

An insulating polymer film is applied over the individual shield of each pair, preventing electrical contact between adjacent shields. Instead of a polymer film, an extruded polymer layer “v” can be applied, ensuring reliable insulation between pair shields.

The conductor pairs are twisted into a core, over which a water-blocking tape is applied to prevent longitudinal moisture penetration in case of outer sheath damage. A common shield can be applied over the water-blocking tape.

Types of common shields:

• braid of copper wires (by default),
• “L” – braid of tinned copper wires,
• “Ea” – wrapping of aluminum foil tape (alumoflex) with a multi-wire tinned copper drain wire,
• “Emf” – wrapping of copper foil tape with a multi-wire tinned copper drain wire,
• “EaL” – combined shield in the form of alumoflex, over which a braid of tinned copper wires is applied.

An extruded separation layer is applied over the common shield, filling the free spaces between conductors (in accordance with GOST IEC 60079-14-2013). As a result, the cable cross-section becomes circular (allowing it to be used with any type of cable entry) and, in case of cable damage, an explosive gas mixture cannot penetrate under the sheath from the hazardous area into the safe area. By agreement with the customer, cables of non-circular shape (without extruded filling) can be manufactured.

The cables can have armor made of galvanized steel wires “K” (GERDA-KVK, GERDA-KPK, GERDA-KPsK) or galvanized steel tapes “B” (GERDA-KVB, GERDA-KPB, GERDA-KPsB).

The cable sheath is made of PVC compounds or halogen-free polymer composition (see Table 3). The sheath color is determined in the order code. If not specified, the cables are manufactured in black.  

Cables can be manufactured in special versions:

• “T” – heat-resistant (up to +120°C),
• “HL” – cold-resistant,
• “EHL” – resistant to extremely cold conditions, cable installation possible at temperatures down to -40°C,
• “UF” – resistant to solar radiation,
• “H” – resistant to acids, alkalis, and environments with high hydrogen sulfide content,
• “M” – oil and fuel resistant,
• “ZG” – sheath resistant to rodents, ants, and termites.

Custom cable manufacturing:

• with a colored outer sheath (orange, red, yellow, or other colors)
• with a combined conductor cross-section for pairs
• hybrid transmission cables – transmitting electrical power (via current-carrying conductors) and optical signals (via optical fibers) in a single cable