Features of use and connection diagram of a two-pole machine

A special switching device is used to conduct currents under normal conditions and automatically turn off the voltage in cases of overload or short circuit. A two-pole circuit breaker is an electrical device with an automatic phase and zero, that is, two poles. At the moment of disconnection, the disconnection of the neutral and the phase occurs simultaneously. The equipment will be used for a single-phase network.

Features of the operation of single-pole and double-pole AB

The difference between a single-pole device and a two-pole circuit breaker is the number of networks monitored. Single-pole models are designed to turn off current on one line. Two-terminal networks are responsible for the two lines, comparing the indicators of the electron flow and establishing the correspondence values ​​for the normal functioning of the network.

The devices will also differ in the design of the release. On two-pole, a tripping element is installed, which immediately turns off zero and phase in both automatic and manual modes. Another difference is the ability to be used in conjunction with complex equipment. A single-pole can be connected to a single-circuit power supply, a two-pole - if you have household appliances that are unacceptable to be thrown on the same line.

The PUE rules prohibit the operation of single-pole models at the input.

Device and principle of operation

The two-pole circuit breaker is made in the form of a plastic case, equipped with contacts on the outside and a handle for opening / closing. The handle is connected to the platoon, which ensures the movement of the power contacts. They are closed by turning the knob to "On". The sealed case does not allow dust and moisture to seep inside.

Working units are located inside. These are two splitters - electromagnetic and thermal, which are responsible for stopping the device in the event of a network failure. The elimination of fires is provided by the arc chute. Combustion gases are removed from the inside through a special channel. To connect, you need to put protected wires into the terminals and tighten them with a screw.

Principle of operation

The two-pole differential automatic machine operates on the principle of electromagnetic induction. The measuring transformer-sensor reacts to the differences in currents that the input and output cables have. Thus, the device monitors the flow of the differential current, turning off the electrical circuit in case of abnormal values.

The transformer windings are designed according to the type of opposite connection, and each generates its own magnetic flux in the core. If the flux is equal, the secondary winding current will be zero. The presence of a magnetic flux in the core activates the appearance of the secondary winding current, which contributes to the activation of the protection mechanism.

When the protective node is active, the contracts of the machine are opened.

Circuit breaker marking

On the wiring diagrams, the double circuit breaker is marked with unified designations.The icons on the body of the device allow the consumer to obtain complete information about the model:

• Manufacturer - the brand name is indicated.
• Series - alphanumeric designation depends on the manufacturer's line.
• Time-current characteristic - the most common are B, C, D. In conditions of active inductive load and working electronics, models K and Z are used.Universal household appliance - C.
• Rated current - the maximum current value at which the device will not turn off the network. For example, at a temperature of +30 degrees, models of 16 A are used, with an increase in the temperature regime, the rated current may be less than 16 A.
• Rated voltage - marked as V / V, it can be constant ("-") or variable ("~").
• The limiting breaking current is the limit of short-circuit currents in Amperes that the difavtomat can withstand.
• Current limiting class - class 1 (no marker, 10 ms), class 2 (6-10 ms), class 3 (2.5-6 ms). The marker is in the form of a number in a black square.
• The connection diagram is another difference between single-pole and double-pole systems. In the first case, the numbers 1 (top) and 2 (bottom) are used to designate contacts. In the second - 1 and 3 (top), 2 and 4 (bottom);
• Article - barcode or QR code provides the choice of a specific model in the manufacturer's catalog.

By marking the voltage, you can find out for which network the device is suitable. 230 / 400V ~ - for single-phase type, 400 / 400V ~ - for three-phase type.

Possibilities and purpose of multi-pole circuit breakers

The AB installation with two poles is designed to provide control of:

• independent lines - in case of malfunctions, they are simultaneously turned off;
• indicators of each of the lines - in the presence of faults, both are turned off;
• networks with direct current - the reasons for the shutdown are similar.

The input device will turn off the voltage in the entire apartment or house if failures have appeared in at least one area. The bag is convenient because de-energizing can be done manually.

