1. In terms of structure LED light tubes are prone to problems in the three places where the lamp cap, the screw, the basic insulation and the contact of the accessible metal parts are contacted. The lamp holder needs to meet the torque test specified in GR18774-2002 and the size requirements specified in GR2799-2001. Among them, the torque test specified in GR18774-2002 requires that both before and after the high temperature test meet the requirements of clause 2.3.1 of the standard, that is, when the torque test is applied, the rotation between the parts of the lamp cap should not exceed 6°. The high temperature condition applied by the lamp cap is (125±5)℃, and the heating time is (2000±50)h. If G13 lamp holder is used, and the lamp power is greater than 40W, the high temperature condition is: (140±5)℃. High-temperature conditions and duration are more stringent for the assessment of LED tubes with plastic materials for the lamp caps. Using plastic lamp caps with low heat resistance, after applying such long-term high-temperature conditions, the plastic parts are likely to have softened.　　 The internal wiring of the LED light tube is mainly used to connect the lamp holder pin and the input and output of the built-in power supply. The built-in power supply is isolated from the aluminum casing by a sleeve. According to GR7000.1, the insulation between internal live parts and accessible metal parts must meet double insulation or reinforced insulation. This requires the insulation of the bushing to meet the electrical strength requirements of the reinforced insulation level.　　Second, internal wiring　　According to the requirements of the GR7000.1 standard, the internal wiring used by the LED tube needs to be evaluated in four aspects: wire diameter and insulation thickness, mechanical damage, insulation layer heating temperature, and whether the insulation meets the requirements. Generally speaking, there will be no problems with the internal line in the protection of mechanical damage, and the main problems will lie in the other three aspects. According to the requirements of the GR7000.1 standard, when the normal current is less than 2A (generally the working current of the LED light tube does not exceed 2A), the nominal cross-sectional area of the internal wire is not less than 0.4mm?, and the thickness of the insulating layer is not less than 0.5mm. In addition, from the perspective of insulation, since the aluminum shell is an accessible metal part, the internal basic insulation cannot directly contact the aluminum shell. This requires the internal wire to be a double insulated wire, unless there is a relevant certificate that can prove that the insulation of the wire can meet the reinforcement Insulation requirements, at this time, it is also possible to use single-layer insulated wires for internal wires. However, the internal wires used in LED tubes on the market rarely take into account the requirements of cross-sectional area, insulation thickness and insulation wire level at the same time. 3. Protection against electric shock. In terms of protection against electric shock, the EST laboratory reminds you that there may be two unqualified situations. The first is that there is no reliable connection between the lamp holder and the lamp body, which causes the lamp holder to be directly removed by hand. As a result, the test can directly contact the internal live parts; second, the internal insulation is not done well, resulting in leakage of the shell. 4. Insulation resistance and electrical strength. From the perspective of electrical classification, LED light tubes belong to the class II anti-shock type, which requires the input of the LED light tube to the touchable parts and the input to the installation surface to meet the reinforced insulation level. Insulation resistance and dielectric strength requirements. At present, many LED light tubes can pass the insulation resistance test, but the dielectric strength test fails, mainly due to the selection of the transformer with the built-in power supply and the installation position of the aluminum substrate of the LED module. Many companies choose to use non-isolated transformers for the purpose of saving costs or high power supply efficiency, which will cause the built-in power supply's input and output terminals to fail to meet the electrical strength requirements of the reinforced insulation level.