How to choose a RCD for installation in an apartment

For those who are worried about protecting theirhome from electric shock, the question arises: how to choose a RCD for an apartment or a house?
Because of the abundance of these devices by classification and type, you can get not what you need, and all efforts to protect the family will be in vain.
This article will help you in choosing this device.

The use of protection devices in the apartment

RCDs at the entrance to the house or apartment are necessary to protect against the negative impact of electric current on the human body, which directly touched the live parts of the electrical equipment or its body, which is under tension, due to the failure of its separate parts.

Also this device serves to protect against the ignition of electrical wiring during aging or damage to insulation of wires and cables.
It should be taken into account that the RCD is disconnected with a leak to the ground, but if you take the phase and the working zero, it will regard it as a load connection and the trip will not occur, which is fraught with tragedy.

The device of the automatic device of protection of the house

The device of the RCD includes: a toroidal core made of a certain type of ferrite, two primary coils( in single-phase RCD), made of a copper wire of not less than the current rated load, one secondary coil of thinner wire andmore turns.
The executive mechanism is designed to disconnect the power contacts in the event of a ground leakage, a test button with the resistance necessary to check the RCD for operation, when pressed, which changes the currents in the phase and zero coils, which triggers the tripping mechanism, the current amplifierin the RCD with electronic control), and the housing of the device.

Consider the principle of the RCD without grounding

By and large, the grounding conductor is not needed for operation, since the phase and the working zero are used. These two conductors pass through a kind of current transformer with a control winding.
Suppose the load is 10 amperes. On the phase conductor, a current of such a force will flow to the load. And passing through the load, it returns to zero conductor with the same parameters. As soon as a person touches the boiler body, for example, the tan burned out and the potential appeared on the body, some of the current begins to flow through the body into the ground and the difference in currents on the phase and zero conductors changes. These miserable changes lock the control coil and transmit to the relay, which in turn triggers the release mechanism and cuts the line from the power supply.

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What type of RCD is applicable in houses and apartments

When asked which type of RCD to put on the input to the apartment, the answer is simple - a machine with differential protection( type AC-for AC or type A-for pulsating and alternating currents), and an electromechanical release that does not require an additional power source. Buy the device you need a good quality, for example, the German company ABB.She deserves great popularity with her quality of electrical goods, and an acceptable price. This will give a guarantee of reliability and safety.
Such machines, in addition to the leakage to earth, provide protection against short circuits and overloads on the current consumption.
Calculation of the differential protection automaton.
The first thing to do is to calculate which maximum current can consume electrical equipment in the house or apartment. We calculate their total power in watts, which is indicated on the nameplates of the devices, then divide the power by the mains voltage, and we get the current in amperes.
For example: the total power of the devices is 4000 watts. Divide by 220 volts and get -18 amperes. Therefore, the machine must be at least 20 amperes.
With regard to the leakage current, it is suitable for an ordinary apartment at 30 milliamperes. These are most often found in electrical stores.
If there is a shower cubicle and for extremely wet rooms, it is advisable to make a separate power line and install a 10-milliampere differential for safety.
For large mansions, where all the wiring can be up to a kilometer or more in length, the RCD at the input to the house is put at a nominal value of 100 milliamperes and above, since at this line length there is a leak that could lead to a false trip of the RCD.Next, it is necessary to connect the RCD in the shield to each group separately with a nominal value of 30 milliamps of leakage current. This will ensure the protection of a certain area.

Rated current of input automatons working in conjunction with RCD

The current rating of the machines connected to the RCD in the switchboard, both in the introductory and in groups, must be lower than the automatic machines with differential protection. This is necessary so that the load in the network rests on the usual protection automatons, since they cost ten times cheaper than automatic devices with RCDs. Also, high currents can cause an improper operation of the RCD.
Errors during installation.
A frequent mistake when connecting an ouzo in an apartment is that in grounded outlets a neutral wire that does not pass through the RCD and is used as ground is connected to a zero terminal in the socket. This leads to the shutdown of the machine with differential protection when trying to plug something into this outlet. If this happens, swap the ground wire on the grounding clamp of the knock out socket.
Also it is necessary to connect the wires correctly at the input to the device. Phase-to the contact & lt; & lt; L & gt; & gt; , and zero-to & lt; & lt;N & gt; & gt; .This will ensure the correct operation of the device.

How to check the RCD for operation of the

As already mentioned, this is provided with the & lt; & lt; & lt; test & gt; & gt; button.
But its work does not guarantee full protection. In order to fully verify the performance of the device, it is necessary to simulate a leak to the ground once a month. It can be done very simply. Take a bipolar LED voltage indicator of the type & lt; & lt; contact & gt; & gt;, determine where the phase is in the socket, insert one indicator contact into the phase, and the other touch the grounded conductor, for example, the heating battery or the metal water pipes. Also if it is in the country or in a private house just stick the pin into the ground and touch the second end of its pointer.
In normal operation, the RCD should work, since the leakage current of the LEDs is usually greater than 30 milliamps. In extreme cases, you can use a cartridge with an incandescent lamp at 220 volts. Also connect one end of the cartridge to the phase, the other to the ground. The result should be the same. If the RCD does not work, it's time to change it.

Important! Errors connecting the ouzo video