Electric energy has become an indispensable phenomenon of our daily life. Unfortunately, with the widespread use of electrical energy, accidents that we do not want can happen. Approximately one in four fires today is unfortunately caused by electricity. If the necessary precautions are not taken, this possibility will be very high. Therefore, security prevention are taken in electrical systems. These security prevention are primarily aimed at ensuring the safety of the employee and equipment.
There are various preventions to minimize the problems that may arise from the electrical facilities, the earthing system and the residual-current device are at the beginning of these. Both applications are very important for electrical systems, their purpose is to help the system work properly, to supervise and ensure human and equipment safety in case of failure.
Electrical energy, which we are obliged to use at every moment of the day, which facilitates our lives, may create serious dangers for human health when necessary safety precautions are not taken. Leakage current in the electrical installation can lead to serious injury or even death to man. It can create burns in deep tissues at the points where electric current contacts and enters and exits the body.
Injuries to be caused by electric shock depend on 3 main factors. These;
Beside these 3 main factors, there are 5 factors. These;
According to EN60947-1 standard, the threshold value of the current that will be life-threatening to humans is 30mA. The person exposed to electric shock is affected in different ways depending on the amount of current passing over him. The effects that will occur as a result of an alternating current of 110V and 60Hz entering and exiting the body for 1 second are as follows.
It is obvious that electric current over 30mA can create serious problems for human health. Therefore, 30mA residual-current device should be used for the purpose of protecting human health.
Residual current device is a circuit element that ensures the safety of people and equipment put into the system for taking measures against any electrical leakage in the electrical system. This circuit element ensures that the system shuts down if there is a difference between the currents passing through the phase and the currents leaving the neutral. This element, located in the electrical circuit and put into operation against leakage current, prevents any accident that may occur when the leakage current value in the system turns on the system when it reaches a certain value.
Residual current device are two types, 30mA and 300mA, depending on the operating sensitivity. 30mA residual current device protects human life; The 300mA device is used against a possible fire in the facility.
The working principle of the leakage current relay is a magnetic circuit element that operates depending on the current difference between the phase current and neutral current. If the phase and neutral currents passing through the toroidal measurement transformer inside the leakage current relay are equal, no magnetic field is formed and the system continues to operate in this case. However, the differences between the phase and neutral cut the electrical energy by switching the system with the magnetic field it will create by passing through the toroidal current transformer. In this way, leakage current risk is prevented in installations with the risk of harming human health.
It also has a test button to see if the device is working. The purpose of this button is to check whether the device connected to the circuit will open the circuit in any leakage situation. The 30mA residual current device, which is used to protect human health, closes the system with the current difference between phase and neutral exceeding 30mA.
Electrical Internal Plants Regulation In the 18th article, 300mA residual current device should be used in the electrical installation entrance section for fire protection. In the secondary distribution lines, in order to ensure the safety of people, a thermal magnetic switch or automatic fuses must be installed together with a 30 mA residual current device. It is necessary to provide selectivity in all protection elements.
The points to be considered in the use of the leakage current protection relay are mentioned in the Grounding Regulation in Electrical Facilities.
In article 315 of the Occupational Health and Safety Regulation, it has been deemed appropriate to install a leakage current protection relay to prevent the electrical leakage from exceeding a certain level, in order to open the circuit in the case of grounding devices in grounded devices.
Residual current device that have to be used in homes and commercial building; As a result of incorrect connections in the installation, it constantly opens the system with the wrong use of the neutral line. Unfortunately, instead of examining and solving the problem, the owner of the building falls into an error such as canceling the residual current device. This situation is very dangerous for both life and property.
Problems should be identified and resolved in the problems of businesses related to residual current relays. It is aimed to prevent possible problems by transmitting the current through the ground. It should be known that bypassing leakage current relays will be the beginning of larger problems, not the solution of the problem. In this context, it is necessary for companies that have problems in leakage current to receive professional and permanent solutions to their problems by getting technical support from specialized companies.