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1. Scope and Application 

**NF C33-225** applies to **power cables and their accessories** specifically designed for aerodrome lighting systems. These cables are part of the primary circuit that connects the power source to transformers and lighting fixtures, such as runway and taxiway lights.

Key Characteristics: 

• Rated Voltage: 6/10 kV (U₀/U) with a maximum system voltage (Uₘ) of 12 kV.
• Environment of Use: Suitable for installation underground, in ducts, or directly buried, with high resistance to environmental stresses.
• Safety Standards: Ensures reliability in critical aerodrome operations, complying with international safety requirements.

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2. Construction of NF C33-225 Cables 

Cables designed under NF C33-225 must meet stringent requirements to ensure performance and safety in demanding environments:

1. Conductor: 
- **Material:** Typically made of annealed copper or aluminum for optimal conductivity. 
- **Design:** Stranded conductors for flexibility and durability.

2. Insulation: 
- **Material:** Cross-linked polyethylene (**XLPE**) or ethylene propylene rubber (**EPR**) for excellent electrical and thermal performance. 
- **Voltage Rating:** Insulation must withstand up to 12 kV for safety and reliability.

3. Screen: 
- Metallic or semi-conductive layers applied around the insulation to minimize electromagnetic interference (EMI) and ensure even electric field distribution.

4. Outer Sheath: 
- **Material:** Halogen-free, flame-retardant thermoplastic compounds, such as polyethylene or PVC. 
- **Protection:** Designed to resist moisture, abrasion, and mechanical stresses.

5. Additional Features: 
- High resistance to UV radiation, oils, and other environmental factors. 
- Capable of withstanding high temperatures typically encountered in aerodrome applications.

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3. Key Features of NF C33-225 Cables 

1. High Voltage Handling: 
- Rated for systems with a nominal voltage of **6/10 kV** and capable of handling transient overvoltage up to **12 kV**.

2. Environmental Resistance: 
- Designed for harsh environments, including exposure to moisture, chemicals, and extreme temperatures.

3. Fire Safety: 
- Flame-retardant materials reduce fire risks in underground and confined installations.

4. Longevity and Durability: 
- High-quality materials ensure a long service life and minimal maintenance requirements.

5. Operational Reliability: 
- Ensures consistent power delivery to critical aerodrome lighting systems, reducing the risk of outages.

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4. Applications of NF C33-225 Cables 

Cables specified under **NF C33-225** are used in the primary circuits of aerodrome lighting systems. These applications include:

• Runway Lighting: Powering approach, threshold, and edge lights.
• Taxiway Lighting: Supplying lighting systems for taxiways and parking aprons.
• Apron Lighting: Ensuring proper illumination for aircraft handling areas.
• Navigation Aids: Providing power to navigational lighting and visual guidance systems.

Example Use Case: 
NF C33-225 cables connect a **6 kV power source** to series transformers that distribute power to runway edge lights, ensuring continuous and reliable operation in all weather conditions.

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5. Advantages of NF C33-225 Cables 

1. Safety and Reliability: 
- Maintains performance under high electrical stress and harsh environmental conditions.

2. Fire Resistance: 
- Reduces risks associated with fire, critical for underground and aerodrome installations.

3. EMI Protection: 
- Screened design ensures minimal electromagnetic interference, maintaining signal integrity.

4. Long Service Life: 
- Durable materials provide a long operational lifespan, minimizing maintenance and replacement costs.

5. Compliance with Standards: 
- Meets international and French standards for power cables, ensuring global applicability.

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6. Testing and Compliance Requirements 

To comply with **NF C33-225**, cables must undergo rigorous testing:

1. Electrical Testing: 
- **Voltage Withstand Test:** Ensures insulation can handle overvoltage conditions. 
- **Insulation Resistance:** Confirms low leakage currents. 

2. Mechanical Testing: 
- **Abrasion Resistance:** Evaluates the durability of the outer sheath. 
- **Tensile Strength:** Verifies the mechanical robustness of the cable. 

3. Fire Performance Testing: 
- Flame propagation tests in accordance with IEC 60332 standards. 
- Smoke density tests (e.g., EN 61034) to ensure low smoke emission. 

4. Environmental Testing: 
- **Moisture Resistance:** Validates performance in wet environments. 
- **UV Resistance:** Ensures longevity in outdoor installations.

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7. Compliance with Related Standards 

Cables compliant with **NF C33-225** align with related standards for power cables and aerodrome systems:

 

Standard	Purpose
IEC 60502-2	High-voltage cables for power distribution.
EN 50397-1	Cables for overhead and aerial systems.
IEC 60332	Fire performance and flame retardancy tests.
NF C33-226	Accessories for aerodrome lighting cables.

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8. Conclusion 

**NF C33-225** specifies the technical requirements for **insulated cables** used in **aerodrome lighting primary circuits**, ensuring high performance, reliability, and safety in critical aviation infrastructure. These cables play a vital role in maintaining the operational integrity of airport lighting systems.

Key Takeaway: 
NF C33-225 cables are designed to withstand high voltages, environmental stresses, and fire hazards, making them indispensable for modern aerodrome systems.

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