Engineering Analysis: What is NSHXAFÖ, and why is this single-core rubber cable used for “short-circuit-proof” installation in trains and buses?
Published by: Anhui Feichun Special Cable Co., Ltd.
Authority in Railway Rolling Stock and Switchgear Cabling Solutions
1. Executive Summary: The “Safety Margin” Cable
2. Decoding the Name: NSHXAFÖ
To understand the cable’s capabilities, we must decode its German VDE designation.
| Code (代码) | German Term (德语术语) | Technical Significance (技术意义) |
|---|---|---|
| N | Normenleitung | Standardized Cable according to VDE. 符合 VDE 的标准化电缆。 |
| S | Sondergummiaderleitung | Special Rubber Cable. Designed for heavier mechanical loads than standard cables. 特种橡胶电缆。 设计用于承受比标准电缆更重的机械负载。 |
| H | Halogenfrei | Halogen-Free. Does not emit toxic gases (chlorine/fluorine) during fire. Critical for public transport. 无卤。 火灾时不释放有毒气体（氯/氟）。对公共交通至关重要。 |
| X | Vernetzter Werkstoff | Cross-linked Insulation. Typically indicates a high-grade EPR or Cross-linked Polymer with improved thermal stability. 交联绝缘。 通常表示具有更高热稳定性的高级 EPR 或交联聚合物。 |
| A | Aderleitung | Single Core. This cable is only available as a single conductor. 单芯线。 该电缆仅提供单芯结构。 |
| F | Fassung (Rubber Sheath) | Refers to the specific rubber sheath construction in this standard context. 在此标准语境下指特定的橡胶护套结构。 |
| Ö | Ölbeständig | Oil Resistant. Can withstand hydraulic fluids and lubricants found in bogies and engine bays. 耐油。 可承受转向架和发动机舱中的液压油和润滑油。 |
3. The Core Concept: What is “Short-Circuit Proof”?
The Physics of Prevention: Standard cables rated for 1kV have relatively thin insulation. If two standard cables cross each other and vibrate (as they do on a train), the insulation can wear down, causing a phase-to-phase short circuit.
The NSHXAFÖ Solution: By using a cable rated for 3000V (3kV) in a 1000V system, the insulation wall thickness is significantly increased. This physical barrier is so robust that it is considered mechanically impossible for a short circuit to occur between cables under normal operating conditions. It renders the installation “inherently short-circuit proof” and “earth-fault proof.”
预防的物理原理： 额定电压为 1kV 的标准电缆绝缘层相对较薄。如果两根标准电缆相互交叉并振动（如在火车上），绝缘层可能会磨损，导致相间短路。
NSHXAFÖ 解决方案： 通过在 1000V 系统中使用额定电压为 3000V (3kV) 的电缆，绝缘壁厚显著增加。这种物理屏障非常坚固，被认为在正常操作条件下电缆之间发生短路在机械上是不可能的。这使得安装具有“本质短路保护”和“接地故障保护”特性。
| Application Scenario (应用场景) | Why NSHXAFÖ is Mandatory (为什么必须使用) |
|---|---|
| Before the Main Fuse (主熔断器之前) | Connections from the battery or pantograph to the main breaker have NO protection. A short circuit here is catastrophic. NSHXAFÖ prevents the fault from ever happening. 从电池或受电弓到主断路器的连接没有保护。此处的短路是灾难性的。NSHXAFÖ 防止故障发生。 |
| Switchgear Jumpers (开关柜跳线) | Inside crowded electrical cabinets, cables often touch. NSHXAFÖ allows safe “unfused” routing between busbars and breakers. 在拥挤的电气柜内部，电缆经常接触。NSHXAFÖ 允许在母线和断路器之间进行安全的“无熔断”布线。 |
4. Technical Construction: Built for Public Transport
At Anhui Feichun Special Cable Co., Ltd., we manufacture this cable to meet the rigorous safety demands of modern transit systems.
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Conductor: Tinned Copper, Class 5 Flexible (IEC 60228). Tinning prevents corrosion from sulfur in the rubber and improves solderability.
导体： 镀锡铜，第5类柔性 (IEC 60228)。镀锡可防止橡胶中硫的腐蚀并提高可焊性。 -
Insulation: EPR Type 3GI3. This high-grade ethylene propylene rubber offers superior thermal resistance (90°C continuous) compared to standard rubbers.
绝缘： EPR Type 3GI3。 这种高级乙丙橡胶比标准橡胶提供更优越的耐热性（连续 90°C）。 -
Sheath: Polymer Type HM3. This is the key “Halogen-Free” component. Unlike Neoprene (which contains Chlorine), HM3 does not emit thick black smoke or hydrochloric acid gas when burned.
护套： 聚合物 Type HM3。 这是关键的“无卤”组件。与氯丁橡胶（含氯）不同，HM3 燃烧时不会释放浓黑烟或盐酸气体。
NSGAFÖU is the older sibling. It uses a Chlorinated Rubber sheath (Neoprene/PCP).
NSHXAFÖ is the modern successor. It uses a Halogen-Free Polymer sheath.
Rule of Thumb: If it’s a tunnel, a subway, or a passenger bus, you MUST use NSHXAFÖ to meet toxicity standards (EN 45545-2). If it’s an outdoor diesel locomotive or industrial panel, NSGAFÖU might be acceptable.
NSGAFÖU 是老款型号。它使用氯化橡胶护套（氯丁橡胶/PCP）。
NSHXAFÖ 是现代继任者。它使用无卤聚合物护套。
经验法则： 如果是隧道、地铁或客车，您必须使用 NSHXAFÖ 以符合毒性标准 (EN 45545-2)。如果是户外柴油机车或工业面板，NSGAFÖU 可能是可以接受的。
5. Installation Guidelines (VDE 0298-3)
- Not for Direct Burial: Despite its robust rubber sheath, it is not armoured against digging tools.
不可直埋： 尽管其橡胶护套坚固，但它没有针对挖掘工具的铠装。 - Bending Radius:
Fixed: 6 x Diameter
Flexible: 10 x Diameter
弯曲半径： 固定：6 x 直径；柔性：10 x 直径。 - Temperature: -40°C to +90°C (Fixed).
温度： -40°C 至 +90°C（固定）。
Contact Anhui Feichun Special Cable Co., Ltd.
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Authoritative References & Standards:
- DIN VDE 0250-606: Special rubber-insulated single-core cables, halogen-free (NSHXAFÖ).
- DIN VDE 0100-520: Selection and erection of electrical equipment – Wiring systems (Short-circuit proof definition).
- EN 45545-2: Railway applications – Fire protection on railway vehicles.
- IEC 60332-1-2: Tests on electric and optical fibre cables under fire conditions.
