NYM-J / NYM-O
German-standard sheathed multicore building cable.
NYM is the dominant multicore sheathed building cable in German-influenced markets — Germany, Austria, Eastern Europe, Turkey, East Africa, and the Middle East. PVC-insulated cores in a PVC outer sheath, Class 1 solid or Class 2 stranded conductor, 300/500V. Available with earth core (NYM-J) or without (NYM-O).
NYM — the German code system decoded.
The NYM designation follows the German VDE coding system. Each letter encodes a construction characteristic: N = Normleitung (standard cable — VDE) · Y = PVC insulation · M = PVC sheath (multiple cores, round construction). The suffix encodes earth and flexibility: J = with green/yellow earth · O = without earth (Ohne Schutzleiter) · K = flexible Class 5 conductors (paired with J or O for earth variants).
| Variant | Conductor class | Earth core | Primary application |
|---|---|---|---|
| NYM-J | Class 1 / 2 (Rigid) | Included | Fixed power wiring in conduit or under plaster. |
| NYM-O | Class 1 / 2 (Rigid) | Omitted | Control and signaling circuits without earth requirement. |
| NYM-K | Class 5 (Flexible) | J or O variants | Industrial machinery wiring and panel-to-machine leads. |
Standard Export Configurations
These specifications represent the primary volume drivers for residential and light-industrial German-standard projects.
3G1.5 NYM-J (Rigid)
Standard: VDE 0281-1.
· Cores: 3 (Brown, Blue, Green/Yellow)
· Conductor: Class 1 solid
· Common use: Lighting and socket feeds in plaster or conduit.
3G2.5 NYM-K (Flexible)
Standard: VDE 0281-3 equivalent.
· Conductor: Class 5 fine-stranded
· Flexing bending radius: 6× OD
· Common use: Machinery power leads and panel internal wiring.
The NYM Family: Rigid (NYM) vs. Flexible (NYM-K)
Class 1 or 2 conductor
Class 5 fine-stranded
Construction and electrical characteristics.
| Parameter | Value |
|---|---|
| Standard | DIN VDE 0281-1 · IEC 60227 equivalent construction |
| Rated voltage (U₀/U) | 300/500V |
| Conductor | Plain annealed copper · Class 1, 2, or 5 (Flexible) · IEC 60228 / IS 8130. |
| Conductor sizes | 1.5mm², 2.5mm², 4mm², 6mm², 10mm², 16mm², 25mm², 35mm² |
| Insulation | PVC Type TI1 · colour coded per DIN VDE 0293/HD 308 |
| Sheath | PVC — grey (standard) · round construction |
| Core count | 1, 2, 3, 4, 5 core (standard) · up to 12 core available |
| Max conductor temperature | 70°C continuous · 160°C short circuit (5s) |
| Test voltage | 2.0kV AC (1 min) |
| Flame retardant | IEC 60332-1-2:2004 / IEC/EN 60332-1 |
| Min installation temp | +5°C (bending/installation) · −40°C (fixed service) |
| Min bending radius | 6 × OD (installation) · 4 × OD (fixed, after installation) |
| Sheath colour | Grey (standard) · can be supplied black or white on order |
MTO sequential meter marking and custom VDE-compliant inkjet strings available for site accountability.
Standard core colour coding — per DIN VDE 0293 / HD 308 S2.
| Core Count | NYM-J (with earth) | NYM-O (without earth) |
|---|---|---|
| 2-core | Brown + Blue | Brown + Blue |
| 3-core | Brown + Blue + Green/Yellow | Brown + Black + Grey |
| 4-core | Brown + Black + Grey + Green/Yellow | Brown + Black + Grey + Blue |
| 5-core | Brown + Black + Grey + Blue + Green/Yellow | Brown + Black + Grey + Blue + Black |
IS 694:2010 domestic multicore colour code (Red/Yellow/Blue/Black/Green) differs from DIN VDE 0293. Export NYM is manufactured with DIN VDE colour coding as standard.
Same wall thickness. Higher voltage rating.
| Size (mm²) | NYM insulation (300/500V) | IS 694:2010 insulation (650/1100V) | NYM test voltage | IS 694:2010 test voltage |
|---|---|---|---|---|
| 1.5 | 0.7 mm | 0.7 mm | 2.0 kV | 2.5 kV |
| 2.5 | 0.8 mm | 0.8 mm | 2.0 kV | 2.5 kV |
| 4.0 | 0.8 mm | 0.8 mm | 2.0 kV | 2.5 kV |
| 6.0 | 0.8 mm | 0.8 mm | 2.0 kV | 2.5 kV |
| 10.0 | 1.0 mm | 1.0 mm | 2.0 kV | 2.5 kV |
| 16.0 | 1.0 mm | 1.0 mm | 2.0 kV | 2.5 kV |
| 25.0 | 1.2 mm | 1.2 mm | 2.0 kV | 2.5 kV |
Same physical construction, certified to a higher dielectric standard. National Cables applies a 3.0kV AC routine test to all MTO NYM orders, exceeding the VDE 2.0kV baseline.
3-core OD: rigid NYM-J vs. flexible NYM-K.
