How to choose when buying a circuit breaker? What are the selection criteria for circuit breakers?

Circuit breakers, as the name implies, are a kind of security protection tool. On the one hand, when the voltage is too large, it can automatically control the opening and closing of the circuit and shut down. On the other hand, the product can avoid the trouble of manual operation and protect the safety of the user as much as possible. What I explained to you today is the information about the various aspects of the circuit breaker, including its selection criteria and the methods and suggestions for the specific selection process. Friends who are interested in knowing can refer to the three products mentioned below to determine the worthy purchase. Circuit breaker products.

First, the selection criteria of circuit breakers

Touch: touch the shell material

There are two types of housing materials for circuit breakers: thermoplastic and thermoset. It is a thermosetting shell with a smooth feel, and it is a thermoplastic type when the hand is not particularly smooth. The thermoplastic type has the following advantages over the thermoset type:

1. It is elastic and not easy to break.

2. Environmental protection. Because the thermosetting type uses additives, it is polluted.

Schneider Electric's circuit breakers use a thermoplastic housing. Each circuit breaker product housing is made of the most stringent RoHS certification in the EU. It has excellent electrical, mechanical, flame retardant properties and is environmentally friendly and non-polluting.

Two wrenches: wrench handle

The most vulnerable part of a circuit breaker is the handle. Whether the handle is strong and durable directly determines the service life of the circuit breaker.

Taking Schneider circuit breakers as an example, Schneider circuit breaker handles are not only durable but also very flexible and textured, ensuring good insulation and mechanical strength. The service life is up to 10,000 times, which is 2.5 times the national standard. When the switch is closed, the sound is crisp and loud, and the unique quick-close function design has the following advantages:

Make phase and neutral line time gap

When the switch is turned on and off, the mechanism automatically closes quickly, is not affected by the operating speed of the person, greatly limits the arc, reduces the electrical corrosion of the contact, and improves the service life.

Three defenses: anti-counterfeiting

As an important guarantee for the safety of electricity, the importance of circuit breakers should not be underestimated. How to avoid buying fake and shoddy products, we still use Schneider Electric's circuit breaker as an example to teach you how to identify.

Tu: Use a pen to smear on the surface of the label, wipe off the surface ink marks, and show the Schneider Electric anti-counterfeiting pattern.

Uncover: After uncovering the anti-counterfeiting film, it can be seen that the Schneider Electric trademark pattern is printed on the marking surface.

Photo: Use the violet light to illuminate the anti-counterfeit label, which shows the Schneider Electric logo pattern.

Second, the selection method of the circuit breaker

1. Circuit breaker rated current ≥ load working current: We can calculate the working current of the load by Ohm's law. It is necessary to pay attention to two-phase or three-phase, and then compare and select in the sample. The purpose of this is to meet the requirements of use. Otherwise it would be bad if you trip directly.

2, the rated voltage of the circuit breaker ≥ the rated voltage of the power supply and the load: Generally, the voltage we use is 380V or 220V. This should be easy for everyone. This can be understood in the same way as the current. It can't be small anyway, or else Can't get up.

3. Rated current of circuit breaker release ≥ load working current: The existence value of the trip unit is to protect the load. If the fault current increases, it can protect the load equipment from being burnt out. If it is small, it will frequently trip and lose its protection.

4, the circuit breaker limit switching capacity ≥ circuit maximum short-circuit current: this point is not much to say, anyway, it is to find two data according to this principle comparison, this point does not have a significant impact on the general use of small loads However, it is still necessary to consider extreme situations and choose the right one.

5, the end of the line is relatively short-circuit current / circuit breaker instantaneous (or short-circuit) trip unit setting current ≥ 1.25; this selection principle is also to achieve the purpose of protection, 1.25 is the empirical value, can also be calculated.

6. Circuit breaker undervoltage release rated voltage = line rated voltage: Undervoltage release is generally on the power supply side. When the power supply voltage is lower than the set value, the rated load is equal to the rated voltage of the line.

The above is an example of a circuit breaker, which is a switching device that can be used for cooperation. It can be further divided into a high-voltage circuit breaker or a low-voltage circuit breaker. On the one hand, the product can be widely used in various fields, including the power industry or other. In the daily life of the home, in another aspect, the circuit breaker has a mature design, so it can play a safety guarantee role, avoiding the current leakage caused by the excessive voltage, and can also reduce the trouble of manual operation and reduce the cost of manual operation. To help ensure a more satisfactory use.