Machine HealthWiring in a modern residential building without automatic switches, or as people call them “automata”, simply will not be accepted for use. Quite often in the electrical panel you can find the switches BA 47 29. They can be recognized by the gray case and the yellow key. This color does not depend on what power the “automatic” is designed for. A total of 19 current versions are presented in this line. The most powerful switch is able to “hold” 63 A, while the weakest is only half an ampere. Also, these machines are recognizable by their characteristic form.


  • 1 Superfluous detail in wiring
  • 2 Current rating
  • 3 Maximum switching capacity
  • 4 How is the circuit breaker
  • 5 Temperature conditions in the electrical panel
  • 6 Important features
    • 6.1 Electrical wear resistance
    • 6.2 Mechanical wear resistance
    • 6.3 Dimensions and weight

Superfluous detail in wiring

Circuit breakerSometimes emergency workers who come to eliminate malfunctions of the floor-mounted electrical panel for some reason assume that two or three automatic circuit breakers are a luxury, and that it is possible to throw a group of wires from the “injured machine gun” onto the whole, by pairing it with another by group. It is presented to the tenant so that his

the wiring was divided into two parts just for convenience, but the remaining automatic switch will completely “pull” the whole apartment on itself.

In order to assess how much an electrician is right, you need to know the main technical characteristics of the switch. Otherwise, you may face unpleasant surprises in the form of unauthorized disconnection of all wiring in the apartment only due to the fact that you plugged in an iron or electric kettle.

In general, having one “automatic” for the whole apartment is inconvenient. When there are two, usually one - the one that is more powerful - is responsible for the sockets located below, the second - for the chandeliers and their switches, as well as the outlet for the razor.

Sometimes at home regarding wiring plan differentlyand then one automatic switch-off part of the rooms, the second - the rest of the premises. But it is always possible to turn off one of these switches in order to repair part of the wiring, then how to use the other - through an extension cord - to make yourself a temporary lighting or connect a soldering iron, power supply, electric drill or any other necessary tool.

The zealous electrician does not leave you a choice: if the light can be adjusted with a flashlight, then the equipment or tools will have to be connected to the neighbors. In general, everything is being done so that the tenant does not eliminate the minor breakage in the wiring on his own. And even so that he could not replace the chandelier in the dark. And if it is the Arctic and winter is on the street?

In order for the “automatic” to be really replaced, you should always have it with you. Then the fitter will not get away from your request. The main thing is to choose the technical characteristics of this switch so competently that an emergency service worker felt your competence and imbued with respect for the client. To do this, we study our sample further, so that it is clear what to buy.

Current rating

Calculate how really your only switch can withstand the load dropped on it, you can, knowing what current it is rated for. The row for BA 47 29 switches will be:

  • Wiring item0.5 A;
  • 1 A; 1.6 A;
  • 2 A; 2.5 A;
  • 3 A;
  • 4 A;
  • 5 A;
  • 6 A;
  • 8 A;
  • 10 A;
  • 13 A;
  • 16 A;
  • 20 A;
  • 25 A;
  • 32 A;
  • 40 A;
  • 50 A;
  • 63 A.

Of these, in residential buildings it is rarely used in floor-by-floor panels “automata” at 32 A, as a rule, the values ​​of the rated current are taken lower. Knowing the current indicated on the case of the circuit breaker and the effective value of the voltage is 220 V, we can calculate the power as the product of these quantities. To get power in watts, you must multiply the voltage in volts by the current in amperes. If a rated current is 32 Aand the voltage is 220 V, then the power will be equal to 7040 watts.

When the electric stove, the iron, the washing machine in the water heating mode work at the same time, all chandeliers glow, while someone dries the hair with a hair dryer, then even then everything can be fine, but if at that moment it starts compressor the fridge, whose starting current is more significant, as the "automatic" can work.

In connection with the foregoing, the wiring in the apartments is divided into two or three groups: the circuit breaker should operate in the event of an accident or an overload that would cause the wires to overheat. By the way mains voltage up to 240 V can also be attributed to the specifications of the automatic switch. The frequency of 50 Hz is also its parameter.

Maximum switching capacity

Power machineThe switch may not work if you take too high a nominal. That is, the wiring may begin to overheat and melts if it is weak in itself, and the switch is set, say, to 25 or 63 A.

However, there is another situation in which the “automaton” is not destined to work - this very high currentin which the contacts of the breaker simply welded together, and the switch turns into a linear element of the electrical circuit. For BA 47 29 this value is 4.5 kA. This is another important feature, and such a monstrous overcurrent can not be allowed, otherwise the wiring can simply burn out, causing a fire in the building.

