Build Daily

August 12, 2017 18:07

Technical characteristics of circuit breakers

To date, when installing wiring can not do without this device.In any switchboard sure to set the opening gun and some additional lighting, outlets, and other groups of wires.Next we will look at why there is a machine, how it works and what specifications does.

  • Appointment
  • design
  • Specifications
  • General classification


First of all, let's deal with the fact that a circuit breaker (AB).

AB is a device that turns off the electricity at a certain site wiring for the following reasons:

  • a short circuit;
  • network congestion;
  • surges.

addition, this device can be used for what would "remove" the voltage in a particular area by wiring the operational shutdown (event held very rarely).

In simple terms, the AB is required for the protection of electrical appliances in case of failure wiring.

To your attention the video tutorial, which contains a full explanation of what the circuit breaker, and what his action principle:

Review of existing products
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there are many different Todayproducts for AC-Link.Each of the units has its own specific design, so in this article we will look at an example of a modular machine.

Thus, the device of the circuit breaker is made up of four main parts:

  • contact system (movable and immovable).The movable contact is connected to a handle and mounted in the stationary housing.power outage occurs by pushing the movable contact spring, and then opens the network.
  • heat (electromagnetic) release.Element, by means of which the contacts are opened.Heat release - a bimetallic strip that bends, opens the contacts.Bending occurs due to the heating current (if it exceeds the rated value).Such disengagement occurs at high loads on the power line.The action of the magnetic release is instantaneous, due to a short circuit.Overcurrent provokes movement of the solenoid core which actuates the release mechanism contacts.
  • arc suppression system.This part of the AB is represented by two metal plates which arc neutralized.The latter occurs when the circuit is carried out.
  • control mechanism.special mechanical lever used for manual disconnection or button (in other types of AB).

also provide to you a more detailed structure of circuit breaker:

Product Construction elements

In this video example clearly provided design and function AB:

detailed operating principle
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breaker has its own individual characteristics by which we carry out selection of a suitable model.

Symbols on the housing

main technical characteristics of the circuit breaker are:

  • Rated voltage (Un).This value is set by the manufacturer and is indicated on the front panel.
  • Rated current (In).Just set the plant and represents the maximum value of the current at which the protection will not work.
  • release (Ipn) Rated operating current.By increasing the current network to a value of 1.05 * 1.2 * Irn or Irn while operation will not occur.This value must always be lower than the rated current.
  • response time during short circuit (short circuit).In the event of short-circuit automatic turn off after a certain time of passage of the current through the device (response time).Also set by the manufacturer.
  • Maximum switching capacity of the circuit breaker.The value of extending short-circuit in which the device can still function normally.
  • setting the current operation.If this value is exceeded the unit instantly triggered and disconnects the circuit.Here products are divided into 3 types: B, C, D. The first type is used for mounting a long transmission line, triggering a range of 3-5 nominal operating current release (Irn).Device type C has a range of values ​​of 5.10 and is used in the lighting circuits.Type D is used to protect transformers and electric motors.Its operating range is from 10 to 20 Irn.

General classification

I would also like to provide you with the most generalized classification of circuit breakers for the home.Today, products are divided by the following features:

  • Number of poles: one, two, three or four.Single-pole and double-pole circuit breakers are common to use in a single-phase wiring.The latter two options are used for three-phase mains.
  • drive type.The machine can be operated manually (manual transmission) or at a certain distance (electric drive).
  • presence / absence of a current limiter.In the first case, the circuit is faster at fault becausecurrent limiter protects the wiring from the limit values ​​of the short-circuit current.
  • type release.Purpose and types of structure breakers data elements we considered above.Once again, the electromagnetic release is used for protection against short circuit and thermal - overload current.
  • Selectivity / non-selectivity of the product.This function allows you to adjust the response time AB.
  • fastening method.Usually fixing submitted retractable or fixed retainer.In the first case, the AV is installed on all known electricians DIN-rail (as shown in the photo), in the second case, the installation is carried out in the frame of the electric shields.

Using a DIN-rail

products can also be classified according to the degree of protection of the IP, amperage, current limiting and short-circuit method of connecting wires (or rather, conductors).

That's all you need to know about the device, the operating principle and the appointment of circuit breakers.We hope that the information has become for you a useful and new.
Also read:

  • How to select the RCD Housing
  • Which is better: Emergency circuit breakers or RCD
  • Why triggered RCD