常用的电线、电缆按用途分有哪些种类？ 答：按用途可分为裸导线、绝缘电线、耐热电线、屏蔽电线、电力电缆、控制电缆、通信电缆、射频电缆等。 2、绝缘电线有哪几种？ 答：常有的绝缘电线有以下几种：聚氯乙烯绝缘电线、聚氯乙烯绝缘软线、丁腈聚氯乙烯混合物绝缘软线、橡皮绝缘电线、农用地下直埋铝芯塑料绝缘电线、橡皮绝缘棉纱纺织软线、聚氯乙烯绝缘尼龙护套电线、电力和照明用聚氯乙烯绝缘软线等。 3、电缆桥架适合于何种场合？ 答：电缆桥架适用于一般工矿企业室内外架空敷设电力电缆、控制电缆，亦可用于电信、广播电视等部门在室内外架设。 4、电缆附件有哪些？ 答：常用的电附件有电缆终端接线盒、电缆中间接线盒、连接管及接线端子、钢板接线槽、电缆桥架等。 5、什么叫电缆中间接头？ 答：连接电缆与电缆的导体、绝缘屏蔽层和保护层，以使电缆线路连接的装置，称为电缆中间接头。 6、什么叫电气主接线？ 答：电气主接线是发电厂、变电所中主要电气设备和母线的连接方式，包括主母线和厂用电系统按一定的功能要求的连接方式。 7、在选择电力电缆的截面时，应遵照哪些规定？ 答：电力电缆的选择应遵照以下原则： （1）电缆的额定电压要大于或等于安装点供电系统的额定电压； （2）电缆持续容许电流应等于或大于供电负载的最大持续电流； （3）线芯截面要满足供电系统短路时的稳定性的要求； （4）根据电缆长度验算电压降是否符合要求； （5）线路末端的最小短路电流应能使保护装置可靠的动作。 Commonly used what types of wire and cable according to utility cent? Answer: according to the application can be divided into bare wire, insulated wire, heat-resistant wires, shielded wires, power cables, control cables, communication cables, rf cables and so on. 2, what kind of insulated wire are there? Answer: often the insulated wire has the following kinds: PVC insulated wire, PVC insulated flexible wire, nitrile soft PVC compounds insulation wire, rubber insulated wire, agricultural underground buried plastic insulation aluminum core wire, rubber insulation cotton textile soft wire, PVC insulated nylon sheathed wire, electric power and lighting soft PVC insulated wire and so on. 3, cable tray is suitable for the occasion? Answer: cable bridge is applicable to general industrial and mining enterprises inside and outside aerial power cable, control cable laying, can also be used in telecommunications, broadcasting and television and other departments in the indoor and outdoor set up. 4, cable accessories have? Answer: the commonly used electrical accessories have cable terminal connector, cable junction box, connecting the middle tube and terminal blocks, wiring trough, cable tray of the steel plate, etc. 5, what is joint between the cable? Answer: the connecting cable and the cable conductor, insulation shielding layer and protective layer, so that the cable line connection device, called a cable joint in the middle. 6, what is the main electrical wiring? A: the main electrical wiring is the main electrical equipment in power plant, substation and busbar connection mode, including the mistress line and auxiliary power system in a certain function requirements of connection mode. 7, in the choice of power cable section, should follow the rules? A: the choice of power cable shall comply with the following principles: (1) the rated voltage of the cable to be greater than or equal to the rated voltage of the power supply system installation points; (2) the cable continuous permissible current should be equal to or greater than the maximum continuous current of the power supply load; (3) wire core section to meet the requirements of the stability of power system short circuit when; (4) according to the cable length calculation is in line with the requirements of the voltage drop; (5) the line at the end of the minimum short circuit current should be able to make reliable protection device.