Precautions for installation of power cables: keep 2m distance when the cable is installed in parallel with the thermal pipe, and 0.5m should be maintained when crossing. The cable shall be installed at a distance of 0.5m in parallel or across other pipelines. When the cable is directly buried and installed, the buried depth of 1-35kv cable is not less than 0.7m. When 10KV and below cables are installed in parallel, the net distance between them shall not be less than 0.1m and 10-35kv shall not be less than 0.25m. The distance of cross installation is not less than 0.5m. Cable laying temperature is not lower than 0 ℃, bending radius: multi-core cable or 15 (D + D), a single cable 20 or more (D + D), (D for cable diameter, D) for the conductor diameter. 6 kv and above cable joint: (1) installing a cable terminal head, must be stripped semiconductor electric shielding layer, operation shall not damage the insulation, should avoid mark uneven situation, when necessary use sand paper to grind; The shield end should be flat and the graphite layer (carbon particles) should be cleaned. (2) plastic cable end copper tape screened and armor must be good grounding, the short circuit also follow this principle, avoid unbalanced three-phase run ShiGang armoured end produce inductive electromotive force, and even "lighter" and accidents such as burning sheath. It is required to use my tinplate to braid copper wire for grounding lead. When connecting with the cable copper belt, it should be welded with chromium-iron tin. The shield of three-phase copper tape should be connected with ground wire respectively. Note that the shielded ground wire and steel armor ground wire should be separately drawn out and insulated from each other. The position of the welded ground wire should be as low as possible. Basic requirements for cable terminals and intermediate joints: a. good conductor connection; B. The insulation is reliable, and it is recommended to use irradiated cross-linked heat-shrinkable silicone rubber insulation materials; C. good sealing; D. sufficient mechanical strength to meet various operating conditions. The end of the cable must be used to prevent erosion of water and other corrosive materials, so as to prevent breakdown due to the aging of the insulation layer caused by water trees. Crane or forklift should be used for the loading and unloading of cables. It is forbidden to run flat or lay flat. For installation of large cables, cable laying cart should be used to avoid external damage or abrasion caused by manual dragging. If the cable cannot be laid in time for some reason, it should be stored in a dry place to prevent sunlight from exploding and water entering the end of the cable. Note: the installation of wire and cable should be done by the installation personnel or full-time technical personnel familiar with the performance of wire and cable. If there are still unclear matters, please consult the relevant technical department or the technical department of our factory.
特种电缆就是有特殊用途、可以在特定场合使用的电缆，比如可以耐高温，耐酸碱，防白蚁，以及在轮船飞机核电站等场合使用的电线电缆。
就分类来说，它与电力、控制、计算机电缆等类别不属于同一种分类方法，也就是上列电缆中也包含有特种电缆在内。
一般特种电缆都需要制定企业内控标准。
航空航天、机车车辆、能源、钢铁、有色金属冶炼、石油开采、电机、建设等领域需用耐高温电线电缆。
长期连续工作温度135度、180度、250度及
有强电与弱电之分，这里介绍一种强电用低感电缆。
此电缆带有热耗散装置，用于各类接触焊机、电弧焊机与气动焊钳间相连接的新型水冷式低感电缆，具有结构简单合理、冷却水流通量大、不会形成堵塞阻断和限流现象、散热效果好、使用寿命长等特点。
型号、额定电压、名称及用途：型号额定电压（V）名称用途KVV450/750铜芯聚乙烯绝缘聚氯乙烯护套控制电缆敷设在室内、电缆沟、管道固定场合KVVP40/750铜芯聚氯乙烯绝缘聚氯乙烯护套编织屏蔽控制电缆敷设在室内、电缆沟、管道等要求屏蔽的固定场合KVVP2450/750铜芯聚。
绝缘材料：高密度聚乙烯。
绝缘单线：在导线上连续挤制绝缘材料，采用规定的10种标准色谱以便识别，并保证电缆的电气性能。
绝缘线对：将绝缘单线按规定的色谱、不同的节距均匀地绞合成线对。
缆芯结构：绝缘单线绞合成对后采用同芯式或单位式绞合成缆芯，各单位采用不同的扎纱，以便施工、维护识别。
一广场喷泉池中有C三组喷头。
该广场喷泉设计要求如下：喷泉的喷水规律是：当按下启动按钮，A喷头先喷5秒，再是C喷头喷8秒，B仍然喷4秒，接着C组喷头喷5秒，再接着C三组喷8秒，最后C三组停止1秒，之后循环之前的过程，直到按下停止按钮整个系统才会停止喷水。
该设计所用设备是三菱FX3U系列plc，该喷泉示意图如下：该喷泉的时序图如下：PLC的I/O分配表：编程方法一：利用比较指令直接输入大于小于等于符号编写实现设计要求。
25-50V、电流在“梅花芯“轮心“辐条