To everyone's safe use, must pay attention to the principle of selection leakage circuit breakers, here to share with you, I hope you can benefit:

1. To select the total leakage circuit protection

• Trunk or the entire network based on the normal leakage current of the circuit and equipment is that operating current should be greater than the leakage current of 2.5 times the normal operation of the grid.
• Leakage circuit breaker equipped with the stand-alone. Operating current should be greater than the leakage current in the normal operation 4 times.
• Branch lines for leakage circuit breaker, the operating current should be greater than the leakage current of 2.5 times the normal operation of the line, but also more than 4 times the maximum leakage current line electrical equipment leakage current.

2.  If the line is not easy to measure the leakage current or an electrical device, may be estimated by the following empirical formula:

Lighting circuit or residential electricity circuit: the earth leakage breaker operating current IDZ> ISJ / 2000; Power and Lighting mixing circuit: operating current leakage breaker IDZ> ISJ / 1000. equations IDZ operating current for the earth leakage circuit breaker, ISJ is the maximum current in the circuit.

• 380V three-phase three-wire electric power supply apparatus should be used in three-pole or four-pole four-wire four-wire leakage circuit breaker. 220V single-phase power supply the electrical equipment should be used two-pole two-wire wire or monopolar leakage circuit breakers.
• 380V three-phase three-wire electric power supply apparatus should be used in three-pole or four-pole four-wire four-wire leakage circuit breaker.

3. Choose according to the purpose of use and the place where the electrical equipment is located

• Direct contact with electric shock protection

Due to direct contact with an electric shock hazard depending on the location and purpose of use where electrical equipment is relatively large, causing serious consequences, so choose a higher sensitivity leakage circuit breakers, electric tools, mobile electrical equipment and temporary line, should be installed in a loop current of 30mA operation, the operation time of the earth leakage circuit breaker in the 0.1s. More residential household appliances, preferably mounted on the rear into the household power meter. If the shock is easy to cause secondary damage once (such as aerial work), should be installed in a loop current of 15mA operation, the operation time of the earth leakage circuit breaker in the US. For hospital medical electrical equipment should be installed operating current is 6mA, action time leakage circuit breakers within the US of the.

• Indirect contact electric shock protection

Different places indirect contact electric shock, can cause varying degrees of personal injury, so the different places of different leakage circuit breakers should be installed. It places greater dangers of electric shock easily, requiring a relatively high sensitivity of the earth leakage circuit breaker. inMoist places than in a dry place much greater risk of electric shock, the general operation of the installation shall 15-30mA current, operation time of the earth leakage circuit breaker in the 0.1s. Water for electrical equipment, the operation should be installed. Current 6- l0mA, the operation time in the US earth leakage circuit breaker. For the operator must stand on metal objects or metal containers in the electrical equipment, as long as the voltage is above 24V, the mounting operation should be at 15mA or less, the operation time of the earth leakage circuit breaker in the US. Electrical equipment fixed voltage of 220V or 380V, the resistor to ground when the housing 500fZ or less, may be installed stand-alone operation current of 30mA, the operation time of the earth leakage circuit breaker in the 0.19. Rated current of 100A or more large electrical device or power supply circuit with a plurality of electrical devices, installable operating current of 50--100mA leakage circuit breakers, electrical equipment grounding resistance at 1000 or less, can be installed operating current 200-500mA earth leakage circuit breaker.