Device assignment

For a single-circuit circuit with single-phase wiring (grounded zero, neutrals are short-circuited on neutral buses), a two-pole is not suitable. In this case, a single-pole switch is installed.

If it is impossible to implement the connection of several devices to a common network, use a two-pole. The machine is installed because there is no neutral and phase at the transformer terminal. Electric current, being cut off on one wire, may remain on the other. The two-pole device replaces the differential protection and RCD systems, which eliminates the cost of purchasing discrete devices.

The four- and three-phase models function in a similar way.

PUE is allowed to install a 2-pole circuit breaker at the input, but an earthing cable cannot be connected to it.

Cons of double-pole circuit breakers

Multi-pole power line protection devices have several disadvantages:

• breakdown of the cable by electric current when two networks are closed at the same time;
• power off throughout the wiring in case of failure of the thermal release;
• the impossibility of turning on the power after fixing the AV in case of an emergency breakdown along one line;
• sensitivity to mechanical damage.

Despite the list of negative properties, models for providing control on two lines are popular. They ensure the safety of the general network in the event of breakdowns on the line to which high-power equipment is installed.

Installation and connection diagrams

The two-pole circuit breaker is installed in accordance with the electrification plan. The body of the device is checked for damage and deformation before installation. The shutdown handle should work well when manually started. Installation is carried out only on a flat surface.

In the process of work, take into account:

• type of connection of copper conductors with a cross section of 16-25 mm2 - by means of cable lugs (GOST 9688-82);
• features of connecting aluminum cables - with end pieces similar to TAM-7 (GOST 9581-80);
• connection of conductors from a power source - to the upper group of stationary switches without effort on automatic clamps;
• termination of conductors - carried out using insulating tubes and protective tape;
• the minimum distance from the metal assemblies of the distribution equipment is from 30 to 50 mm from the top, from 5 to 10 mm from the side;
• possibility of placement in an additional box - a flap without a cover, the entry of the drive unit is checked.

After installation, check the bipolar connection for the quality of switching on and off.

Used schemes

The machine is installed on a din rail. The latch bracket at the top of the case is removed with a flat screwdriver, then the device is placed on the rail and the fasteners are released.

During installation, a standard scheme is used:

1. An input switch is placed in front of the counter.
2. After the meter with input for one phase, a two-pole device is mounted.
3. From above, the input of zero and phase is connected, from the bottom, the cores are diverted into the circuit.

To combine several devices, copper wire jumpers are used. Their ends are cleaned with a sharp object, crimped with a crimper. The second option is to tin the ends with tin and rosin using a soldering iron.

Tighten the bolts firmly to avoid damaging the wiring when heated.

How to choose a two-pole

To choose a good protective device, you should focus on the cross-sectional area of ​​the connection wire. To do this, you need to calculate the value.

First, you should calculate the power and current of the equipment on the power line from the machine. For the current in the circuit, the formula I = P / 220 is used, where 220 is the rated voltage, I is the current (A), and P is the power (W).

Next, select the type of wire, referring to the table.

Based on the data obtained, you can choose an automatic machine taking into account the thermal inertia during heating.

The current in the wires must be greater than the current of the difavtomat, and the latter must be greater than the current load.

Safety measures when installing two-pole circuit breakers

Install a two-pole circuit breaker in accordance with the safety instructions:

• Work together with an assistant to control the process.
• Install the device only after permission from the housing office, Energonadzor.
• Protect your hands with rubber gloves, stand on a rubberized mat.
• Installation is carried out on a DIN rail or shield.
• The attachment point must not be damaged.
• The supply cable to the protection device should be fixed to fixed contacts.
• Before installation, turn off the electricity in the apartment, check the voltage with a multimeter or a screwdriver.

A two-pole circuit breaker creates reliable protection for power lines, equipment in the event of an overcurrent during a short circuit. Understanding the purpose, design features and adhering to the installation scheme, you can secure household appliances and complex industrial equipment.