PVC Steel Wire Armored Power Cable

Same Tensile Strength as YJV32 for Vertical Installations

The steel wire armour is identical to YJV32 — same wire diameter series (0.8 to 2.5 mm), same G1A grade galvanised steel, same helical application. The tensile strength for vertical shaft hanging, the crush resistance for rocky direct burial, and the torsional tolerance for submarine crossings are all unchanged from the XLPE equivalent. Choosing VV32 over YJV32 does not compromise the mechanical performance; it only reduces the thermal performance of the insulation. For shaft depths and hanging-weight calculations, use the same armour tensile data as published for YJV32 at the same overall cable diameter.

10-15% Lower Unit Cost Than YJV32 at the Same Cross-Section

PVC insulation compound costs less than XLPE because it doesn’t require the peroxide cross-linking chemistry and continuous vulcanisation (CV) line production process. At the same cross-section, VV32 consistently costs 10-15 percent less per metre than YJV32. For large cable runs on budget-constrained infrastructure projects — typical in emerging markets where mine shaft power, waterway crossings, and basic industrial distribution are being built — this is a real saving. The caveat: if the load current requires a larger cross-section to stay within 70°C, the conductor cost premium for the larger VV32 may exceed the 10-15 percent insulation saving.

Direct Replacement for Legacy BS 6346 SWA Cable

BS 6346 — the British Standard for PVC-insulated SWA cable that was the dominant UK and Commonwealth armoured cable specification for decades — has been superseded by BS 5467 XLPE SWA for new installations, but large quantities of BS 6346 SWA remain in service globally. VV32 / NYRY is the like-for-like replacement cable for maintenance and repair work on BS 6346 installations: same 70°C insulation rating, same construction philosophy, interchangeable at joints and terminations without requiring the re-engineering that upgrading to XLPE would entail. For replacement jointing into existing BS 6346 runs, matching the insulation material avoids the different thermal ratings problem at the joint interface.

Armour Earthing Path as Circuit Protective Conductor

As with YJV32, the steel wire armour layer provides a low-resistance earth-continuity path when bonded to earth at both cable terminations via SWA armour glands. For LV installations, the armour is typically used as the circuit protective conductor (CPC), eliminating the need for a separate earth conductor in most 3-core or 4-core installations. Verify the armour cross-section satisfies BS 7671 Table 54.7 or IEC 60364-5-54 for the circuit’s earth-fault current and disconnection time. The armour earth path is a function of the steel wire construction; PVC vs XLPE insulation doesn’t affect the earth-path resistance.

Ampacity 30-40% Lower Than YJV32: Understand the Trade-Off

The critical disadvantage vs YJV32. PVC insulation rated at 70°C conductor temperature produces ampacity 30-40 percent lower than XLPE rated at 90°C at the same cross-section. A 4-core 95 mm² YJV32 in air carries approximately 293 A; the equivalent VV32 carries approximately 246 A. If the required current cannot be carried within the VV32 70°C limit at the available cross-sections, a larger cross-section must be specified — potentially erasing the insulation-cost saving. Always size VV32 from 70°C ampacity tables (not the 90°C XLPE tables used for YJV32) to ensure the conductor temperature limit is not exceeded.

IEC 60502-1 and BS 6346 Certified

Production certified to IEC 60502-1 as primary international reference for the VV32 / NYRY designation, plus BS 6346 for UK and Commonwealth replacement-installation acceptance, and AS/NZS 5000.1 for the Australian and New Zealand market. For European projects, the cable can be marked as NYRY per the European VDE/IEC designation. Note that BS 6346 is a superseded standard; UK electricity distribution network operators (DNOs) and most new UK installations specify BS 5467 XLPE cable for new work. BS 6346 certification is primarily relevant for replacement and repair work on existing legacy installations.

PVC insulation becomes brittle below −5°C and cracks during cable pulling and bending. For cold-weather installation, store the cable drum in a heated enclosure for 24 hours before installation day, and install the cable immediately after moving outside into cold ambient. The minimum installation temperature is 0°C for VV32; this is slightly less restrictive than XLPE (which is also 0°C) but both should be pre-heated in very cold conditions. Once the cable is installed and energised, conductor heating keeps the insulation above the brittle-point temperature during operating condition.

The single most important VV32-specific practice. Always size VV32 from the 70°C PVC conductor temperature tables — the same tables used for NYY. Never use the 90°C XLPE tables that apply to YJV32. Using the wrong tables consistently produces a cross-section one step smaller than needed for PVC, which will overheat in service within months. For any project switching from YJV32 specification to VV32, re-size all cable cross-sections from scratch using 70°C tables before ordering. A simple check: VV32 ampacity should be approximately 83-85 percent of the YJV32 value at the same cross-section — if the published value matches, you are using the correct table.

Identical requirement to YJV32: SWA cable termination requires proper armour cable glands that grip the steel wire layer circumferentially, providing both mechanical cable anchorage and a low-resistance earth-bonding connection. The gland body has an internal cone that compresses against the wire layer when the nut is tightened. Do not use standard PVC cable glands on SWA cable, and do not pigtail individual armour wires to a lug. The gland size is selected for the VV32 cable OD — at the same cross-section, VV32 is slightly larger OD than YJV32 (PVC insulation wall is slightly thicker than XLPE for the same voltage rating); verify the gland size against actual cable OD before ordering.

PVC insulation has a sharper failure mode than XLPE when the temperature limit is approached: PVC softens progressively above 70°C, accelerating plasticiser migration and insulation degradation in a self-reinforcing cycle. For VV32 circuits that regularly operate above 80 percent of rated ampacity, measure the cable sheath temperature during full-load operation (with a surface thermometer or thermal camera) to confirm the design sizing is correct in the actual installation environment. If sheath temperatures significantly exceed expectations, reduce load or improve ventilation before PVC degradation reaches an irreversible level.

Insulation resistance test (megger at 1 kV DC) between every conductor and earth (armour), and between adjacent conductors, before energising. For new VV32, expected reading is > 100 MΩ per km (lower baseline than XLPE, which is > 1000 MΩ — PVC has higher inherent moisture permeability than XLPE). Readings below 20 MΩ per km indicate water ingress or installation damage requiring investigation before energising. Document the test results in the project handover as the baseline; repeat annually or on any event suggesting cable damage. PVC cable insulation resistance tends to decrease more with age than XLPE, making the baseline record particularly valuable for VV32 maintenance planning.