Основный справочник по выключателям: понимание их функций и типов

Release Time: 2026-06-08

A basic breaker schedule should answer what must be disconnected, why it must disconnect and which device provides each function. Choosing by cabinet size or an abbreviation can leave important protection unassigned.

Circuit-breakers provide declared interruption and protective functions. MCB, АВМ and ACB describe different device categories, while RCCB, RCBO, SPD and isolator labels describe other or combined functions. They are not universal substitutes.

Start with the function

Overcurrent interruption addresses overload and short circuit within the device scope. Residual-current protection detects an imbalance. Surge limitation addresses transient voltage. An isolation function supports a defined separation for maintenance where declared, but safe isolation also requires a procedure.

Device category	Typical function to verify	Important boundary
МКБ	Перегрузка и короткое замыкание	No integral residual-current detection
MCCB or ACB	Declared overcurrent and optional functions	Exact release and fault rating required
RCCB	Residual-current detection	Separate overcurrent protection
RCBO	Combined overcurrent and residual-current	Both function sets need selection
SPD	Transient voltage limitation	Not an overload breaker
Switch-disconnector	Switching and declared isolation	Fault protection may be separate

Руководство по Малелированные выключатели рассказывает, как различаются размер кадров, рейтинг и поведение при поездке.

Facilities engineer reviewing a circuit-breaker schedule in a Singapore commercial plant

Select by circuit duty

Record voltage type, operational voltage, current, poles and потенциальный ток короткого замыкания. Then check conductor protection, load starting and environmental conditions. A current rating does not establish interruption capability, and a high insulation-voltage value does not authorise operation at that voltage.

AC and DC duties need explicit evidence. DC source behaviour, polarity and pole connections cannot be inferred from AC ratings. For an RCBO, specify residual-current type and sensitivity separately from its overcurrent curve.

Используйте Технические требования к МКЦБ проверьте спецификацию по коду заказа и файлу проекта.

Annotated diagram showing overload, short-circuit and residual-current paths through a breaker

Compare the installed arrangement

The complete panel includes busbars, terminals, conductors, enclosure and other devices. Mechanical fit is not assembly acceptance. A proposed replacement must preserve curves, functions, connections and required documents, not just the current printed on its face.

Этап проекта	Decision
Дизайн	Assign each protective and isolation function
Закупки	Freeze exact model and accessories
Сборка	Verify fit, connections and enclosure conditions
Ввод в эксплуатацию	Confirm settings, wiring and required tests
Поддержание работоспособности	Control substitutions and setting changes

Labelled MCB, MCCB, RCCB and RCBO devices in a tested distribution board

Standards and evidence

IEC 60947-2, IEC 60898-1, IEC 61008-1 and IEC 61009-1 cover different product scopes. IEC 61439 addresses low-voltage assemblies, while installation rules and verification add further requirements. A standard reference is not a blanket certificate for every configuration.

For a W9 enquiry, send the circuit schedule and required functions. A clear specification avoids asking one device category to perform a function it does not include.

Часто задаваемые вопросы

What is the basic function of a circuit breaker?

It switches and interrupts within its declared duty and protective functions. Overload and Защита от короткого замыкания must be matched to the circuit and exact release.