It is a leakage current relay that identifies leakage currents in an electrical installation and protects people's life and property safety. In fact, if there is a fuse system in the electrical installation, it would confuse people who do not have enough knowledge about why a leakage current relay is needed. Once a leakage current relay is detected in an electrical installation, it detects the leakage current that damages both the people and the electrical installation itself, the circuit elements and the electrical and electronic devices connected to the circuit in a very short time and cuts the passage of the electrical current by opening the circuit. In this way, possible dangers are avoided. The leakage current relay is based on phase and neutral balance in the installation. Under normal conditions, this balance should be equal. However, if there is a difference between the current flowing from the phase and the current leaving the neutral, if the currents are not equal to each other, there is an electrical leakage or short circuit somewhere in the system. In this case, the leakage current relay is activated.

Due to the high resistance of the ground line or the connection of the cable connected to the ground with another place, the leakage current cannot be removed from the electrical installation. In such cases, the leakage current becomes a very dangerous situation for human life and begins to pose a threat. If the leakage occurs over the 30 mA, it is not even internal to avoid irreversible problems. Almost every device and each machine creates leakage current in itself. In order to prevent these hazards that may occur here, an earth fault / residual current protection must be created in addition to the overcurrent protection so that automatic separation can take place. This system must be provided to minimize damage and damage to ground fault currents under the overcurrent protection detection level in products and equipment. When setting up these devices, they must be kept as low as possible and compatible with the correct operation of the equipment.

RCD devices separate the defective part or device from the supply source when the residual current reaches the specified opening threshold of the device when the insulation current occurs in a part of the system or in the devices, which is determined by the manufacturer and varies between the trip current threshold value 30 mA and 500 mA. The disconnection process is usually carried out at a value between 20 ms and 50 ms, ie between 50 and 1 periods in the 2,5 Hz system. of great importance. RCD residual current protection relay devices are the most important measures taken in terms of human safety for such systems. However, it is also important to protect the electrical devices against short circuit fault currents in the electrical installation.

Although the electrical fuse has a similar function, the current values ​​to be maintained by a fuse are higher than the leakage current relay. Like other conductors, current can pass through the human body. It can resist up to 50 volts in dry conditions and up to 25 volts in humid environments. Even the milliampere current flowing through the human body can have dangerous consequences on health. In general, the human body can withstand up to 30 mA. However, fuses are usually 10, 16 or 32 amps and do not blow before. This value is extremely risky for human life. A residual current relay is only activated if the difference between 30 mA is on and off. It provides more reliable protection in this respect. In addition, the residual current relay switches on immediately if there is a possible leakage current in the installation and creates a fire hazard and prevents the risk of fire. In practice, the 300 mA residual current relay is used for protection against fire.

Our company conducts measurements of leakage current relays in accordance with the relevant regulations, standards and test methods published by domestic and foreign organizations within the framework of electrical safety inspections. The standards considered in these studies are as follows: In case of a current difference between the conductors called phase and neutral in the power lines, the switch aiming to protect the line by opening the circuit is called the leakage current protection relay. In an active electrical circuit, the current entering through the phase line exits through the neutral line. If there is no leakage in the circuit under normal conditions, the incoming and outgoing current is equal to each other. However, in case of any leakage in the circuit, not all of the current flowing through the phase line will come out of the neutral part, but some of it will exit from the part where the leakage exists and in this case phase - neutral equation will be disturbed. The leakage current protection relay used on the power lines detects this inequality and opens the circuit and the negative effects that may occur due to leakage current are prevented.