The C32 circuit breaker is a circuit breaker that protects the network from overloads and short circuits. Also designed to turn on and off the load currents manually. The machine is modular because consist of separate single-pole blocks that can be used as single-phase or combine several into two-or three-phase. This design makes it easy to assemble the required apparatus of the required configuration. In the event of a breakdown, a single damaged element can be replaced.
General characteristics and marking of C32 circuit breakers
Many characteristics of the circuit breaker are indicated on its case. The main one is the rated current. This is the maximum current that the device passes in normal mode and for a long time. For a C32 machine, it is 32 Amps.
Another important characteristic is the ability of the protective device to disconnect short-circuit currents of a certain value (switching). After operation, the device should remain fully operational. Short circuit current is usually indicated in a rectangular box. For a 32 Ampere machine, it is 4500 A, or 6500 A.
In industrial devices, additional characteristics are used:
- ultimate breaking capacity Icu - double operation current, not incapacitating the device;
- operating breaking capacity Ics - triple trip current.
The higher the breaking capacity, the more reliable and durable the device.
In the process of disconnecting a short circuit between the contacts of the switch, an electric arc flashes. It has a high temperature and is capable of destroying the apparatus. It goes out with the help of interrupter chambers. The faster this happens, the higher the current limiting class of the device:
- for the first class - above 10 milliseconds;
- for the second - less than 10 milliseconds;
- for the third class - from 3 to 6 milliseconds.
This characteristic is marked with numbers 2 or 3 in a square frame. If there is no such marking, this is a class 1 machine.
During operation in the electrical network, transient current or load surges may occur. This is due, for example, to turn on or off powerful power consumers. May lead to false positives. To avoid this situation, time-current characteristics are used: the ratio of the tripping current to the trip time.
In any machine there are two automatic disconnecting elements.
- Electromagnetic release. Designed to trip when short-circuit currents occur. It is driven by a current relay.
- Thermal release. It works during heating due to overload of the protected area. Based on the work of bimetallic contact.
Time-current characteristics are calculated for each separately. They are indicated by Latin letters A, B, C, D and are indicated together with the rated current. With a C32 machine, this is characteristic “C”.
In order to protect against overload currents, the thermal release is set to certain values. For the C32 circuit breaker, the time-current characteristic is 1.13-1.45 of the rated current. This means that a device with a nominal value of 32 Amperes will turn off after an hour at a current of 1.13 × 32A = 36.2 Amperes. With a flow of 1.45 × 32 = 46 Amps, it will turn off in less than an hour. With an increase in overload, the shutdown speed will decrease until the electromagnetic release starts to operate.
The electromagnetic release C32 will be triggered when the current increases above the nominal 5 times - after 0.1 seconds; if the current exceeds the rated 10 times, faster than 0.1 seconds.
Cross section of wires and cables
The wire section for the machine at 32a is also selected according to the time-current characteristics. A copper core with a cross section of 6 mm and an aluminum core of 10 mm withstands overloads up to 42 Amps for a long time. With an increase in the load, the conductors will heat up, but here the protection of the machines starts, so such modes are short-lived and can be ignored.
Rated voltage and load power
Thanks to the modular design, the 32 amp machine can be assembled into blocks of various configurations. In a single-phase circuit, it can be single or bipolar. In a three-phase at 380 volts - three-pole and four-pole. Bipolar can be used in a two-phase circuit, but such networks are infrequently used. Protection is usually installed on phase conductors. When installed on phase with zero (2-pole and 4-pole) switches are mechanically connected for simultaneous shutdown.
The 32 A automatic machine is designed for an alternating current voltage of ∼230 / 400 V. The device is able to work for a long time at a given level. When using one pole, the rated voltage is 230 volts. When used in a two- or three-phase circuit, when the modules are combined into multipolar devices - 400 volts.
The load power is calculated by the formula P = U × I, where P is the power, U is the mains voltage, I is the rated current. For a single-phase network of 230 Volts × 32 Amperes, we get 7360 Watts.
A 32-pole three-pole circuit breaker is calculated for a three-phase network: 400 Volt × 32 Amperes = 12800 Watts. Since the voltage values are averaged, the load must be selected 10% less than calculations: 7 kW for one phase, 12 kW for three.
The use of automatic machines C32
A 32 amp automatic machine is installed in residential and administrative buildings. Mixed load, heating and lighting devices, household appliances and electronics - the main scope of their application. With the protection of household appliances and electronics do an excellent job. They are used as input - installed up to meters, or as protection of individual consumers.
Through C32 devices, it is not recommended to turn on powerful electric motors, even if they are suitable for the load. The time-current characteristic “C” indicates that protection can be triggered spuriously from inrush currents.
Wiring diagram
The wire supplying the switch is connected to a fixed contact, which is usually located on top. The wire to the power receiver is attached at the bottom. To avoid confusion, an elementary diagram with the designation of contacts is drawn on the case. They are signed with the numbers 1-input, 2-output. In the three-phase version, it is similar: even - supply contacts, odd - outputs.
In modern electrical installations, together with automatic machines, additional devices are used: RCD (residual current device), additional contacts, load switches, automatic switching devices. For reliable operation, it is recommended to install devices of the same series from one manufacturer.
The choice of manufacturers of protective devices is huge. Domestic enterprises can offer reliable equipment, but the range is extremely narrow. The production of additional devices is a rarity. Among foreign companies, ABB stands out, which has a serious scientific and technical base. Also noteworthy are such brands as Legrand, Siemens, GE, Schneider, Electric, Hager. The choice of equipment should be carried out for a specific project, looking at the assortment, which is often limited.
