Difference Between MCB, MCCB, RCB, RCD, RCCB, and RCBO: 2026 Guide

If you are trying to understand the difference between MCB, MCCB, RCB, КОД, RCCB, и RCBO, the short answer is this:

• MCB и MCCB mainly protect against перегрузка и короткое замыкание
• КОД, RCCB, и RCB are mainly used for residual-current or earth-leakage protection
• RCBO combines residual-current protection с защита от перегрузки по току в одном устройстве

That is the core distinction. The confusion usually starts because some of these terms are device names, while others are broader category terms that get used differently across markets.

This guide is designed to make that difference clear, fast, and practical.

Quick Comparison Table

Термин	Full form	Main protection role	What it does not do by itself	Typical use
MCB	Миниатюрный автоматический выключатель	Overload and short-circuit protection	Does not provide residual-current protection	Final circuits, branch protection, residential and light commercial panels
MCCB	Автоматический выключатель в литом корпусе	Higher-capacity overload and short-circuit protection	Does not provide residual-current protection by itself	Commercial and industrial distribution, larger feeders
RCB	Residual Current Breaker	Usually refers to residual-current protection device terminology	Meaning can vary by market and product context	Used loosely in some catalogs or conversations
КОД	Устройство защитного отключения	Broad category for residual-current detection devices	Not always a single exact device type	General residual-current protection language
RCCB	Автоматический выключатель дифференциального тока	Residual-current or earth-leakage protection	Does not provide overload or short-circuit protection	Shock protection where separate overcurrent protection is present
RCBO	Residual Current Breaker with Overcurrent Protection	Combined residual-current, overload, and short-circuit protection	Does not remove the need for correct sizing and coordination	Circuits needing combined protection in one device

For readers who want a device-by-device definition first, VIOX already has supporting pages for MCB full form, Полная форма аббревиатуры MCCB, и Полная форма РЦКБ.

What Each Term Means

Before comparing these devices, it helps to separate overcurrent protection terms От residual-current protection terms.

MCB

MCB означает Миниатюрный автоматический выключатель.

It is mainly used to protect circuits against:

• перегрузка
• короткое замыкание

MCBs are common in residential distribution boards, final circuits, and lighter commercial applications. They are compact, widely available, and commonly selected by current rating, trip curve, breaking capacity, and pole configuration.

If you want the deeper definition page, see Полная форма MCB в электротехнике.

MCCB

MCCB означает Автоматический выключатель в литом корпусе.

An MCCB performs the same core protection role as an MCB, but it is generally used where higher current levels, larger fault levels, or more adjustable protection settings are required.

Typical reasons to use an MCCB instead of an MCB include:

• larger feeder circuits
• industrial panels
• motor or distribution applications with higher fault energy
• need for adjustable trip settings in some designs

For a dedicated definition article, see MCCB Full Form Molded Case Circuit Breaker.

RCB

RCB usually refers to Residual Current Breaker, but this term is less precise than RCCB или RCBO.

In practice, RCB is often used loosely in conversations, older documents, or mixed catalogs. That is why it can create confusion. Some people use it as a generic label for residual-current protection devices, while others use more specific names such as RCCB или RCBO.

So if the question is technical, it is better not to stop at RCB. Confirm whether the device in question is:

• an RCCB
• an RCBO
• or a broader КОД category reference

КОД

КОД означает Устройство защитного отключения.

This is usually the broader category term. It describes devices that monitor imbalance between live and neutral currents and trip when residual current exceeds the device threshold.

That means RCCB и RCBO can both sit within the wider residual-current protection discussion, but they are not identical devices.

RCCB

RCCB означает Автоматический выключатель дифференциального тока.

Its job is to detect residual current or earth-leakage conditions and disconnect the circuit. However, an RCCB does not provide overload and short-circuit protection by itself.

That is one of the most important differences on this page.

RCBO

RCBO означает Residual Current Breaker with Overcurrent Protection.

An RCBO combines:

• residual-current protection
• защиту от перегрузки
• short-circuit protection

in one device body.

That makes it especially useful where designers want circuit-level combined protection without pairing a separate RCCB and MCB for the same final circuit.

For more RCBO-focused reading, VIOX also has Как правильно выбрать АВДТ и Сравнение RCBO и RCCB MCB: пространство, стоимость, селективность.

MCB vs MCCB

The difference between MCB и MCCB is not that one protects and the other does not. Both are used for overcurrent protection. The real difference is application range and capability.

MCB is usually better suited for:

• final circuits
• branch protection
• lighter current applications
• residential and light commercial boards

MCCB is usually better suited for:

• feeders
• larger distribution boards
• higher current applications
• installations that may require wider setting flexibility

MCB vs MCCB Table

Фактор	MCB	MCCB
Typical role	Final circuit protection	Feeder and larger circuit protection
Current range tendency	Нижний	Выше
Setting adjustability	Usually limited	Often broader
Common environment	Жилые и легкие коммерческие помещения	Commercial and industrial
Физический размер	Более компактный	Larger and heavier-duty

For a deeper article focused only on this pair, see MCCB против MCB.

