12.7/22Kv 3 Core Copper Medium Voltage Cable

1. Identification of insulation material types: The thermal insulation performance of cables is usually closely related to their insulation materials. Common high thermal insulation materials include cross-linked polyethylene (XLPE), ethylene propylene rubber (EPR), polyvinyl chloride (PVC), etc. These materials are stable at high temperatures and have good thermal insulation effects.
Sheath material: The outer sheath material also affects the thermal insulation performance. For example, some cables use high-temperature resistant silicone rubber, fluoroplastics (such as FEP, PTFE) and other materials to provide better thermal insulation performance.

2. Temperature marking of temperature resistance grade: Generally, the outer sheath of the cable will be marked with a temperature resistance grade, such as 70°C, 90°C, 105°C, etc., which indicates that the cable can operate safely for a long time at this temperature. The higher the temperature resistance grade, the better the thermal insulation performance. Some cables will indicate the short-term extreme temperature resistance, such as 250°C, which can help determine its stability under short-term high temperature exposure.

3. Relevant standards and certifications: Cables that meet international standards are generally marked with their insulation and temperature resistance grades. These standards specify the performance requirements of cables under high temperature and load. Some cables carry fire resistance certifications, such as the UL fireproof mark or the IEC test pass mark. Such cables usually have excellent insulation and fire resistance.

4. Experimental test method: By placing the cable in a high temperature environment for a certain period of time, observing the physical changes and electrical performance changes of the insulation layer, if the cable can remain stable, its thermal insulation performance is good. Use professional equipment to test the thermal resistance coefficient of the cable. Cables with low thermal resistance coefficients can better isolate heat.

5. Insulation thickness: Cables with thicker insulation layers usually have higher thermal insulation performance. You can check the insulation thickness by consulting the cable specification or cutting the cross section. Some high thermal insulation cables use a multi-layer structure, such as an inner XLPE layer plus an outer PVC sheath, which can significantly enhance the thermal insulation effect.

6. Thermal conductivity of the material: Some thermal insulation materials have poor thermal conductivity, which helps to isolate heat. If the thermal conductivity of the insulation material is low (such as ceramic insulation or silicone), then its thermal insulation performance will be better.

7. Rated current carrying capacity: The current carrying capacity is related to the thermal insulation performance of the cable. Cables with good thermal insulation performance can maintain a lower external temperature at higher currents.