N2XSH cable is a screened copper power cable with XLPE insulation and a low-smoke, halogen-free outer sheath. The medium-voltage single-core design described here serves fixed power circuits where cable fire behaviour is an important part of the route specification.
Its defining difference from PVC- or PE-sheathed MV alternatives is the outer-sheath system, not a change from XLPE insulation. Electrical rating, mechanical protection and reaction-to-fire classification remain separate requirements. Low-smoke halogen-free construction does not by itself establish operation during a fire.
بناء
- Phase conductor
- Stranded copper, فصل 2
- نظام العزل
- XLPE between inner and outer semiconductive layers
- شاشة معدنية
- Copper wires; associated tape arrangement follows the declared design
- Outer protection
- Low-smoke, halogen-free sheath; unarmoured reference
صفات
- MV designations
- 6/10, 12/20 و 18/30 كيلو فولت; voltage-specific constructions
- Reference table
- أحادي النواة 12/20 (24) كيلو فولت, 95 ل 500 mm² selected sizes
- تثبيت
- Fixed distribution, building supply and industrial cable routes
- Performance basis
- Electrical, دخان, gas and flame tests assessed separately
N2XSH Project Enquiries
Discuss the voltage, conductor section, screen duty and fire-performance requirements with XWA.
دخان منخفض, Halogen-Free and Flame Behaviour
A cable route through an occupied building or an enclosed service area can have different fire requirements from an external feeder. N2XSH addresses the sheath side of that specification while retaining the screened XLPE construction of an MV circuit. Its suitability depends on the complete declared design, not the abbreviation alone.
| Property | What it establishes | What it does not establish |
|---|---|---|
| Smoke emission | Smoke behaviour under the specified cable-burning test, مثل اللجنة الانتخابية المستقلة 61034-2. | No smoke under every possible fire condition. |
| Combustion gases | Halogen acid-gas assessment and acidity/conductivity assessment under the applicable IEC 60754 parts. | A universal absence of hazardous combustion products. |
| Flame propagation | Performance in the specified single-cable or bunched-cable test. | Continued circuit operation while exposed to fire. |
| Declared fire class | An assessed reaction-to-fire classification for the documented product. | A class automatically assigned to every cable called N2XSH. |
المسؤول smoke-density test scope concerns smoke measurement under defined burning conditions. That evidence cannot substitute for an electrical circuit-integrity test. Emergency circuits with a specified survival time require the appropriate cable system and separate evidence.
N2XSH 12/20 kV Reference Dimensions
البيانات المرجعية الموصى بها. The table describes one published single-core copper construction with a copper wire screen. These dimensions and masses are not XWA guaranteed values or a confirmed supply range. Final cable data follows the approved manufacturing specification.
| Conductor/screen (مم²) | العزل (مم) | Over insulation (مم) | Minimum sheath (مم) | تقريبا. ل (مم) | تقريبا. كتلة (كجم/كم) |
|---|---|---|---|---|---|
| 1 س 95/16 | 5.5 | 24.0 | 2.1 | 36.0 | 1965 |
| 1 س 120/16 | 5.5 | 26.0 | 2.1 | 38.0 | 2235 |
| 1 س 150/25 | 5.5 | 27.0 | 2.1 | 39.0 | 2630 |
| 1 س 185/25 | 5.5 | 29.0 | 2.1 | 41.0 | 3035 |
| 1 س 240/25 | 5.5 | 31.0 | 2.1 | 43.0 | 3600 |
| 1 س 300/25 | 5.5 | 33.0 | 2.1 | 46.0 | 4220 |
| 1 س 400/35 | 5.5 | 36.0 | 2.1 | 49.0 | 5230 |
| 1 س 500/35 | 5.5 | 40.0 | 2.1 | 52.0 | 6290 |
Each row is for 12/20 كيلو فولت, maximum system voltage 24 كيلو فولت. The screen section follows the slash; 1×240/25 has one 240 mm² phase conductor and a separate 25 mm² screen. Values from 6/10 أو 18/30 kV designs are not interchangeable with this table.
No universal ampacity is assigned here. The current rating depends on circuit arrangement, ربط الشاشة, surrounding temperature, soil or duct conditions and neighbouring heat sources. A project calculation and the approved cable construction are required; conductor area or sheath designation alone is insufficient.
The Two Diameters That Matter at a Termination
An MV termination interfaces with several surfaces, not just a nominal conductor size. The diameter over insulation sets one accessory interface; the complete cable diameter sets another at the outer entry or seal. A termination range and a cable gland range therefore refer to different dimensions.