Class 5 flexible conductors yield a slightly larger overall diameter (OD) than rigid Class 1/2 NYM-J for the same copper cross-section — a key detail for engineering contractors at the design stage. Reference per DIN VDE 0281-1 / project datasheets; confirm on MTO release.
| Size (mm²) | Insul. (mm) | NYM-J (Rigid) 3-core OD | NYM-K (Flex) 3-core OD | Max R Rigid (Ω/km) | Max R Flex (Ω/km) |
|---|---|---|---|---|---|
| 1.5 | 0.7 | 9.1 | 9.5 | 12.1 | 13.3 |
| 2.5 | 0.8 | 10.4 | 10.9 | 7.41 | 7.98 |
| 4.0 | 0.8 | 12.0 | 12.5 | 4.61 | 4.95 |
6–35mm², 4/5-core, and 7/10/12-core rigid matrices — contact us for full dimensional and weight data.
3-core NYM-J — rated current, 70°C PVC, per IEC 60364-5-52.
Values per IEC 60364-5-52 Table B.52.4 for 3 loaded copper conductors, PVC insulation, 70°C conductor, 30°C ambient.
| Size (mm²) | Method B (A) Conduit on wall / trunking | Method C (A) Clipped direct to surface | Method E (A) Free air / perforated tray | Max R Ω/km |
|---|---|---|---|---|
| 1.5 | 13.5 | 17.5 | 18 | 12.1 |
| 2.5 | 18 | 24 | 24 | 7.41 |
| 4.0 | 24 | 32 | 32 | 4.61 |
| 6.0 | 31 | 41 | 40 | 3.08 |
| 10.0 | 42 | 57 | 54 | 1.83 |
| 16.0 | 56 | 76 | 73 | 1.15 |
| 25.0 | 73 | 96 | 95 | 0.727 |
| 35.0 | 89 | 119 | 117 | 0.524 |
Method B: multicore enclosed in conduit on wall or in trunking. Method C: multicore clipped direct to surface. Method E: multicore in free air or on perforated tray.
Ambient temperature correction — 70°C PVC.
Values above at 30°C ambient. Multiply the tabulated rating by the factor for your site ambient temperature.
Per IEC 60364-5-52 Table B.52.14 (70°C thermoplastic PVC). Example: 4mm² NYM-J clipped direct at 45°C ambient: 32 × 0.79 = 25A.
Where NYM is specified.
Approved NYM-J feeds for LCL/FCL project supply to UAE, Jordan, and East Africa.
The IS 694:2010 product NYM is manufactured from.
Looking for Halogen-Free?
For metro, hospital, and airport projects requiring zero-halogen performance, we supply the (N)HM-J sheathed LSZH equivalent. View the LSZH Building Wire Family →
NYM VDE 0281 building cable — technical questions answered.
Common questions from electrical contractors, engineers, and importing partners specifying NYM family cables to VDE 0281 for German-market and European building projects.
What is the difference between NYM-J, NYM-O, and NYM-K?
NYM-J — Multi-core sheathed cable with protective earth core (green/yellow conductor). Specified for residential and commercial power distribution where grounding is required by building code. Class 1 (solid) or Class 2 (stranded) conductor options; common configurations include 3G1.5, 3G2.5.
NYM-O — Same construction as NYM-J but without earth core. Used for signaling, control circuits, and lighting feeds in systems that don't require a separate protective conductor. Also available in Class 1 and Class 2.
NYM-K — Class 5 fine-stranded flexible variant of NYM-J or NYM-O. Used for machinery power leads, panel-internal wiring, and applications requiring repeated bending. Meets VDE 0281-3 flexibility requirements with 6× OD bending radius during installation.
What is VDE 0281 and why is it important for German and European projects?
VDE 0281 is the German Institute for Electrotechnology (Verband der Elektrotechnik Elektronik Informationstechnik) standard for sheathed round installation cables. It specifies construction, materials (PVC insulation and sheath), voltage rating (300/500V), flame performance (IEC 60332-1-2), and conductor sizing per IEC 60228.
VDE 0281 cables dominate German, Austrian, Eastern European, and Middle Eastern building markets. Many national building codes reference or adopt VDE 0281 specifications. Non-VDE compliant cables are typically rejected at site inspection in these markets.
National Cables manufactures NYM family to full VDE 0281 specification with BIS certification and third-party testing for export conformance.
What is the maximum operating temperature and current rating for NYM cable?
Continuous rating: 70°C maximum conductor temperature at 30°C ambient. This is standard for PVC Type TI1 insulation per VDE 0281.
Short-circuit rating: 160°C for 5 seconds maximum during fault conditions.
Current capacity: Depends on conductor cross-section and ambient temperature. A 3G2.5 NYM-J in free air at 30°C carries approximately 20–25A; derating applies proportionally above 30°C ambient. Refer to published current-carrying tables for specific sizing or contact us for technical guidance.
Installation temperature minimum is +5°C (bending/pulling) and −40°C (fixed service).
Can NYM cable be directly buried or installed in damp environments?
NYM per VDE 0281 is not recommended for direct burial or prolonged submersion. The PVC outer sheath provides moisture resistance but is not rated as a direct-burial sheath; cable jacket degradation occurs over time in wet soil.
For outdoor/damp installations:
- Underground runs: Use NYCY (with copper earthing tape) inside conduit or protective duct.
- Exposed damp locations: Install inside rigid conduit or wall-mounted trunking to protect from UV and moisture.
- Wet areas (kitchens, bathrooms): Embed in plaster or install behind water-resistant wall paneling.
Contact our technical team for damp-environment cable selection if standard NYM doesn't fit your application.
Enquire for NYM export supply.
Specifications, core counts, MOQ and lead time for your project — 24-hour response.