Precautions for heating shrinkage of heat shrinkable tubes and installation requirements for power cable accessories

1. All heat shrinkable tubes are made of polymer materials by special process, when the temperature reaches 110℃-130℃, the material begins to shrink and the shrinkage is greater than 50%. The material will not be affected for a short period of 140 ℃, but local long periods of high temperature overheating will damage or even burn the material, affecting the material properties.

2. Heating tools recommended the use of propane spray gun, flame yellow temperature moderate, heating area is large, the use of gasoline blue flame temperature is high, should pay attention to appropriate away from the material, control temperature, avoid burning.

3. In order to ensure the close bonding and bonding strength between the heat shrinkable pipe and the coating material, the coating area and the Bonding seal section should be preheated before each layer of pipe fittings, and then cleaned with cable cleaning paper. Remove the flame smoke charcoal sediment, so that the contact between the layers is good.

4. When the pipe begins to shrink, the flame is slowly approaching, moving around it to ensure a uniform radial shrinkage, and then slowly extending the heat shrinkage pipe extension, the flame toward the shrinkage direction, to preheat the pipe, conducive to uniform shrinkage. Following the starting shrinkage and direction recommended in the installer, shrinkage from the bottom is beneficial to the removal of gas and enhanced sealing.

5. The finished pipe with shrinkage should be smooth and wrinkle-free, and the original structure contour can be clearly seen. A small amount of sealant extrusion at the sealing site indicates a complete seal.

Thermal shrinkage Power cable accessories are divided into outdoor terminal, indoor terminal and intermediate connection, outdoor terminal refers to the open-air cable connector, the indoor terminal refers to the connection between the cable and electrical equipment, the intermediate connection is divided into two-way and transition type. Two cables of the same type of insulating structure are connected to each other as straight-through, and two cables with different insulation structure types are connected to each other as transitions. Here are a few hot shrinkage power cable Accessories installation conditions and requirements:

1. Thermal shrinkage accessories should be installed at ambient temperature of more than 0 ℃, relative humidity of less than 70%. Avoid insulating surface condensation moisture, low ambient temperature, humidity should take remedial measures.

2. The hot shrinkage Intermediate connection head is not allowed to move the cable when it is not fully cooled.

3. During the construction process, damage to cable sheath and insulation is strictly prohibited.

4. Thermal shrinkage Accessories contact with metal parts sealed parts (such as lead bags, terminals) should be carefully punched and cleaned with a cleaning agent.

5. In place at the end of the cable, the line core staggered should be avoided so as not to affect the sealing effect.

6. Do not cut the heat shrinkable tube at will.

7. Can not be constructed in the fog weather, found that the cable into the water, damp, should take remedial measures.

At present, the thermal shrinkage cable accessories have been rapidly popularized and widely used. Thermal shrinkage Cable terminal head and cable Middle head production quality is particularly important. First of all, there are strict requirements for cleaning work. Production has a better environment of high-temperature heat shrinkable pipe site, at the same time in the production process of each process to be clean with anhydrous alcohol, especially in the welded ground after the three-fork mouth, but also carefully clean the remaining solder slag and the use of spray lamp left behind the carbon, in addition to pay attention to the operation, do not wear impurities of unclean gloves If the day hot sweat more attention, so as to avoid the hands and face of the sweat contaminated to the cable accessories, to ensure that the production process of each process is kept clean.

热缩管加热收缩注意事项及电力电缆附件安装要求

1．所有热缩管均系高分子材料经特殊工艺制作，温度达到110℃—130℃时材料开始收缩，收缩率大于50％。材料在140℃短时间将不受影响，但局部长时间高温过热将损伤甚至烧毁材料，影响材料性能。

2．加热工具推荐使用丙烷喷枪，火焰呈黄色温度适中，加热区域大，使用汽油蓝色火焰温度高，应注意适当远离材料，控制温度，避免烧焦。

3．为确保热缩管和包敷材料间的紧密结合和粘接强度，套入每层管件前，被包敷部位和粘接密封段应预热，随后用电缆清洁纸清洗。去除火焰烟炭沉积物，使层间接触良好。

4．开始收缩管件时火焰要缓慢的接近，在其周围移动确保径向收缩均匀，再缓慢延热缩管伸，火焰朝收缩方向，以预热管材，有利于收缩均匀。遵循安装程序中推荐的起始收缩部位和方向，由下往上收缩有利于排除气体和增强密封。

5．收缩完毕的管件应光滑无折皱，能清晰看出其原有的结构轮廓。密封部位有少量密封胶挤出表明密封完善。

热缩电力电缆附件分户外终端、户内终端和中间连接，户外终端是指露天电缆接头，户内终端是指电缆与电气设备的连接；中间连接分为直通式和过渡式两种．两根绝缘结构类型相同的电缆相互连接为直通式，两根绝缘结构类型不同的电缆相互连接为过渡式。下面讲几点热缩电力电缆附件安装条件及要求：

1.热收缩附件的安装应在环境温度0℃以上，相对湿度70％以下。避免绝缘表面结露受潮，环境温度偏低、湿度过大时应采取补救措施。

2.热缩中间连接头在没有完全冷却时，不准移动电缆。

3.施工过程中，严禁损伤电缆护套和绝缘。

4.热收缩附件与金属部件接触密封的部位(如铅包、端子)要仔细打毛并用清洗剂清洗干净。

5.在电缆端就位处，应避免线芯错动，以免影响密封效果。

6.不要随意切割热缩管。

7.不能在雨雾天气中施工，发现电缆进水、受潮，应采取补救措施。

目前热缩电缆附件得到了迅速推广和广泛应用。热缩电缆终端头和电缆中间头制作质量尤为重要。首先对清洁工作有严格要求。制作时有环境较好的高温热缩管场地，同时在制作过程中的每一道工序完成后都要用无水酒精清洁，尤其是在焊接地线后的三叉口处，更应认真地清洁余留的焊渣及使用喷灯后留下的积炭，另外也要注意操作，不要戴有杂质的不干净手套，如天热流汗更要注意，以免手及脸上的汗水沾染到电缆附件上，确保制作过程的每道工序都保持清洁。

注意以上清洁工作的原因所在是：电缆头制作过程中往往是露天作业，空气中的有害尘埃，极易沾染到热缩电缆附件及电缆的半导体及绝缘层上。在焊接地线、剥切半导体层或使用喷灯时留下的积炭等。如果制作过程中不注意清洁工作，会造成尘埃和积炭与热缩件结合在一起，从而造成电缆附件界面爬行放电，导致纵向击穿电缆绝缘。