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What is RCD, application, how to connect
The system of electrical safety and power supply for suburban and country houses is a very urgent problem. The possibility of electrical wiring failure or unforeseen emergency situations with household electrical equipment and devices suggests the installation of a residual current device (RCD).
Content
- What is an RCD
- Principle of Operation and Design
- RCD single-phase and three-phase
- Differential automata video
- RCD connection diagram video
- Where is RCD or diffavomat used
What is an RCD
It is no secret that touching live parts of household appliances poses a real threat to human life in some cases. A special residual current device (RCD) is intended for reliable protection against the possibility of electric shock. Devices provide protection against the possibility of fire and fire.
The ideal option for protecting the premises of country and country houses from short circuits and wiring malfunctions, as well as household appliances and equipment, is the installation of an RCD.
Principle of Operation and Design
The principle of operation of the residual current device is based on the physical phenomenon of the appearance of an EMF in the control winding and a differential current transformer. The design of the residual current circuit breaker is a ferromagnetic core having three windings. Primary current windings (phase and zero) induce oppositely directed continuous magnetic fluxes in the cores. The primary winding is included in the phase wire, the secondary winding in the neutral wire, the third winding to the starting relay. With a favorable location, which means that there are no current leaks, the total magnitude and power of the magnetic flux are zero. In the event of asymmetry in the system, when a leakage current appears in the wiring, an electromotive force appears in the control winding. The appearance of a rapid electromotive force causes an instantaneous actuation of the relay, which in the controlled circuit opens phase and zero. Therefore, the operation of RCDs is distinguished by the components of the starting element: electromechanical and electronic devices.
RCD single-phase and three-phase
There are many connection schemes for the device. There are single-phase and three-phase UZO connection schemes.
RCD single-phase is used for load currents up to 63 A, and has the ability to turn off the load current and differential current.
Features of connecting a single-phase RCD:
limits switching and lightning impulse voltages of 2000 V level
allows connecting copper and aluminum conductors
does not lose sensitivity even when re-grounding the neutral conductor
has a bright light indication of the presence of voltage in the network
The most common single-phase device is considered to be an UZO-VAD2 with two poles, with a rated on and off capacity of 3000A. At the same time, the devices provide shutdown with a sinusoidal alternating current and a constant pulsating differential current.
A three-phase RCD operates identically to a single-phase RCD. The only difference is the passage of the core window with four conductors: three phase and one zero. The three-phase device housing has four clamps and terminals.
Differential automata
And, finally, diffavomats are a universal device that combines a circuit breaker and an RCD in a single housing. Differential automata serve as a kind of 2 in 1. Let us make a reservation right away, differential automata have nothing to do with the differentials from the course of higher mathematics. Similarly to a three-phase RCD, the diffavomat has four clamps.
How to teach to distinguish UZO from a diffavomat uninitiated in subtleties of electromechanics and people far from it? Incredibly simple: just watch the proposed video, in which in an accessible form they talk about markings and types.
Here it is necessary to note the 220 Pro electrics store, in it you will find ABB circuit breakers, ABB difavtomaty.
Video
RCD connection diagram
The owners of suburban and country houses are always interested in: How to connect an UZO or a diffavomat ?.
The most favorable place to connect the device in a country or country house is considered the maximum proximity to the entry point. Given the constant monitoring of the power grids of their power consumers, RCDs are installed after the power meter. With this type of connection, there is a complete de-energization of the section powered by the line.
The system of the protective shutdown device and its principle of operation is to constantly monitor the set value of the difference in the magnitude of the current. This is the difference in current between the phase and neutral wires. However, the consumer does not have to track anything. Reliable devices will take care of this. The leakage current is the cause of the difference to which the RCD responds. The device will constantly mechanically operate until the wiring malfunction or emergency is rectified. Therefore, the question arises: How to connect the device correctly? Undoubtedly, it is more reliable to provide the connection of protective devices to professionals from specialized companies. If you feel full confidence and a sufficient level of knowledge, then the installation and connection of protective devices can be carried out independently.
Before you make the installation of an UZO with your own hands in a country or country house, it is suggested that you watch the video.
Video
Where is RCD or diffavomat used
Issues regarding the use of devices are regulated activities. The need for the use and subsequent application of RCDs is specified in the official document of the EIC 7th edition. Requirements for the device RCD. GOST R 50807-95. Therefore, they are considered in the case of power supply to consumers from the 380/220 network and the standard TN-S grounding system.
Today, UZO and diffavomat are the only high-speed means of protection against electric shock.
Thanks to the versatility and perfection of the design, residual current circuit breakers and diffusers are successfully used almost everywhere. Moreover, the quality of the operation of diffavomats does not depend on the brand of the manufacturer’s brand and the cost of the device. Do you want to verify this yourself? Verified by experts!