In the selected 240/25 reference, the insulation diameter is 31 mm while the complete cable diameter is approximately 43 مم. استخدام 43 mm to select an insulation interface confuses those surfaces. Manufacturing tolerances and the accessory’s own specified limits remain part of the fit assessment.
The semiconductive insulation screen also has its own preparation method. Strippable and bonded screen designs require the appropriate preparation procedure and tools. A cutaway illustration does not establish which removal method applies to the supplied cable.
Building Entry, Cable Trays and Protected Routes
Screened LSZH MV cables are relevant to industrial power distribution, substations and building feeders where the installation specification calls for controlled smoke and gas behaviour. A tunnel application requires the actual fire classification, route arrangement and local acceptance criteria; the word LSZH alone is not a tunnel approval.
An exterior-to-interior run can avoid an unnecessary sheath transition only when the same declared cable is suitable on both portions of the route. التعرض للأشعة فوق البنفسجية, standing water, soil contact and fire requirements must all be covered. Some published N2XSH designs restrict outdoor or underground use to protected installation, so direct burial is not a model-wide promise.
The copper screen is not impact armour. القنوات, يغطي, الصواني, supports or another protection system may be necessary where the route exposes the cable to damage. Water-blocking properties likewise require a specified design; a halogen-free sheath does not provide the longitudinal barriers identified by an (ف) البديل.
Cable routing remains constrained by the stated installation bend radius, pulling method and support system. The supporting explanation of نصف قطر انحناء الكابل MV وسحب التوتر separates these handling limits from the electrical rating.
N2XSH, N2XSY and N2XS2Y
| نموذج | Outer-sheath distinction | Relevant specification difference |
|---|---|---|
| N2XSH | Low-smoke, halogen-free sheath | Fire-test performance and installation suitability must be defined for the exact construction. |
| N2XSY cable | غمد PVC | PVC and LSZH have different combustion-gas and material characteristics. |
| N2XS2Y cable | غمد بي | PE sheath protection does not by itself imply a flame-retardant, low-smoke construction. |
| N2XS(ف)ح / N2XS(فلوريدا)ح | Halogen-free sheath with additional water barriers | (ف) identifies longitudinal water blocking; (فلوريدا) additionally identifies a radial moisture barrier in the specified design. |
The comparison concerns copper screened MV constructions. An aluminium-conductor NA2XSH design changes the phase-conductor material as well. Three-core N2XSEH places three screened phase cores inside a common sheath and needs its own dimensional and rating data.
Electrical Tests and Fire Evidence Have Different Jobs
اللجنة الانتخابية المستقلة 60502-2 addresses extruded-insulation power cables within its MV scope. عالية الدقة 622 / دين فد 0276-622 also appears in established halogen-free MV constructions. The agreed manufacturing standard and voltage designation must identify the actual design; listing several references does not establish simultaneous conformity.
مقاومة الموصل, insulation tests, partial-discharge assessment and oversheath tests relate to different electrical or material requirements. The applicable standard determines their method and acceptance limits. Routine production records are not interchangeable with a type-test report, and neither should be inferred from a product illustration.
For fire performance, the report or declaration must identify the assessed construction and the applicable method. A third-party catalogue’s class, certificate or laboratory accreditation cannot be carried over to another manufacturer. The product description here does not claim an XWA CPR class or circuit-survival rating.
N2XSH Cable Questions
Can N2XH replace medium-voltage N2XSH?
لا, not on sheath material alone. The MV construction described here includes electrical screens and voltage-specific insulation. A low-voltage N2XH cable does not become an MV cable because both designs use XLPE and a halogen-free sheath.
Does N2XSH automatically have a B2ca classification?
لا. A reaction-to-fire class belongs to an assessed product construction and its supporting documentation. The N2XSH designation alone does not assign B2ca or any smoke, droplet or acidity subclass.
ماذا يفعل 3 س 1 س 240/25 mean for this cable?
It describes three separate single-core cables, each with a 240 mm2 phase conductor and a 25 mm2 metallic screen. It is not one three-core cable under a common sheath. Phase arrangement and screen bonding still need their own design.
Is the copper wire screen mechanical armour?
لا. The metallic screen has electrical screening and specified earth-fault duties. It must not be treated as wire armour against impact or excavation damage. Mechanical protection follows the installation route and declared cable construction.
Related range: كابل الجهد المتوسط · أنواع ونماذج الكابلات
Related material comparison: PVC and halogen-free low-voltage sheath comparison. This supporting article concerns LV cables, not substitution for MV N2XSH.
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