6 important criteria for selecting a circuit breaker

Basic selection criteria for

So, let's look at how to choose the most important parameters of the device for protecting the wiring in the house and apartment.

1. Short-circuit current. In order to select a circuit breaker for short-circuit currents, it is necessary to take into account an important condition - the rules of the SAE automatons with the highest breaking capacity of less than 6 kA are prohibited. To date, devices can have ratings of 3;4.5;6 and 10 kA.If your house is located next to a transformer substation, you need to select a circuit breaker that operates at a short-circuit of 10 kA.In other cases it is quite enough to choose a switching device with a nominal value of 6000 Amer. Rated current( operating).The next, no less important criterion for choosing an automaton for a home is the nominal current. This characteristic displays the value of the current over which the circuit will disconnect and, accordingly, protect the wiring from overloads. To select the appropriate value( it can be 10, 16, 32, 40A, etc.), it is necessary to rely on the cross-section of the home wiring cable and the power of the electric power consumers. It is on how much current is able to pass the wires through itself and at the same time, what total power of all household appliances, the operating current of the switching device will depend. In this case, in order to select the appropriate characteristic of the circuit breaker, we recommend first determining the cross-section of the cable in your house or apartment, after which you are guided by the following tables:
   
   
2. Tripping current. Simultaneously with the working current of the machine it is necessary to select its rating according to the operating current. As you know, with the inclusion of powerful electrical appliances, the starting current can be much higher than the rated current( up to 12 times the value).In order for the circuit-breaker not to work, having perceived the activation of the motor as a short-circuit, it is necessary to select the correct class of the switching device. To date, for household use Classes B, C and D can be used. For a house and an apartment it is best to choose a Class B device if the kitchen is equipped with a gas stove and there are no powerful electricity consumers. If an electric stove is installed or a powerful electric boiler, it is better to choose a suitable Class C automatic machine. Well, if you have high-power electric motors in your private house, you must select a switching device labeled "D".
3. Selectivity. This term implies the disconnection in an emergency situation of only a certain, problematic area, rather than all the electricity in the house. There is already a need to dig a little into the logical chain and choose the values ​​of the circuit breakers according to the serving line. The top of the so-called branching should be occupied by an introductory machine, the value of which should not exceed the maximum permissible load on the wiring, starting from the wire section. The rated current of the input switching device must exceed the value of the operating current of all other downstream circuit breakers in the shield. For a private house, it is recommended to select a 40A apparatus for input, 32A for an electric stove, 25A for electric appliances, 25A for electrical outlets, 16A for sockets and 10A for lighting. When choosing such an option for assembly of the switchboard, the selectivity condition will be satisfied.
4. Number of poles. Another, not less important criterion of choice, with which, as a rule, there is the least amount of questions. So, for a single-phase 220 volt input, it is recommended to select a two-pole single-phase machine. For lighting and separately connected household appliances( for example, a washing machine, water heater, air conditioning) you need to select a suitable single-pole circuit breaker. If you have a three-phase power network in your house, buy a four-pole switching device. Well, to protect the engine from overcurrent, you need to choose a three-pole automatic device for 380 volts.
5. Factory manufacturer. It is very important to choose the correct firm of the machine, otherwise when buying a counterfeit, it's far from a fact that the above parameters are actually the same in fact. As a result, at the short-circuit current, the electromagnetic release may not work and, as a consequence, a fire in the house. In order to avoid this, it is recommended to select switching devices and other automation only from high-quality companies. We provided the rating of the best manufacturers of circuit breakers in the corresponding article!

We also recommend viewing the video instruction, which provides all the necessary tables and formulas for choosing a circuit breaker for current, power and cable cross-section:

The listed selection criteria for the circuit breaker are basic, and first of all pay attention to these parameters. It should be noted that saving on vending machines is very stupid! The difference between a quality product( from the manufacturer ABB or Schneider Electric) and forgery is not too great, given that your house is at stake and, more importantly, life!

Unacceptable errors when purchasing

There are several errors that can allow electricians-beginners when choosing a circuit breaker in terms of current and load. If you incorrectly select a protective automatics, even slightly "overshooting" with a nominal value, this can entail many adverse consequences: the operation of the machine when the appliance is switched on, the wiring will not withstand current loads, the service life of the switch will quickly decrease, etc.

• First of all, focus not on the power of household appliances, but on electrical wiring. It is not necessary to select the machine only on the characteristics of electrical appliances, if the wiring is old. The danger is that if, for example, to protect an electric stove, you choose a model at 32A, and the cross section of the old aluminum cable can withstand only 10A current, your wiring will not withstand and melt quickly, which will cause a short circuit in the network. If you need to choose a powerful switching device for protection, first of all replace the electrical wiring in the apartment with a new, more powerful one.
• If, for example, when calculating the appropriate rating of the machine for the working current, you have an average value between the two characteristics - 13.9A( not 10 and not 16A), give preference to a larger value only if you know that the wiring can withstandcurrent load of 16A.
• For a summer residence and a garage it is better to choose the automatic switch more efficiently, becauseHere, a welding machine, a powerful submersible pump, an induction motor, etc. can be used. It is better to anticipate the connection of powerful consumers in advance so that you do not overpay for buying a switching device of a higher denomination. As a rule, 40A is quite enough to protect the line in domestic conditions of use.
• It is desirable to pick up all the automation from one, high-quality manufacturer. In this case, the probability of any discrepancy is minimized.
• Buy goods only in specialized stores, or even better - from an authorized distributor. In this case, you are unlikely to choose a fake and besides, the cost of products from a direct supplier is usually a bit lower than that of intermediaries.

By the way, to understand the original you buy or cheap fake, you need to visually inspect the machine, as shown in the video:

That's the whole technique of choosing the right machine for your own house, apartment and villa! We hope that now you know how to choose a circuit breaker for current, load and the rest, no less important characteristics, and also what mistakes should not be allowed during the purchase!

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