What Is NYM (Antigron) Cable? Damp-Area Wiring vs H05VV-F and NYY
Construction and installation rules of 300/500 V NYM (antigron) installation cable under DIN VDE 0250-204, damp-location wiring limits, and differences from H05VV-F (TTR) and NYY.
NYM cable (commonly called antigron cable in Turkish installation practice) is a 300/500 V multi-core fixed installation cable manufactured to DIN VDE 0250-204. Featuring solid or stranded copper conductors, PVC core insulation, an extruded non-hygroscopic inner filling compound, and a light-grey PVC outer sheath, it is engineered for surface-mounted, flush-mounted, and tray installations in dry, dusty, or damp indoor spaces.
> Related Category: Compare cross-sections and technical specifications directly in NYM (Antigron) Cables, TTR Cables, and NYY Cables.
VDE letter code and 4-layer construction
Each letter in NYM denotes a structural layer under the VDE designation system:
- N: Standard norm installation cable.
- Y: Thermoplastic PVC conductor insulation (70 °C continuous conductor temperature).
- M: Sheathed installation cable (*Mantelleitung*) incorporating an unvulcanized elastomer filling sheath around the laid-up cores plus a tough grey PVC outer jacket.
The extruded inner filler eliminates interstitial air gaps, prevents capillary moisture migration along the cable, maintains a uniform circular profile for IP54–IP65 compression cable glands on junction boxes, and makes stripping clean without sticking to the core insulation. NYM-J includes a green-yellow protective earth (PE) core; NYM-O omits the green-yellow core.
Technical comparison: NYM vs TTR (H05VV-F) vs NYY
| Parameter | NYM (Antigron) | TTR (H05VV-F) | NYY (Power Cable) |
|---|---|---|---|
| Rated voltage (U0/U) | 300/500 V | 300/500 V | 0.6/1 kV (600/1000 V) |
| Copper class (IEC 60228) | Class 1 solid (≤10 mm²) or Class 2 stranded (≥16 mm²) | Class 5 fine-wire flexible | Class 1 solid or Class 2 stranded |
| Extruded inner filler | Yes (moisture-blocking round profile) | No | Yes (heavy-duty mechanical & moisture barrier) |
| Outer sheath | Light grey PVC | White or black PVC | UV-stabilized black PVC |
| Fixed damp indoor areas (basements, workshops) | Yes (primary application) | Not intended for permanent fixed building wiring | Yes |
| Portable appliances & extension leads | No (rigid cores fatigue under flexing) | Yes (primary application) | No |
| Direct burial & outdoor UV exposure | No | No | Yes |
For deeper comparisons, see TTR vs NYY cable difference and NYA, NYAF, and H05VV-F cable difference.
Permitted vs prohibited installation environments
Permitted:
- Surface clipping, perforated cable trays, and conduit runs in basements, garages, utility rooms, boiler rooms, and damp workshops.
- Flush-mounted wiring in plaster and masonry walls.
Prohibited:
- Direct burial in soil: 300/500 V NYM is not rated for underground soil pressure or continuous groundwater; specify 0.6/1 kV NYY cables instead.
- Unprotected outdoor sunlight (UV): Light-grey PVC degrades and cracks under direct ultraviolet radiation unless enclosed in UV-resistant conduit.
- Vibrated poured concrete and moving machinery: Mechanical vibration during concrete compaction can damage the jacket, while flexing applications require Class 5 flexible cords.
- High-occupancy escape routes requiring halogen-free cables: Public buildings and escape corridors require LSZH cables such as N2XH.
Frequently asked questions
Are antigron cable and NYM cable the same product?
Yes. Antigron is the traditional field term used for grey, filler-sheathed NYM damp-location installation cables; engineering schedules specify NYM or NYM-J (with green-yellow earth conductor).
Can NYM cable be buried directly underground?
No. NYM is rated 300/500 V and is prohibited for direct burial in soil or unprotected outdoor UV exposure; use 0.6/1 kV black-sheathed NYY cable underground.
Why choose NYM instead of H05VV-F (TTR) for surface damp-area wiring?
NYM contains an extruded non-hygroscopic filler layer that seals neatly inside IP-rated cable glands and uses Class 1 solid conductors for rigid, reliable screw/spring terminal clamping without ferrules.
Which core colors are inside a 3-core NYM-J cable?
Under HD 308 S2, a 3G cable contains brown (phase L), light blue (neutral N), and green-yellow (protective earth PE).