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8.1 The maximum long-term rated temperature allowed for the cable conductor during normal operation:
High-density polyethylene: 75°C; cross-linked polyethylene: 90°C.
8.2 The maximum allowable temperature of the cable conductor during short circuit (duration not exceeding 5 seconds) is: high-density polyethylene insulation: 150°C; cross-linked polyethylene insulation: 250°C.
8.3 The temperature of cable installation should not be lower than -20℃
8.4 Minimum bending radius for cable installation:
Single-core cable: not less than 20 times the outer diameter of the cable;
Multi-core cable: not less than 15 times the outer diameter of the cable.
8.510kV overhead insulated cables are widely used in urban and rural power grid construction and upgrades to replace traditional bare conductors, reduce the risk of electric shock, improve safety, meet urban beautification needs, avoid the impact of bare conductors on the landscape, and achieve the effect of "invisible power grid".
8.5.1 When installing light and thin-insulated cables overhead, a certain distance should be maintained from trees. When the cables are in operation, only short-term contact between the cables and trees is allowed.
8.5.2 When installing natural insulated cables overhead, a certain distance should be maintained from trees. When the cables are in operation, frequent contact between the cables and trees is allowed.
8.5.3 The remaining 10kV overhead insulated cables shall be installed in fixed overhead locations. A certain distance from trees shall be maintained during installation. Frequent contact between the cables and trees is permitted during operation. In addition, soft copper core overhead insulated cables shall be used as transformer downlead.
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