Detailed knowledge of insulation supplies

What is the difference between insulated boots and ordinary boots and shoes?
Insulation boots, shoes, shoes and boots are different in design. Insulation boots and shoes are made of insulating rubber material in the structural design. The insulation layer forms a closed insulation system to protect the foot. The ordinary boots and shoes are different. The ordinary soles and the soles of the shoes and sponges are not used as insulating materials, and the insulation performance is very low and electric leakage is easy. Some leakage currents as high as 30mA far exceeds the safety current. Insulation boots only conduct electrical performance tests and can only be delivered after passing the inspection. Normal boots do not have this requirement.

Why should insulation protection wear dry?

The use of insulating protective equipment in a dry state is a big problem that the user must pay attention to, because if the insulating protective equipment contains a certain amount of moisture, the volume resistance and the surface resistance of the insulator are greatly reduced. Water is a conductor. Due to the presence of water, the insulating properties of the insulator are greatly reduced or even destroyed. Because the atomic constitution angle of water ∠ HOH=105° has strong polar properties to generate ion conduction, many impurities in one water can undergo chemical changes under the action of heat, light, and electricity to generate electric conductors and destroy insulation properties. Maintaining the dryness of the insulating protective equipment can greatly improve the safety performance.

What is the most important indicator of the insulation performance of insulating protective equipment?

Insulation protective equipment (insulated boots, shoes, gloves, etc.) wear to prevent electric shock is mainly caused by the human body through the current, so the protective performance of the insulator is mainly depends on the size of the leakage current through a certain voltage, if The leakage current is safe within the safe current value range, otherwise it is not safe. If a certain voltage is applied, although no breakdown is caused, excessive leakage current also causes human injury.

Insulation protective equipment Why do preventive tests?

Conducting preventive tests is a strict provision of the power industry that guarantees the safety of the person. Some insulation protection products have a long three-guarantee period. In such a long period of time, because of aging or changes in storage and other conditions, it is necessary for users to conduct preventive tests before use. Insulative boot shoes can also be used for preventive testing if they exceed the three packs.

What is the relationship between the test voltage and the maximum range of use?

Insulation protective equipment before leaving the factory, one by one under a certain AC power frequency voltage test, for example, the use of 5KV is the line voltage 380V. The test voltage is a safety factor of 13.2 times the voltage used, but the conditions and environments of use vary, and countries vary. Use the empirical formula of the United States to determine the relationship between the test voltage and the maximum range of use. According to the recommended empirical formula of US ASDTMD120-79: maximum voltage = test voltage × 0.95-2000V

What should I pay attention to when wearing anti-static protective equipment and wearing anti-static protective equipment?

The environment to be protected against static electricity is mainly to prevent electrostatic charge caused by the flow of charges caused by friction to cause electrostatic induction, or to cause harm caused by electrostatic discharge by high voltage. After wearing the anti-static protection product, the accumulated charge can be grounded through the anti-static product in time, and underwear and socks made of raw materials such as fur cannot be worn at the same time because they are insulated and prevent the human body from being conductively grounded. (The resistance value of conductive shoes is not more than 100KΩ-1000KΩ).

What is the safe current the human body can withstand?

The insulation resistance value of the human body is 800-1000 ohms, but this is different from the person's fatness and thinness, the thickness of the skin, the size of the age, the height of the individual, and is different from the physical strength of the person. The United States' safety current standard frequency AC is 16mA, and our current standard is 14mA. Under normal circumstances, the human body in the frequency of AC 1mA or DC 5mA human body has a feeling of hemp, in the following frequency AC 14mA can get rid of the power supply, if the AC power frequency current 20-25mA DC 80mA human body caused by numbness or severe pain, or Difficulties in breathing, unable to get rid of currents, may result in life-threatening risks over time.

After wearing insulating boots, what should you watch out for when working?

During electrical work, insulation boots should be used for insulation protection according to the regulations. However, sometimes the labor intensity is increased or the weather temperature is high. When accidental limbs hit a wall or a grounded device, they may also cause electric shock when they encounter leakage. Insulation boots must prevent the rest of the body from being grounded during operation. In rainy weather, although insulated boots or insulated gloves are worn, necessary rain gear must be provided. Prevent the insulation protector from electric shock caused by moisture conduction.

What effect does the new national standard of the high-voltage insulated boots inner electrode replace the water by the metal ball on the test result?

The new national standard replaces water with a metal ball as the internal level of the test is in line with international standards. The original national standard test method is more stringent than the foreign standards. Water is used as the internal electrode for the insulating boots. The insulation resistance of the insulating boots is reduced due to the water invasion test. Compared with international standards, there is an unreasonable aspect. Therefore, in the test verification voltage, it is not allowed to use water as the internal electrode, and it is even more forbidden to use the voltage higher than the preventive test in the preventive test.

What are the main differences between insulating gloves for live working and rubber high and low voltage insulating gloves?

Insulating gloves for live working allow live work in different voltage ranges. High and low voltage insulated gloves are auxiliary safety devices that do not allow live operation. Live working insulating gloves are type tested and sample tested according to the International Electrotechnical Commission IEC 60903 and GB 17622-1998. The test sample should be pre-soaked for 16 hours under the standard draft. The voltage test is to be carried out for 3 minutes. The minimum withstand voltage test (gloves Portions that are not submerged must be kept dry. For example, type 02 and sampling test of IEC standard is first to pre-soak 16 hours after dipping the insulation gloves for live working according to the standard (the verification voltage test for glove cuffs from the horizontal voltage 65mm and the minimum withstand voltage 75mm). At a rate of 3000v per second, the time is increased to 20kv and the time is 3 minutes. If it does not break down, the leakage current value does not exceed 20mA, and the power is cut off immediately. The lowest withstand voltage, that is, rises to 30 kV at the same boosting rate, that is, the voltage is cut off immediately. Routine test (factory test requirements) is to test for 1 minute under different types of verification voltage (without soaking for 16 hours). However, in order to ensure safety, our company's factory test is 3 minutes, high and low voltage insulated gloves, no pre-immersion water regulations, and no test that is much higher than the minimum withstand voltage of the test voltage. Users can purchase insulation gloves for live work according to different types of conventional test. Compliance is checked and the leakage current is less than 16mA (size 410mm in length).

Insulating gloves for live working Why did you find cracks in the test?

For high-voltage tests on live working insulating gloves, an arc is generated between the two levels under high pressure because the height of the water injection is not standard or the parts of the gloves that are not submerged in water are not dry, and the electric discharge occurs in the air to generate the sound of the buzzer and the air Ionization produces ionization of oxygen in the air into ozone. When the concentration of ozone increases, it causes great oxidative damage to rubber and causes cracking and destruction of rubber. The high-pressure test is a destruction test for rubber, and the test is to be destroyed once. Therefore, it is stipulated that preventive testing should be conducted during use to ensure the safety of users.

China Labor Insurance Network