Switches and disconnectors

Circuit breakers, disconnectors

Circuit breakers and disconnectors are a large group of electrical devices which, having some common features, differ from each other in terms of their structure and functionality. Together with disconnectors, circuit breakers and disconnectors fall into a common category of switches designed to connect electrical circuits in their own way.

Circuit breakers and disconnectors in networks and installations

Circuit breakers are equipped with extinguishing chambers, which enable them to switch off overcurrents, while disconnectors are used to disconnect operating currents with a maximum intensity equal to the rated intensity. Switch disconnectors are not suitable for breaking overcurrents. In order to categorize circuit breakers, various criteria can be adopted, e.g. electric power or the medium used to extinguish an electric arc.

Molded case circuit breakers

Molded case circuit breakers are also called power circuit breakers. They are used in circuits whose receivers are characterized by high electrical power. They are used to control the flow of power in an electrical installation (mainly industrial) or network, as well as protect other circuits and devices against the effects of short circuits and overloads. Molded case circuit breakers are characterized by several parameters:

1. rated voltage,
2. rated current,
3. short-circuit current,
4. permissible operating temperature,
5. way to extinguish the arc.

Circuit-breakers can be classified according to their voltage into low, medium and high voltage. In turn, taking into account the method of extinguishing the arc, we distinguish, among others air circuit breakers , sulfur hexafluoride, vacuum or pneumatic. Usually, the specific method of arc extinguishing is related to the voltage at which the circuit breaker works, but now the division is not as obvious as it used to be. Today you can buy, for example, an air circuit breaker of both high and low voltage.

Circuit breakers, switch disconnectors and disconnectors, or electrical switches

Switches are electrical devices that are used to transfer operating currents as well as short-term overload and short-circuit currents. They include:

1. disconnectors,
2. disconnectors,
3. switches.

Disconnectors are devices that do not have the ability to turn on and off the electricity - they are used to increase the safety of works with power devices. The disconnectors can switch operating and overload currents, but they cannot switch short-circuit currents. On the other hand, the circuit breakers (which include not only the compact circuit breakers described above) can switch on and off the operating, overload and short-circuit currents.

The most popular electrical connectors

The most frequently used switches in residential and industrial installations include screw and panel switches, as well as overcurrent circuit breakers (abbreviated as redundant), i.e. popular, commonly used so-called Modular construction, usually manufactured for rated currents from 0.3 A to 63 A, rated alternating current voltages of 230 and 400 V and direct current voltages of 60 and 110 V, as well as rated short-circuit capacity of 10kA. Selective switches are also important in electrical installations, as they ensure the selectivity of protections in relation to the overcurrent switches located behind them (from the power supply side).

Another group are motor circuit breakers , which are designed to protect motors against the effects of overcurrents (overloads or short circuits). They enable manual switching on and off, while switching off, as in the case of other switches - is also always automatic. A separate group consists of residual current devices, most often in the form of residual current blocks.

Manual switches are another category, which includes, for example, manual panel disconnectors, but also RIN or FR type switches, as well as cam switches . The latter are intended for switching on and off operating currents occurring during the control and connection of motors and other electrical receivers. Next in the category of switches are mechanical switches, contactors and finally installation fuses.