{"id":1885,"date":"2026-06-25T06:39:45","date_gmt":"2026-06-25T06:39:45","guid":{"rendered":"https:\/\/zeeyielec.com\/?p=1885"},"modified":"2026-06-25T06:41:11","modified_gmt":"2026-06-25T06:41:11","slug":"cold-shrink-cable-termination-kits-mv-underground","status":"publish","type":"post","link":"https:\/\/zeeyielec.com\/ru\/cold-shrink-cable-termination-kits-mv-underground\/","title":{"rendered":"10 \u043b\u0443\u0447\u0448\u0438\u0445 \u043a\u043e\u043c\u043f\u043b\u0435\u043a\u0442\u043e\u0432 \u0434\u043b\u044f \u043e\u043a\u0430\u043d\u0442\u043e\u0432\u043a\u0438 \u0442\u0435\u0440\u043c\u043e\u0443\u0441\u0430\u0434\u043e\u0447\u043d\u044b\u0445 \u043a\u0430\u0431\u0435\u043b\u0435\u0439, \u043f\u0440\u0435\u0434\u043d\u0430\u0437\u043d\u0430\u0447\u0435\u043d\u043d\u044b\u0445 \u0434\u043b\u044f \u043f\u043e\u0434\u0437\u0435\u043c\u043d\u044b\u0445 \u043a\u0430\u0431\u0435\u043b\u0435\u0439 \u0441\u0440\u0435\u0434\u043d\u0435\u0433\u043e \u043d\u0430\u043f\u0440\u044f\u0436\u0435\u043d\u0438\u044f"},"content":{"rendered":"\n

Cold shrink cable termination kits for MV underground cables must be matched to the cable, not picked from a catalog. The right kit has to match the cable’s voltage class, conductor area, outer diameter, insulation chemistry, and where the cable surfaces \u2014 miss any one and it won’t recover or grade the field correctly.<\/p>\n\n\n\n

How Cold Shrink Terminations Work on MV Underground Cables<\/h2>\n\n\n\n

A cold shrink termination restores the insulation, grades the electric field, and seals the cable end without any applied heat. Instead of a torch, the kit relies on a pre-expanded silicone rubber (or EPDM) body held open by a removable internal support core. When the installer withdraws the core, the elastomer contracts radially onto the cable, generating continuous interface pressure that follows thermal expansion and contraction over a service life often targeted at 25\u201340 years. Four functional elements do the work.<\/p>\n\n\n\n

Pre-expanded silicone insulation body<\/h3>\n\n\n\n

The silicone body re-establishes the radial insulation lost at cutback. Its constant residual squeeze keeps the interface void-free as load cycling moves the conductor \u2014 which is why cold shrink performs well in damp duct banks where heat-shrink installers struggle to apply even heat.<\/p>\n\n\n\n

Removable support core<\/h3>\n\n\n\n

The spiral-wound plastic core is the defining mechanism. The installer positions the assembly, then unwinds the core so the body collapses onto the cable in one motion \u2014 no flame, no measured shrink temperature, no risk of scorching the primary insulation.<\/p>\n\n\n\n

Stress-control (field-grading) element<\/h3>\n\n\n\n

At the cutback of the cable’s semiconductive screen, the electric field concentrates sharply. A high-permittivity stress-control layer redistributes that field; typical geometric stress cones or high-K materials operate with relative permittivity of roughly 15\u201330, smoothing a discharge-prone edge.<\/p>\n\n\n\n

The unmanaged field at the screen edge can reach local gradients several times the bulk average; the grading element targets a surface tangential stress on the order of \u2264 0.5 kV\/mm to suppress partial discharge inception. Interface radial pressure from the silicone is commonly held in the \u2248 0.05\u20130.15 N\/mm\u00b2 band to maintain a void-free interface across thermal cycles.<\/p>\n\n\n\n

Environmental seal<\/h3>\n\n\n\n

Integral mastics and the silicone skirt block moisture ingress at the lug and the cable jacket entry \u2014 the dominant failure path underground. PD test criteria for this class are framed by the IEC 60502-4 cable-accessory family [VERIFY STANDARD: IEC 60502-4 termination test requirements], which governs type and routine testing rather than any single manufacturer’s claim.<\/p>\n\n\n\n

\"Cold
Cross-section of a medium-voltage cold shrink termination identifying the pre-expanded silicone body, spiral support-core path, stress-control cone at the semiconductive cutback, and lug and jacket seals.<\/figcaption><\/figure>\n\n\n\n

These elements explain why selection can’t reduce to voltage class alone \u2014 the focus of the cable accessories range<\/a> and the criteria below.<\/p>\n\n\n\n

How to Choose a Cold Shrink Kit: Selection Criteria<\/h2>\n\n\n\n

Five parameters decide whether a kit is usable on a given cable.<\/p>\n\n\n\n

Voltage class matching<\/h3>\n\n\n\n

Match the kit to the cable’s rated voltage U\u2080\/U and its maximum system voltage Um, not the nominal number alone. MV underground families typically split into an 8.7\/15 kV class and a 26\/35 kV class, with insulation and creepage sized accordingly.<\/p>\n\n\n\n

Confirm that the kit’s rated Um \u2265 the system’s highest voltage. An 8.7\/15 kV (Um = 17.5 kV) kit must never be applied on a 26\/35 kV (Um = 40.5 kV) circuit, even briefly during commissioning \u2014 the stress-control element is dimensioned for a specific gradient band.<\/p>\n\n\n\n

Conductor size and cable OD fit window<\/h3>\n\n\n\n

This is where most field rejections originate. Cold shrink bodies recover only within a defined diameter band, so the measured OD over the insulation must fall inside the kit’s window. Conductor ranges commonly span 25\u2013630 mm\u00b2, reaching 800 mm\u00b2 on primary feeders, but the governing number is the measured OD, not the copper area. Always measure the actual insulation diameter \u2014 datasheets and as-laid cables drift by 1\u20132 mm often enough to push a marginal selection out of range.<\/p>\n\n\n\n

Indoor vs outdoor \/ underground transition type<\/h3>\n\n\n\n

A cable that stays in a duct or pit uses an indoor body; one that surfaces into air, sunlight, or pollution needs an outdoor variant with sheds and a tracking-resistant surface. Specifying an indoor kit at a riser pole is a recurring commissioning defect.<\/p>\n\n\n\n

Insulation type compatibility<\/h3>\n\n\n\n

Confirm the kit is rated for the cable’s insulation \u2014 almost always XLPE or EPR on MV distribution. The semicon screen type (extruded vs taped) changes the cutback procedure, so verify it before cable prep, not at the splice.<\/p>\n\n\n\n

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[Expert Insight] Pre-RFQ selection check<\/strong><\/p>\n\n\n\n