The reporter learned from the State Administration of market supervision that in accordance with the law of the people's Republic of China on product quality, the law of the people's Republic of China on the protection of consumers' rights and interests and the Interim Measures for the administration of product quality supervision and random inspection, the State Administration of market supervision comprehensively analyzed and judged the product quality and safety situation, and fully listened to the opinions and suggestions of all sectors of society, The national supervision and random inspection plan for 2020 annual quality was formulated and issued on May 8.

In its announcement, the State Administration of market supervision said that in 2020, the national supervision and spot check of product quality will adhere to the people's livelihood orientation and problem orientation, unify production and circulation, online and offline supervision, highlight the spot check of products concerned by the people and the decline of quality and safety level, and focus on the indicators related to human health, personal and property safety.

The spot check plan includes 131 products. Among them, there are 15 kinds of daily use and textiles, 30 kinds of electronic and electrical products, 16 kinds of light industrial products, 19 kinds of construction and decoration materials, 2 kinds of agricultural means of production, 20 kinds of machinery and security products, 7 kinds of electrical and material products and 22 kinds of food related products.

Among the 30 kinds of electronic appliances planned for supervision and random inspection, there are refrigerators, room air conditioners, household electric washing machines, water storage electric water heaters There are 22 kinds of household appliances such as heat pump water heater (heater); there are 5 kinds of electronic products (), including power adapter, active speaker, color TV, LCD and mobile power supply; there are also 3 kinds of lighting sources and lamps, including fixed general lamps, LED control devices and self ballasting LED lamps.

Among the 16 light industrial products planned for supervision and random inspection, there are three kinds of domestic gas appliances, including domestic gas fast water heater, domestic gas stove and gas heating water heater.

Among the two agricultural means of production planned for supervision and random inspection, in addition to compound fertilizer, there are pump products as agricultural machinery.

Among the 20 kinds of machinery and security products planned to be supervised and spot checked, there are 9 kinds of vehicle related products: Vehicle urea aqueous solution, motor vehicle brake fluid, motor vehicle external lighting and light signal device, motorcycle occupant helmet, automobile safety belt, automobile tire, automobile interior decoration materials, automobile brake lining and brake hose; There are three kinds of explosion-proof electrical products: explosion-proof electrical appliances, explosion-proof motors and explosion-proof lamps; There are two kinds of labor protection products: electrically insulated shoes and toe protection safety (protection) shoes; there are six kinds of safety technology prevention products: electronic door locks, locks, RMB discriminators, hazardous chemical packages (steel barrels), hazardous chemical packages (metal barrels and cans) and hazardous chemical packages (aerosol packaging).

Among the 7 kinds of electrical and material products planned for supervision and random inspection, there are 4 kinds of low-voltage appliances and electrical accessories, including residual current operated circuit breakers for household and similar purposes, overcurrent protection circuit breakers for household and similar places, distribution boards, extension cord sockets (with power adapters), as well as steel wire ropes, rubber sealing products, wires and cables.

Leakage circuit breaker is a switch that can act automatically when the leakage current in the circuit exceeds a predetermined value. The commonly used leakage circuit breakers are divided into voltage type and current type, and the current type is divided into electromagnetic type and electronic type. Voltage type leakage circuit breaker is used for low-voltage power grid with ungrounded neutral point of transformer. The utility model is characterized in that when a person is electrocuted, a relatively high voltage appears between the zero line and the ground, causing the relay to act and the power switch to trip. Current mode leakage circuit breaker is mainly used in low-voltage distribution system with transformer neutral grounding. The utility model is characterized in that when a person gets an electric shock, a leakage current is detected by the zero sequence current transformer to make the relay act and disconnect the power switch.

The following industrial electrical network editor will introduce the two faults encountered in the use of leakage circuit breaker and their solutions. The details are as follows:

Fault 1: the leakage circuit breaker tripped as soon as it was put into operation

（1） If the three-phase power line, including the zero line, does not pass through the zero sequence current transformer in the same direction, correct the wiring.

（2） . the circuit with leakage circuit breaker installed and the circuit without leakage circuit breaker are electrically connected, and the two circuits can be separated.

（3） . there is a fire and ground load in the line, and such load can be eliminated.

（4） . if the working zero line passing through the zero sequence current transformer has repeated grounding, the repeated grounding shall be eliminated.

（5） . if the leakage circuit breaker is faulty, it shall be replaced.

Fault 2: leakage circuit breaker misoperates

（1） Caused by overvoltage. If the circuit breaker can act when operating overvoltage occurs in the line, the delay or impulse voltage non action leakage circuit breaker can be selected, the resistance capacitance absorption circuit can be installed between the contacts to suppress overvoltage, or the overvoltage absorption device can be put into the line.

（2） Electromagnetic interference. If there is magnetic equipment or high-power electrical equipment nearby, the installation position of leakage circuit breaker shall be adjusted to keep away from such electrical components.

（3） Circulation influence. If two transformers operate in parallel, they have their own grounding. Because the impedance of the two transformers cannot be completely equal, circulation will be generated in the grounding wire, causing the action of the circuit breaker. In addition, the same transformer supplies power to the same load through two parallel circuits, and the current in the two circuits cannot be completely connected At the same time, circulation may also occur, so the two circuits should be operated separately.

（4） The insulation resistance of the working zero line is reduced. When the insulation resistance of the working zero line is reduced, if the three-phase load is unbalanced, a relatively large working current will appear on the zero line and flow to other branches through human ground, so that leakage current can appear on each leakage circuit breaker, causing the circuit breaker to misoperate.

（5） Improper grounding. If the zero line is grounded repeatedly, it will cause the misoperation of the leakage circuit breaker.

（6） , overload or short circuit. If the leakage circuit breaker has short circuit protection and overcurrent protection at the same time, misoperation will occur when the setting current of the overcurrent protection release is inappropriate. At this time, adjust the setting current value.f market supervision will publicly release the results of national supervision and random inspection of product quality to the public, and deal with violations of product quality according to law. While carrying out the national supervision and random inspection as planned, the State Administration of market supervision will also adjust the contents of the plan as appropriate according to the actual situation of the work, and organize special supervision and random inspection of unplanned products.