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How to select the RCD to be installed in the apartment

those, who are concerned about protecting their home from electric shock, the question arises: how to select the RCD for an apartment or house?

Due to the abundance of these devices for the classification and type, you can buy not, what do you need, and all efforts to protect the family will be in vain.

This article will help you in the selection of this device.

The use of circuit breakers in the apartment

RCD at the house or flat necessary to protect against the adverse effects of electric current to the human body, which directly touched the live parts of electrical equipment or housing, under voltage, due to the failure of its individual parts.

Also, this device serves for protection from fire wiring in aging or damaged wire and cable insulation.

Should be considered, RCDs that turns off earth leakage, but if you take up the working phase and zero, they regard it as a load connection and disconnection does not happen, which is fraught with tragedy.

Protection device home machine

The apparatus includes a RCD:

  1. toroid, made of ferrite certain brand.
  2. The two primary coils (single-phase RCDs), made of copper wire cross-section of not less than the rated load current.
  3. A secondary coil of thinner wires and with a large number of turns.
  4. Actuating mechanism, intended to disconnect the power contacts in the event of an earth leakage.
  5. Test button resistance, I needed to check on the performance of the RCD, when you press, that does not change in the phase currents and zero coil, that triggers the disconnection mechanism, current amplifier (in RCDs with electronic control).
  6. housing unit.

The operating principle of an RCD without grounding


By and large,, grounding conductor for he does not need, since phase is used and the working zero. These two conductors pass through a kind of a current transformer with a control winding.

Suppose the load 10 ampere. By phase conductor to the load current will flow such force. And passing through the load, He returned on the neutral conductor with the same parameters. Once a person has touched the boiler body, eg, which went bankrupt and tan on the body appeared potential, the portion of the current through the body starts to leave the ground and the current difference in the phase and neutral conductor varies.

These minuscule changes captures and transmits the control coil of the relay, which in turn, actuates to a trip mechanism and disconnects the line from the power supply.

What type of RCD is applicable in homes and apartments


On the question of what type of RCD put on entering the apartment, the answer is simple - the machine with the differential protection (type AC - AC or type A - for pulsating and alternating currents), and an electromechanical release device, not requiring an additional power source. Fly the device must be of good quality, such as the German company ABB. She has earned a lot of popularity for their quality electrical, and acceptable price. This will ensure the reliability and safety.

Such machines besides tripping earth leakage, provide protection against short-circuit and over-current consumption. And your safety is paramount!

Calculation of the differential circuit breaker

The first thing you need to calculate what the maximum current can consume electrical equipment in the house or apartment. We believe their total wattage, which is indicated on the rating plate, then divide power at mains voltage, and obtainable current in amperes.

for example: total power devices- 4000 watt. I share the 220 volts and get 18 amperes. Consequently, Machine should not be less than 20 ampere.

Regarding the leakage current, it is suitable for ordinary apartments on 30 milliampere. These most often occur in the electrical shop.

If there is a shower and particularly in humid conditions, it is advisable to make a separate power line and install Emergency circuit breakers for more security on 10 milliampere.

For large mansions, where all the wiring length can total up to a kilometer or more, RCD at the house put a face value of 100 milliamps and up, since a length of the line is unavoidable leakage, which can lead to a false alarm RCD. Then you need to connect the RCD in the panel on each group separately rated 30 milliamperes of leakage current. This will provide protection from an area.

Input current denomination machines, working in tandem with the RCD

Current denomination machines, connected to the RCD as an introductory panel, and in groups, should be below automata with differential protection. It's necessary, the load on the network fell on the usual circuit breakers, since they are ten times cheaper machines with RCD.

Also higher currents can cause incorrect operation of the RCD mechanism.

An installation error

A common mistake when connecting ouzo in the apartment is, that a grounded outlet neutral wire, not passing through the RCD and is used as a grounding, Clem is connected to the zero in the socket. This disables the machine with differential protection when you try to turn anything into this socket.

  1. If this happens, reverse zero conductor to the grounding Clem embossing outlet.
  2. It should also be properly connected the wires at the inlet of the device. Phase - to contact «L», and a zero - in the «N». This will ensure correct operation of the device.

How do I check on the performance of the RCD

As mentioned, To do this, a button "test".

But her work does not guarantee complete protection. To fully make sure it is working properly, necessary once a month to simulate an earth leakage. This can be done very simply:

  1. Take a two-pole voltage LED pointer type "contact".
  2. Locate phase outlet.
  3. Insert one pointer in contact phase, while others will affect the earth conductor, eg, a radiator or a metal water pipe. Also, if in the country or in a private house just stick a pin into the ground and touch its second end pointer.

In normal operation,, RCD should trip, since the leakage current of the LED is typically longer 30 mA (milliampere). Also, one end of the cartridge to connect the phase, the other on the ground. The result should be the same. If the RCD does not work, it is time to change it.

In the extreme case, you can use a cartridge with a bulb on 220 volt.

Connection Errors video RCD


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