A leakage circuit breaker is a switch that can automatically operate when the leakage current in the circuit exceeds a predetermined value. Commonly used earth leakage circuit breakers are divided into two types: voltage type and current type, and current type is divided into two types: electromagnetic type and electronic type. Leakage circuit breakers are used to prevent personal electric shock and should be selected according to the different requirements of direct contact and indirect contact electric shock protection. So, what is the working principle of a leakage circuit breaker? What are the models of leakage circuit breakers? What is the difference between a leakage circuit breaker and a leakage protector? If you have this need, you may wish to follow me to learn about the leakage circuit breaker model and other related knowledge about the leakage circuit breaker.
Leakage circuit breaker model
5SM11110 residual current protection circuit breaker (125V~230V) 16A2P10mAAC type 55mm
5SM11116 residual current protection circuit breaker (125V~230V) 16A2P10mAA type 55mm
5SM13116 residual current protection circuit breaker (125V~230V) 16A2P30mAA type 55mm
5SM13120 residual current protection circuit breaker (125V~230V) 25A2P30mAAC type 55mm
< p> 5SM13126 Residual current protection circuit breaker (125V~230V) 25A2P30mAA type 55mm5SM13140 Residual current protection circuit breaker (125V~230V) 40A2P30mAAC type 55mm
5SM13146 Residual current protection circuit breaker (125V~230V) 40A2P30mAA type 55mm
5SM13160 residual current protection circuit breaker (125V~230V) 63A2P30mAAC type 55mm
5SM13166 residual current protection circuit breaker (125V~230V) 63A2P30mAA type 55mm
5SM13170 Residual current protection circuit breaker (125V~230V) 80A2P30mAAC type 55mm
5SM13176 Residual current protection circuit breaker (125V~230V) 80A2P30mAA type 55mm
5SM13420 Residual current protection circuit breaker (230V~400V) 25A4P30mAAC type 55mm
5SM13426 Residual current protection circuit breaker (230V~400V) 25A4P30mAA type 55mm
5SM13440 Residual current protection circuit breaker (230V~ 400V) 40A4P30mAAC type 55mm
5SM13446 residual current protection circuit breaker (230V~400V) 40A4P30mAA type 55mm
5SM13460 residual current protection circuit breaker (230V~400V) 63A4P30mAAC type 55mm
5SM13466 Residual current protection circuit breaker (230V~400V) 63A4P30mAA type 55mm
5SM13470 Residual current protection circuit breaker (230V~400V) 80A4P30mAAC type 55mm
5SM13476 Residual current protection Circuit breaker (230V~400V) 80A4P30mAA type 55mm
5SM13526 residual current protection circuit breaker (500V) 25A4P30mAA type 55mm
5SM13546 residual current protection circuit breaker (500V) 40A4P30mAA type 55mm
p>5SM13566 Residual current protection circuit breaker (500V) 63A4P30mAA type 55mm
5SM14120 Residual current protection circuit breaker (125V~230V) 25A2P100mAAC type 55mm
5SM14126 Residual current protection circuit breaker 5SM14140 residual current protection circuit breaker (125V~230V) 25A2P100mAA type 55mm
5SM14140 residual current protection circuit breaker (125V~230V) 40A2P100mAAC type 55mm
5SM14146 residual current protection circuit breaker (125V~230V) 40A2P100mAA type 55mm
5SM14160 residual current protection circuit breaker (125V~230V) 63A2P100mAAC type 55mm
5SM14166 residual current protection circuit breaker (125V~230V) 63A2P10
0mAA type 55mm
5SM14170 residual current protection circuit breaker (125V~230V) 80A2P100mAAC type 55mm
Working principle of leakage circuit breaker
Composition and operation of leakage circuit breaker Principle The leakage circuit breaker has two functions, one is the function of a circuit breaker, and the other is the function of leakage protection. The function of the circuit breaker is the same as that of a general low-voltage circuit breaker, serving as a switching device that operates infrequently. The leakage protection part detects the residual current through the zero-sequence transformer, that is, by detecting the instantaneous current values ??of the phase line and neutral line in the protected circuit to determine the change in the leakage current to the ground.
When the circuit leakage current exceeds the specified value or someone gets an electric shock, it can automatically cut off the power supply within a safe time to protect electrical appliances, ensure personal safety and prevent equipment from causing fires due to leakage current, etc. Accident. The leakage circuit breaker is composed of operating mechanism, electromagnetic release, contact system, arc extinguishing chamber, zero sequence current transformer, leakage release and test device. All components are placed in an insulating shell. The leakage protection function of the digital small circuit breaker is provided in the form of a leakage accessory structure, which can be combined with the circuit breaker when necessary.
There are two types of leakage releases: electromagnetic type (ELM) and electronic type (ELE). The difference between them is that the leakage current of the former can directly operate the main switch through the release, while the leakage current of the latter The current must be amplified by the electronic amplifier circuit before the tripper can operate to operate the main switch.
Principles for selecting leakage circuit breakers
Choose according to the purpose of use and the location where the electrical equipment is located
1) Protection against direct contact with electric shock
Since direct contact is more harmful and the consequences of electric shock are serious, a leakage circuit breaker with higher sensitivity should be selected. For power tools, mobile electrical equipment and temporary lines, the operating current should be 30mA and the operating time should be installed in the circuit. Leakage circuit breaker within 0.1s. For residential buildings with many household appliances, it is best to install them behind the electric energy meter entering the home.
