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: DIN VDE 0250-204 (HD 21.4 / IEC 60227-4).
· 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: NYMHY-type — DIN VDE 0281-5 (HD 21.5 / EN 50525-2-11) 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 0250-204 (HD 21.4) · IEC 60227-4 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 | Blue + Brown + Black + Grey + 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 (1100V) | NYM test voltage | IS 694:2010 test voltage |
|---|---|---|---|---|
| 1.5 | 0.7 mm | 0.7 mm | 2.0 kV | 3.0 kV |
| 2.5 | 0.8 mm | 0.8 mm | 2.0 kV | 3.0 kV |
| 4.0 | 0.8 mm | 0.8 mm | 2.0 kV | 3.0 kV |
| 6.0 | 0.8 mm | 0.8 mm | 2.0 kV | 3.0 kV |
| 10.0 | 1.0 mm | 1.0 mm | 2.0 kV | 3.0 kV |
| 16.0 | 1.0 mm | 1.0 mm | 2.0 kV | 3.0 kV |
| 25.0 | 1.2 mm | 1.2 mm | 2.0 kV | 3.0 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 0250-204 / 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 | 18.5 | 12.1 |
| 2.5 | 18 | 24 | 25 | 7.41 |
| 4.0 | 24 | 32 | 34 | 4.61 |
| 6.0 | 31 | 41 | 43 | 3.08 |
| 10.0 | 42 | 57 | 60 | 1.83 |
| 16.0 | 56 | 76 | 80 | 1.15 |
| 25.0 | 73 | 96 | 101 | 0.727 |
| 35.0 | 89 | 119 | 126 | 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 0250-204 building cable — technical questions answered.
Common questions from electrical contractors, engineers, and importing partners specifying NYM family cables to VDE 0250-204 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. NYMHY-type construction per DIN VDE 0281-5 (HD 21.5 / EN 50525-2-11), Class 5 conductor per IEC 60228, with 6× OD bending radius during installation.
What is VDE 0250-204 and why is it important for German and European projects?
VDE 0250-204 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 0250-204 cables dominate German, Austrian, Eastern European, and Middle Eastern building markets. Many national building codes reference or adopt VDE 0250-204 specifications. Non-VDE compliant cables are typically rejected at site inspection in these markets.
National Cables manufactures the NYM family to VDE 0250-204 specification on BIS-certified IS 694:2010 production lines (CM/L-8800140116), with third-party testing available 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 0250-204.
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 0250-204 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.