Frequently Asked Questions from TANO CABLE

1. Bare Conductor Overhead Cable is outside: it will be affected by climate and environmental conditions. Lightning, fog, wind, rain, snow, heat cold food, smoke and dust, fibers, etc are from different aspects threaten to Bare Conductor overhead Cables. 2.For the Bare Conductor Overhead Cable line fault phenomenon, there are mainly following situations mechanical damage, lead sheath cracking and spalling, head terminal flashover, head terminal or intermediate joints explode, insulation breakdown, metal sheath corrosion perforation and so on. For line fault causes of Bare Conductor Overhead Cable, there are following situations external damage, chemical etching or electroytic corrosion, lightning, flooding, pests and other natural disasters as well as the improper construction, improper maintenance etc. personnel negligence factors. 3. When lightning struck Bare Conductor Overhead Cable it has the potential to make insulator flashover or breakdown. In order to improve resistance capacity to lightning and prevent lightning accidents, we can install lightning wire or lightning rod to prevent the conductor directly struck by lightning. we can install tube arrester to prevent harm lightning invasion wave, we can configure automatic reclosing prevent lightning flashover or other discharge causing power outages; we also can install n the neutral point arc suppression coil, in order to reduce other risk of lightning or other causes or single-phase ground.

1. Cable insulation should be checked before laying cables, 6-10KV cable uses 2500V magneto-ohmmeter, telemetry insulation resistance 2100MΩ; 3KV and below cable uses 1000V magneto-ohmmeter, telemetry insulation resistance 250MΩ, the suspected cable insulation should be taken withstand voltage test before laying confirm eligibility. 2. We should pay attention to the winding direction of the cable when erecting cable tray, should pull the cable from the top of cable tray, to prevent loose cable when cable tray is rotated. Pulled cable should be hold on rolling shelves or hold by people, not rub on the ground or gallows. 3. When laying cable, its curvature shall not less than the minimum allowable bend radius. At the end. persons who pull the cable should stand in the opposite direction of cable. 4. High voltage cables, low voltage cables and control cables should be separated laying. they arranged sequentially from top to bottom is high voltage cables, low voltage cables and control cables. Cross intersection should be arranged at the bottom of the cable or the inside, so that the exposed parts in order. 5. When cable laying, cable end termination and connector can leave spare length, and cable should be left at a small margin of the entire length when laying underground cable, and for undulating (snake) shape laying. 6. After the cable laying we should hang signboard in time, at both ends of the cable intersection, the corner point, entrance and exits of buildings all should be hang signboard. 7.Cable hardens in winter so that insulation is vulnerable to damage when laying cable. Thus, if the cable is laid prior to placement at the temperature below 0~5℃, the cable should be preheated. There are two methods of preheating: 1)Increase the ambient temperature around the cable It will take three days and nights when the room temperature is 5- 10℃, one day and night at 25℃. and 18 hours at 40℃. Preheated cable should be completed laying within 1 hour. 2)Energized cables make the cable itself fever. Heating time is short with this method, but we should pay attention the applied current should not exceed the allowable cable ampacity. Cable surface temperature should not be higher than 40℃, not less than 5℃. 8.When cutting the cable, it should be based on the location of device terminals, and to consider maintenance moisture and other needs, determine the location of the fracture cable. To prevent loosening both sides will be tied up before sawing with iron wire and after sawing cable should be sealed immediately.