In the winter, with the sudden drop in temperature, the wire and cable industry has been affected. The most obvious effect is that the difficulty in laying cables has increased. For example, it is known that oil viscosity of a viscous oil-impregnated paper-insulated cable increases at a low temperature, and that a laying man is liable to damage the insulation, and the impregnant without a trickle cable has a large viscosity, and the low-temperature laying has a greater influence on the same. Under such circumstances, how should we proceed with cable laying in the winter and how can we make full preparations to avoid unnecessary losses?
Before the cable is laid, it must be fully prepared. Before the winter construction arrives, relevant construction personnel shall be organized to learn construction measures and preventive measures, and familiar with the construction drawings and technical documents concerning the laying of cables. It also established a strict winter construction management system, strictly implemented the winter construction procedures and specifications, and formulated construction and preventive measures to ensure that people, machines, materials, and materials will survive the winter and ensure that project quality and project progress are not affected. Then according to the established construction measures and preventive measures, do a good job in the material plan. The materials department should do a good job of supplying the required materials according to the plan, including insulation materials, anti-freezing, cold protection, anti-skid, heating materials, etc. Material needed for the facility. And ensure the smooth construction of roads, ice and snow in a timely manner, the surface is frozen.
Secondly, in the process of laying cables, we must always pay attention and always be prepared. For example, due to low temperatures in winter, when there is enough snow accumulation, if the cable is a hard conductor. Not easily twisted, snow will fall off the wire automatically. At the same time, due to the different density of hard cables, when the snow gradually solidifies to the ice, it will automatically crack when it reaches a certain level, causing customers to misunderstand, so the appearance is easy to cover snow and ice. When the weight of the ice layer exceeds the capacity of the wire and cable, due to the wire and cable overhead is outdoors. It is easy to cause the cable to pull the power transmission tower or pull the power pole and the cable itself collapses. Then, in order to prevent this from happening, the choice of data should be carefully selected to withstand the cold cables.
Thirdly, if the outdoor work is performed at temperatures below -5°C, a heating lounge should be set up near the construction site. The heating facilities should meet the fire prevention regulations. The construction heating and heating facilities must have obvious signs to prevent people from getting burned.
Fourth, when the ambient temperature of the cable storage site is lower than the service condition of the cable, do not put the cable, and wait until the cable is stored in a warm place for 24 hours before laying.
Fifth, before the cable is pulled, it is necessary to carefully check whether the code, specification, length, name and location of the end-point device of the cable are consistent with the cable list and drawing, and check whether the cable is damaged. Sixth, when cables of different jackets are mixed and pulled, special attention should be paid to prevent the cables from rubbing against each other and damaging the cable jacket.
Seventh, after each cable is drawn, it is necessary to level the cable, correct the length of the cable, and hang the cable around the device. Do not throw the cable anywhere and step on it to avoid damaging the cable.
Eighth, after all the cables have been applied, the model, specifications, and the length and total number of access equipment should be fully checked to prevent mistakes or omissions. Only after correcting the cables can the cables be sturdy. If the rigging process is used to sturdy the cable, it can be sturdy with a cable tie after the cable has been pulled and the cable is rechecked and then the second bundle is pulled. In the end, strict compliance with the safety technology in the winter season and good visa records.
In addition, special precautions should be taken in the installation of cable installations, and attention is always paid to the safety of laying. For example, when laying cables, the ambient temperature shall not be lower than the following as per the "Guidelines for Construction and Acceptance of Industrial Automation Instrumentation Projects (Standards)" GB/50093-2002 (GBJ93-86): 1. Cross-linked polyethylene cable 0 °C; 2. Low pressure Plastic wire -20 °C; 3 rubber and PVC sleeve rubber insulated cable -15 °C. If the above conditions are not met, the constructor will take the entire cable to a room with sufficient space for preheating, and the room temperature is guaranteed to be around 25°C. After the temperature of the cable reaches and exceeds the specified temperature, rapid lay-up of the installation work shall be carried out. The laying time shall not be too long and shall be controlled within 4 hours. The ideal time shall be from 10:00 am to 23:00 in the morning.
Another way is through the current heating method, that is, the cable core into the current, so that the cable itself is heated, this method of heating, quick, can quickly heat the cable insulation to the desired temperature in a short period of time. However, the current-through heating method has specific requirements for different cable heating times. For example, a 3 x 16 mm cable with a maximum allowable current of 102 A is heated at 0 degrees for 56 minutes; at a temperature of minus 10 degrees, it is heated for 73 minutes at minus 20 degrees. Heat 74 minutes. A 3 x 25 mm cable with a maximum allowable current of 130 A was heated for 71 minutes at 0 degrees; it was heated for 88 minutes at minus 10 degrees and heated for 106 minutes at minus 20 degrees. A cable of 3 x 35 mm with a maximum allowable current of 160 A is heated at 0 degrees for 74 minutes; at a temperature of minus 10 degrees for 93 minutes, it is heated at minus 20 degrees for 112 minutes. Cables with 3 x 50 mm maximum allowable current of 190 A are heated for 90 minutes at 0 degrees; 112 minutes for heating at 10 degrees below zero, and 134 minutes for heating at minus 20 degrees... In addition, cable laying should not be performed in the morning or at night. Sub-periodic construction to ensure that the cable does not break, no cracks and other phenomena. In addition, various equipment and instruments should have antifreeze and constant temperature facilities to ensure their accuracy. Thirdly, construction workers should be dressed and kept warm, their soles should be soft, non-slip and insulated to prevent falls and frostbite. Gloves should be worn for outdoor operations. Hand irons should not be held by hand. Fourth, strengthen winter production safety management, enhance winter production safety awareness, strengthen the publicity, education, and training of winter construction knowledge, and improve the workers' self-prevention awareness and safe operation skills.
In general, cable routing is generally not encouraged or even allowed at very low temperatures. Especially in northern China, the temperature is lower in winter. Therefore, in addition to the necessary accident maintenance, cable laying works should be avoided as much as possible. In addition, as modern buildings become more advanced, they also impose higher requirements on the laying of cables in winter. It is necessary to conduct research from the perspectives of reducing construction costs and improving the efficiency of laying work, so as to improve the comprehensive competitiveness of wire and cable manufacturers.
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