If an electric shock is likely to cause secondary injury (such as working at heights), a leakage circuit breaker with an operating current of 15mA and an operating time within US should be installed in the circuit. For electrical medical equipment in hospitals, leakage circuit breakers with an operating current of 6mA and an operating time within US should be installed.
2) Indirect contact electric shock protection
Indirect contact electric shock in different places can cause different degrees of harm to the human body. Therefore, different leakage circuit breakers should be installed in different places. For places with high hazards that are prone to electric shock, it is required to use leakage circuit breakers with relatively high sensitivity. The risk of electric shock is much greater in humid places than in dry places. Generally, a leakage circuit breaker with an operating current of 15-30mA and an operating time of within 0.1s should be installed. For electrical equipment in the water, it should be installed in action. A leakage circuit breaker with a current of 6-10mA and an operating time within US. For electrical equipment where operators must stand on metal objects or inside metal containers, as long as the voltage is higher than 24V, a leakage circuit breaker with an operating current of less than 15mA and an operating time within US should be installed. For fixed electrical equipment with a voltage of 220V or 380V, when the shell ground resistance is below 500fZ, a single machine can be installed with an earth leakage circuit breaker with an operating current of 30mA and an operating time within 0.19. For large electrical equipment with a rated current of more than 100A or a power supply circuit with multiple electrical equipment, a leakage circuit breaker with an operating current of 50--100mA can be installed. When the grounding resistance of the electrical equipment is below 1000, a leakage circuit breaker can be installed. A leakage circuit breaker with an operating current of 200-500mA.
Select according to the normal leakage current of the circuit and equipment
1) Leakage circuit breaker for stand-alone machine. The operating current should be greater than 4 times the leakage current during normal operation of the equipment.
2) For leakage circuit breakers used in branch lines, the operating current should be greater than 2.5 times the leakage current of the line during normal operation, and should also be greater than 4 times the leakage current of the electrical equipment with the largest leakage current in the line. .
3) The operating current of the leakage circuit breaker for main line or total network protection should be greater than 2.5 times the leakage current during normal operation of the power grid.
If it is not easy to measure the leakage current of lines or electrical equipment, it can be estimated according to the following empirical formula:
Lighting circuit or residential power circuit: operating current of leakage circuit breaker IDZ>ISJ/2000;
Power and lighting hybrid circuit: the operating current of the leakage circuit breaker IDZ>ISJ/1000.
In the formula, IDZ is the operating current of the leakage circuit breaker, and ISJ is The maximum current in the circuit.
1) Electrical equipment powered by single-phase 220V power supply should use a two-pole two-wire or single-pole two-wire leakage circuit breaker.
2) For electrical equipment powered by a three-phase three-wire 380V power supply, a three-pole four-wire or four-pole four-wire leakage circuit breaker should be used.
The difference between leakage circuit breaker and leakage protector
Circuit breaker: A circuit breaker is a switching switch that controls an electrical circuit. If air is used as the arc extinguishing medium, it is called an air circuit breaker ( switch), if sf6 gas is used as the arc extinguishing medium, it is called a sulfur hexafluoride circuit breaker (switch). Circuit breakers are generally selected based on rated current (load) and used as the main switch of the electrical circuit.
Leakage protector and leakage protection switch:
Leakage protector and leakage protection switch: When an air switch has a leakage protection function, it is called a leakage protection switch. If it is an electrical device used solely for leakage protection, it is called a leakage protector. Leakage protector, because it does not have a manual shut-off and closing mechanism.
The principle basis for determining whether there is leakage is: the leakage protector detects the "inflow" and "outflow" of the power supply, because the current on the live wire is equivalent to the outflow point of the power supply, and The current in the neutral line is equivalent to the current "inflow" point of the power supply. When there is no leakage in the line, the current flowing into and out of the power supply is equal in magnitude and opposite in direction. However, when there is leakage in the circuit, the current flowing back to the power supply on the neutral line It should be less than the current value flowing into the electrical circuit from the power supply. When it reaches 30mA, the protector will operate and cut off the zero and live wires at the same time.
The current flowing into and out of the switch must be equal, otherwise it will be judged as leakage. When the leakage current reaches or exceeds a certain level, a protective action - tripping occurs. The judgment threshold can be set because the circuit is designed by us. It’s just that when applying, protectors with different sensitivities should be selected according to different occasions. The residual current refers to the vector sum of the instantaneous values ??of the current passing through the main circuit of the residual current action protection device (zero sequence transformer), expressed in its effective value. For a single-phase line, the residual current is the ground leakage current of the phase; for For a three-phase line, the residual current is the vector sum of the instantaneous values ??of each phase current, expressed by its effective value.
A leakage circuit breaker is essentially a plastic case circuit breaker equipped with leakage detection components. It mainly consists of a plastic shell, operating mechanism, contact system, arc extinguishing chamber, tripper, and zero sequence current transformer. and test equipment.
Editor’s summary: Current leakage circuit breakers are mainly used in low-voltage distribution systems where the neutral point of the transformer is grounded. Its characteristic is that when a person gets an electric shock, a leakage current is detected by the zero-sequence current transformer, causing the relay to operate and the power switch to disconnect. For more relevant information, please continue to pay attention to our website, more exciting content will be presented in the future.