Since it is to be used as an insulating material, the insulating tube must be flame-retardant, but the quality of the insulating tube on the market is uneven, in order to prevent the purchase of counterfeit products, we must learn to distinguish the real insulation tube. You can use a lighter to burn the insulation tube. If it extinguishes when you remove the fire source, it will certainly be flame-retardant.
In addition to purchasing a real insulation tube, we must learn to use it properly. If all the wires that should be put in two insulating tubes are put in a sleeve, although many materials can be saved, the wires in the sleeve are too large. First of all, the heat generated when using high-power electrical appliances may burn the wire insulation skin, there is a safety hazard; secondly, the wires inside the casing are too crowded, and if the wires need to be repaired at a later date, they cannot be pulled out.
In the process of circuit reconstruction, it was found that the wires buried in the wall were all put in the insulating tube, but the number of wires that can be worn in each casing is not necessarily known. In general, lighting and sockets are separate, easy to control and repair, and their wire diameters are also different. However, sometimes there is a need to install a very small wattage wall lighting near the outlet. It is also a good idea to take electricity from this outlet, which can save money and simplify the circuit.
As a kind of insulating material, the insulating sleeve includes glass fiber insulating sleeve, PVC sleeve, heat shrinkable sleeve, and so on. The single insulation tube is made of pure porcelain or resin insulation and is used for voltage levels of 35 kV and below; its insulation is tubular, and the middle is fitted or glued to fix it on the perforated wall.
In addition, the insulation structure of a single insulation sleeve is divided into two types: air cavity and air cavity short-circuit type, wherein the air cavity sleeve is used for voltage levels of 10kV and below, and an air cavity is provided between the conductor and the porcelain sleeve as auxiliary insulation, and the sleeve capacitance can be reduced, increasing the corona voltage and the sliding voltage of the tube.
However, when the actual voltage level is high, a corona will occur inside the air cavity of a single insulating sleeve and the above-mentioned effect will be lost. In this case, an air cavity short circuit structure is adopted. The ceramic sleeve of the porcelain sleeve is coated with a semiconductor glaze on the inner wall, and the spring is connected to the conductor to short the air chamber to eliminate the internal corona and improve the discharge characteristics of the bushing.