Detailed Description
What Is PVC Sheathed Cable?
A PVC sheathed cable is a multi-core cable in which all insulated conductors are enclosed within a single outer PVC (polyvinyl chloride) jacket — a one-piece circular sheath that provides mechanical protection, electrical insulation between the internal cores and the external environment, and color-coded identification. The construction is PVC-insulated conductors + PVC outer sheath, denoted by the "VV" designation in cable type codes (e.g., H05VV-F: Harmonized, 300/500V, PVC insulation, PVC sheath, Flexible conductor).
PVC sheathed cable is the most common multi-core cable in everyday use. The power cord on a domestic appliance (white, 3-core, flexible), the grey cable running along the wall to a light switch (NYM, solid conductor, fixed), the orange cable connecting a workshop machine to the wall isolator (H07VV-F, 4-core, heavy flexible) — these are all PVC sheathed cables. The PVC sheath is what makes a bundle of insulated conductors into a single, handleable, installable cable.
In the IEC world, PVC sheathed cables are organized by their intended use:
- Flexible cords (IEC 60227-5, HD 21.5): For connecting portable appliances and equipment. The PVC sheath is formulated for flexibility (higher plasticizer content) and the cable withstands occasional bending and coiling
- Fixed installation cables (IEC 60227-4, HD 21.4): For permanent wiring in buildings. The PVC sheath is semi-rigid, formulated for mechanical protection and long-term dimensional stability rather than flexibility
H05VV-F vs H07VV-F — Voltage and Duty Ratings
| Parameter | H05VV-F | H07VV-F |
|---|---|---|
| Voltage rating | 300/500 V | 450/750 V |
| Conductor cross-section | 0.75–2.5 mm² | 1.5–35 mm² |
| Typical core count | 2–3 core (domestic appliances) | 3–5 core (industrial equipment) |
| Duty | Light duty — domestic appliance leads, office equipment, table lamps | Medium duty — portable industrial tools, machine connections, workshop distribution |
| Mechanical strength | Light — the sheath is thinner and designed for indoor domestic use | Medium — thicker sheath for industrial handling and occasional outdoor use |
| Temperature (moving) | -5°C to +50°C | -5°C to +50°C |
| Typical example | 3G1.0 mm² white PVC — the cable on a domestic kettle or toaster | 5G4 mm² black PVC — connecting a 3-phase machine tool to the factory isolator |
The "05" vs "07" prefix in the harmonized designation directly indicates the voltage class: 05-series cables are for 300/500 V (light domestic), 07-series for 450/750 V (industrial). For any application where the cable may be subject to mechanical stress beyond simple indoor domestic use — a factory floor, a workshop, a construction site — H07VV-F is the minimum specification.
NYM — The Building Cable with a Difference
NYM is the standard PVC sheathed cable for fixed installation in buildings across Europe. It differs from a simple PVC/PVC cable in one important detail: the space between the insulated cores is filled with a non-hygroscopic moisture-resistant filler compound. This filler serves three purposes:
- Circular cross-section: The filler fills the valleys between the round insulated cores, giving the cable a perfectly circular profile. This makes the sheath uniform in thickness and the cable easier to seal in standard cable glands
- Longitudinal moisture barrier: If the outer sheath is damaged at one point, the filler compound prevents water from migrating along the cable between the cores — the moisture path is blocked by the filler, protecting the insulation of adjacent cores
- Mechanical stability: The filled cross-section distributes compressive forces evenly, preventing the cores from cutting into each other under sustained mechanical load (e.g., when the cable is clamped under a cable clip)
PVC Sheath Properties — What the Jacket Provides
| Property | PVC Sheath Performance | Notes |
|---|---|---|
| Electrical insulation | Full rated voltage withstand between internal conductors and the external environment | The sheath is an insulating layer, not just mechanical — it contributes to the cable's voltage rating |
| Mechanical abrasion | Moderate — PVC resists light abrasion from handling and cable clips | For heavy abrasion (dragging, construction site), specify rubber or PUR sheath |
| Flame retardance | Excellent — PVC is inherently flame-retardant; self-extinguishing per IEC 60332-1-2 | The chlorine content (57% by weight of the PVC polymer) provides the flame-retardant mechanism |
| Water resistance | Moderate — PVC is water-resistant but not water-blocked; water can permeate slowly over time | For permanent wet or submerged conditions, specify PE-sheathed or rubber cable |
| UV resistance | Good (black, carbon-black reinforced); poor (white, grey — degrades with UV) | White or grey PVC cable should not be installed outdoors or in direct sunlight |
| Chemical resistance | Limited — PVC is attacked by hydrocarbons, oils, ketones, and esters; good resistance to acids, alkalis, and aqueous salt solutions | Do not install PVC sheathed cable in contact with mineral oils or organic solvents |
| Temperature range | -5°C to +70°C (flexible types, limited by plasticizer); -30°C to +70°C (fixed types) | PVC loses flexibility below 0°C — do not bend or install PVC sheathed cable at low temperatures without pre-heating |
| Recyclability | Good — PVC is mechanically recyclable; the PVC/PVC construction means the insulation and sheath are the same material chemistry | Pure PVC cable is easier to recycle than mixed-material cables (e.g., PVC insulation + PE sheath) |
Why Choose Yichi PVC Sheathed Cables
- H05VV-F, H07VV-F, and NYM from a single manufacturer: The complete PVC sheathed cable range — flexible appliance cords, industrial flexible cables, and building installation cables — manufactured with the same PVC compound family and the same quality system
- IEC 60227 / HD 21 harmonized and certified: All cables carry the HAR (CENELEC harmonized) marking where applicable and are tested to the full IEC 60227 test schedule — conductor resistance, insulation resistance, high-voltage withstand, cold bend, hot pressure, and flame propagation
- NYM with moisture-resistant filler construction: The filler is not a cost-reduction measure — it is a functional element that provides the longitudinal moisture barrier and circular cross-section that define the NYM type. Our NYM filler compound is tested for moisture resistance per VDE 0250-204
- Standard and custom color coding: White, black, and grey sheaths in standard domestic and industrial colors; custom core color coding for national markets with non-harmonized wiring codes; printed sheath marking with cable type, cross-section, and approval marks
- Full cut-length and packaging: Standard 50 m and 100 m coils for electrical wholesaler supply; 500 m and 1 000 m drums for construction projects; custom lengths cut to order for panel builders and OEM equipment manufacturers