Prefabricated and cold-shrinkable cable accessories are made of silicon image adhesive with good material characteristics such as high elasticity, high resistance volume ratio, good hydrophobicity and good aging resistance.
The raw materials used in these two accessories are basically the same, but the different production and installation process and design principle make the two cable accessories reflect different characteristics.
Let's start with prefab:
Advantages: the production process is relatively simple due to no pre-expansion, high productivity;
Small volume, simple installation process, simple installation and operation, and no fire, save time and effort, greatly reduce the quality accident caused by improper operation, low possibility of installation error;
Disadvantages: due to the limitations of precast technology brings a series of problems, the inner diameter of the prefabricated type terminal is only slightly less than the outer diameter of cable insulation layer makes the terminal to the smaller radial pressure produced by the cable to cable respiration is not obvious, sealing is relatively weak, it's easy to have a gap which can lead to happen because of the possibility of creepage flashover greatly increase (of course this does not mean that unsafe prefabricated cable accessories, please don't be taken out of context, is only relative to the cold type it in this lower safety coefficient).
The small radial pressure of the terminal on the cable will also appear in the terminal positioning is not strong. It is easy to appear because of the dislocation in the process of moving the cable (such as helping the pole on the cable), which leads to the stress cone deviating from the copper shielding section and does not work to break down the accident.
The cold type:
Advantages: Applicable surface width, a specification for three square cable;
After installation, the appropriate radial pressure is always maintained on the cable body, so that the inner interface is tightly combined, and electric breakdown will not be caused by the breathing action of the cable during operation.
Easy installation and operation, no fire, save time and effort, solve the shrinkage of prefabricated cable accessories or not to install in the phenomenon.
The sealing is good in the environment of high humidity and heat, high salt spray operation safety is good.
Disadvantages: due to the production process of an expansion process and due to the need for expansion and contraction characteristics, the cold shrinkable cable accessories used by the silica gel than the prefabricated performance is much higher (such as tensile strength and tear resistance, etc.) so that the production cost is higher than the prefabricated accessories;
The storage period is short, usually half a year to two years, because the cold-shrinkable cable accessories are pre-expanded. If the inner brace is stored for a long time, the brace may be scattered or the fatigue contraction of the silica gel material is not in place.
(so cold cable accessories are generally using high performance liquid silicone production, now there are some cheaper cold cable accessories use solid silica gel production performance is much worse, aging fast prone to cracking, the phenomenon of contraction is not tight, the advantages of using solid silica gel production cold type attachments will soon disappear.
Suggest that we don't keen on gaining petty advantages when cold cable accessories of choose and buy, try to choose those imported liquid silicone production cable accessories manufacturers products, such as the United States dow corning liquid silicone should be regarded as the best) relative to prefabricated type, installed the cold cable accessories for workers of some higher requirements, installation is relatively complex.
To the city for a cold type prefabricated cable accessories, shrinkage cable accessories based design based on prefabricated type attachment evolved thanks to the progress of silicone materials (because of the cold type attachment using silicone material performance requirements is very high, prefabricated type attachment arises silicone material performance can not meet the requirements of current cold attachment).
The design concept of cold-shrinkable cable accessories is more advanced, and it has the tendency to replace prefabricated cable accessories.