RCB vs RCD vs RCCB

This group creates the most confusion because the names sound similar, but they are not always used at the same level of specificity.

The simplest way to understand them

• КОД is usually the broad category term
• RCCB это specific device type
• RCB is often a loose or less precise label

That means when someone asks about RCD vs RCCB, the answer is often not a direct “better or worse” comparison. It is more a question of category vs specific device name.

Practical interpretation

If a specification, panel schedule, or product catalog says КОД, you should check:

• whether it means a general residual-current protection function
• whether the intended device is actually an RCCB
• whether the project really needs an RCBO instead

This is where poor terminology causes procurement mistakes.

Why RCBO Is Different

An RCBO matters because it bridges the two protection families discussed above.

An MCB protects against overcurrent.
An RCCB protects against residual current.
An RCBO combines both.

RCBO vs RCCB

If you compare RCBO и RCCB, the key difference is simple:

• RCCB needs separate overcurrent protection elsewhere in the system design
• RCBO already includes overcurrent protection

That can affect:

• panel space
• circuit selectivity strategy
• cost structure
• fault isolation at the circuit level

For the deeper version of this comparison, use Сравнение RCBO и RCCB MCB: пространство, стоимость, селективность.

RCBO vs MCB

If you compare RCBO и MCB, the difference is also straightforward:

• MCB = overload and short circuit only
• RCBO = overload, short circuit, and residual current

That does not automatically mean RCBO is always the right answer. It means the protection function is broader, and the application should decide the choice.

How To Choose the Right Device

If the reader is no longer just comparing names, the next question is usually selection.

Selection Table

Ситуация	Usually start by considering	Почему
Standard final circuit overcurrent protection	MCB	Compact and suitable for many branch circuits
Higher-current feeder or industrial distribution	MCCB	Better suited to higher-capacity applications
Leakage protection with separate overcurrent device	RCCB	Residual-current protection role
Combined leakage and overcurrent protection on one circuit	RCBO	Brings multiple protection functions into one device
Residual-current terminology in a broad sense	КОД	Category term, not always the final device choice

Questions to ask before choosing

• Is the main need overcurrent protection, residual-current protection, or both?
• Is this a final circuit or a larger feeder circuit?
• What is the expected fault level?
• Is panel space limited?
• Does the design require circuit-level isolation instead of grouping many circuits under one residual-current device?
• What do local rules, project specifications, and manufacturer instructions require?

Распространенные ошибки, которых следует избегать

These are the mistakes that cause the most confusion in real projects:

1. Treating RCD, RCCB, and RCB as fully interchangeable

They are closely related terms, but not always exact substitutes. Category language and device naming should be checked carefully.

2. Assuming RCCB provides overcurrent protection

It does not. An RCCB focuses on residual-current protection and must be used within the correct protection architecture.

3. Choosing MCB when combined protection is needed

If the circuit needs both residual-current and overcurrent protection in one device, an MCB alone is not enough.

4. Using RCBO as a blanket default without checking application fit

An RCBO is powerful, but selection still depends on circuit design, rating, residual-current sensitivity, breaking capacity, and coordination.

5. Ignoring the difference between MCB and MCCB current/application range

These devices overlap in concept, but not always in the same application window.

Which Article Should the Reader Open Next?

If the reader still needs definitions:

• Полная форма MCB в электротехнике
• MCCB Full Form Molded Case Circuit Breaker
• RCCB Full Form Understanding Residual Current Circuit Breakers

If the reader needs comparison:

• MCCB против MCB
• Сравнение RCBO и RCCB MCB: пространство, стоимость, селективность
• RCBO vs AFDD Difference Guide

If the reader needs selection:

• Как правильно выбрать АВДТ
• Как выбрать MCCB для панели

ЧАСТО ЗАДАВАЕМЫЕ ВОПРОСЫ

В чем основное различие между MCB и MCCB?

Both protect against overload and short circuit, but MCCBs are generally used for larger and higher-capacity applications, while MCBs are commonly used for final circuits and lighter distribution.

What is the difference between RCD and RCCB?

RCD is usually the broader category term, while RCCB refers to a more specific residual-current circuit breaker device.

Is RCB the same as RCCB?

Not always. RCB is often used as a loose or simplified term, while RCCB is a more precise device name.

What is the difference between RCCB and RCBO?

An RCCB provides residual-current protection only, while an RCBO combines residual-current protection with overload and short-circuit protection.

Is RCBO better than MCB?

Not in every application. An RCBO provides broader protection than an MCB, but the correct choice depends on the protection objective, circuit design, and installation requirements.