What Degree Celsius Should Be Used For The Insulation Level Of Wires In Rural Lighting Ready Boards In Africa? Adapting To The Rural Environment In Africa?
Selection of Insulation Grade for Wires in African Rural Lighting ready boards
Most rural areas in Africa are installed outdoors or semi outdoors in tropical regions. The box is exposed to direct sunlight, and the temperature inside the box can be 10-15 ℃ higher than the ambient temperature. Extreme temperatures inside the box can reach 60-65 ℃. Ordinary 70 ℃ PVC wires have insufficient temperature margin, and the insulation is prone to accelerated aging and cracking. Therefore, it is not recommended as the main choice. The wiring inside the lighting Ready Board Box should preferably use insulation grade wires (XLPE cross-linked polyethylene or heat-resistant 90 ℃ modified PVC, in accordance with IEC60227 and IEC60502 standards) with a long-term allowable working temperature of 90 ℃; High temperature desert exposed areas can upgrade to 105 ℃ heat-resistant insulated wires, balancing overload temperature rise and environmental heat accumulation.
70 ℃ ordinary PVC can only be used for local auxiliary circuits with complete shading and good ventilation in the lighting ready board body, and must be used with reduced capacity. It is not recommended to use it in bulk for large-scale projects. The 90 ℃ grade wire can safely operate at 90 ℃ for a long time, withstand high temperatures of 250 ℃ for 5 seconds after short circuit, and has sufficient temperature margin to resist the combined effects of sunlight heating and current carrying heating of the wire, delay insulation thermal aging, and adapt to the high temperature, high ultraviolet radiation, and large temperature difference between day and night in Africa.
The voltage level is selected as 450/750V, and the conductor is given priority to tin plated copper core to enhance the antioxidant capacity in humid and dusty environments. The outer sheath should have anti UV and anti mold properties to slow down outdoor photo oxidative aging. The selection should take into account temperature reduction calculation. When the heat dissipation inside the box is poor, the current carrying capacity of the wire should be multiplied by a coefficient of 0.8-0.85 according to the standard value to avoid the actual operating temperature approaching the insulation limit, reduce leakage and short circuit faults, improve the service life of the distribution system, and meet the long-term low maintenance needs of rural areas in Africa.