How is the circuit breaker

The design of BA 47 29 is such that it can operate in two emergency situations: short circuit and overload. To do this, there are two elements working on the opening of the circuit - a magnetic coil and a bimetallic plate.

With the principle of action of bimetallic plates, everyone is familiar with the school course of physics. There was considered a device thermostat in the iron. A different coefficient of expansion of metals in the plate leads to the fact that it bends when heated, moving away from the contact.

With an electromagnet, everything is a little more complicated. During a short circuit on the coil, the current increases sharply, which leads to the movement of its core. This is the same principle that is used in relays, magnetic starters, and so on. Only here the core is triggered to open, and almost instantly.

Response speed - another important technical characteristics of the "machine". It is for the bimetallic plate in practice is about 20 minutes from the start of overheating wiring. Naturally, when opening contacts, we are already talking about large currents. A spark in this situation can not arise, or an arc is formed. Therefore, the "automatic" is equipped with a special arc chamber.

Temperature conditions in the electrical panel

Circuit breakers BA 47-29.The circuit breaker "understands" that an accident has occurred or that the wiring is working in a non-staff mode, focusing on temperature characteristics. Therefore, it is completely logical that at low ambient temperature the tripping current at the switch may be different, namely - more passport nominal.

In the case of a considered BA 47, the denomination is verified not for normal conditions accepted in physics, but for 30 ° C. This temperature characteristic is called the reference temperature. It calibrates all circuit breakers of this type.

Consequently, the choice of the “automaton” may also depend on how well the place where the floor panel is located in your house is heated. If it is a vestibule for several apartments (“pocket”), then there will always be warmer than just on the staircase.

If you live on a high floor, then there will also be warmer in winter than on the first floor, where the entrance to the entrance is located. By the way, another characteristic - the working temperature range - is impressive with this “automaton”. It ranges from - 40 ° C to + 50 ° C. Well, this switch does not make enough for the Yakut frosts to work there at street temperatures!

Important features

When it is clear what current to choose a circuit breaker, it's time to find out what is the most optimal cost for the device.

  1. Do not buy too cheap "automatic", because it may be a fake. It threatens with the fact that it will be made of cheaper metals, of fusible plastic. It can work, just that. For example, only one inclusion of the refrigerator can provoke “knocking out” of a fake switch, which, besides, it can turn on quickly enough, and then, from too frequent alarms - soon and not at all burns out.
  2. If you buy a “machine” in an expensive store, then it will most likely be of high quality. The same applies to online stores: they must be solid sites, and not "one-day". So we proceeded smoothly to the technical specification - time between failures. In switches, it cannot be measured by time, so it is expressed in the number of operations.

Electrical wear resistance

This characteristic for the sample in question is 6000 on-off. At the same time, it does not matter whether the “automatic” was turned off forcibly, or it worked itself. Electrical wear resistance depends on the extent to which the electrical conductivity of the contacts is maintained. With each shutdown, they can oxidize under the action of an arc. Breaking in vacuum makes it possible to avoid oxidation.

Mechanical wear resistance

Switch automatic series BA47-29.With mechanics, everything is much simpler. Plastic parts and springs must not be damaged. For BA 47 29 this value is equal to 20,000 on-off. A fake switch can break down mechanically much faster. Therefore, you should trust only reputable stores, if you buy such a type of switch.

Why it is necessary to be afraid of a fake? Because the switches of this series produced in China, moreover, a very solid enterprise. However, in the same China, and in our territory they can forge such products using the cheapest materials. Then, in which case, there is always an excuse that the goods are Chinese, and therefore useless. But the real manufacturer is ready to submit a certificate of quality to his machine, and sellers should have this paper.

Dimensions and weight

It should also consider the technical parameters:

  • weight;
  • dimensions;
  • form factor.

An authentic circuit breaker of this type must have characteristic groove under landing on din-rail. The polarity of such a switch does not exceed four. Unipolar switches are used in homes.

Sometimes, for the amplification of the current put bipolar. The four-pole ones are used, naturally, for a three-phase network. The width of the single pole switch is 18 mm. Accordingly, the bipolar switch will be 36 mm wide, and so on. The mass of the single pole is 100 g. The height of the “automaton” is 80 mm.

And the last characteristic is type of performance on instant disengagement. These types are denoted by Latin letters. For our switch there are three letters - B, C, D. The first two types are suitable for use at home. The third type is more often used for three-phase engines. He has a place in factories, industrial kitchens, etc.