The temperature characteristics of power cables vary depending on the cable type and insulation material, covering the following aspects:
Rated Operating Temperature:
- Standard XLPE-insulated cables: 90°C
- PVC-insulated cables: 70°C
- Fluoroplastic-insulated, silicone rubber-sheathed cables: 180°C
- Fluoroplastic-insulated and sheathed cables: 200°C
- CE low-temperature power cables: 120°C
Short-Circuit Temperature:
- For most power cables, the conductor temperature during a short circuit (duration not exceeding 5 seconds) does not exceed 250°C
- For certain special cables, such as flame-retardant power cables, the short-circuit temperature is 160°C
Installation Temperature:
- Generally, the ambient temperature during cable installation should not be lower than 0°C
- High-temperature resistant cables can be installed at temperatures as low as -15°C
- Special low-temperature power cables can be used in environments as cold as -60°C
Aging Characteristics:
- Cable lifespan is influenced by temperature and follows the Arrhenius curve
- The rated lifespan of PVC cables is approximately 20 years
- Increased temperatures accelerate cable aging and reduce service life
Ambient Temperature Effects:
- Current-carrying capacity requires adjustment via correction factors based on ambient temperature
- For installation in air, the correction factor is 1.00 at an ambient temperature of 40°C
- For direct burial, the correction factor is 1.00 at a soil temperature of 25°C
Emergency Load Characteristics:
- Cables can withstand emergency loads exceeding the rated temperature for short periods
- Overload protection requirements differ across standards (ANSI/IEEE vs. CENELEC/IEC)
Bending Radius Requirements:
- Single-core cables: Generally 15–20 times the cable's outer diameter
- Multi-core cables: Generally 10–15 times the cable's outer diameter