RCCBs

An RCCB, or residual current circuit breaker, is a critical safety device engineered to protect electrical circuits from hazardous conditions. These essential circuit breakers safeguard individuals from electric shocks and electrocution, simultaneously helping to prevent electrical fires caused by fault currents.

RS Australia offers an extensive range of high-performance RCCBs, designed to ensure superior safety in various installations.

How Does a Residual Current Circuit Breaker (RCCB) Work?

A residual current circuit breaker constantly monitors the electrical current flowing through a circuit to detect imbalances. Its fundamental operation relies on the principle that, in a healthy circuit, the incoming current on the live wire must equal the outgoing current on the neutral wire.

The RCCB circuit breaker continuously compares the current values in these two wires. When appliances function correctly, all current entering through the live wire exits via the neutral wire.

However, if a fault occurs – such as a person touching a live component or a faulty appliance leaking current to earth – some current will divert from its intended path. This creates a difference between the incoming and outgoing currents, known as a residual current.

If this residual current exceeds a predetermined safe level, the RCCB rapidly trips, instantly cutting off the power supply and preventing electric shock or fire.

What is the Difference Between an RCCB and an RCD?

A residual current device (RCD) is a vital safety component designed to prevent fatal electric shocks by automatically switching off electricity when a current imbalance is detected.

An RCCB is a type of RCD – while all RCCBs are RCDs, not all RCDs are RCCBs. Here are some of their key differences:

Overload Protection

Unlike RCDs, a standalone RCCB does not inherently offer overload protection. This means it will trip on earth leakage but will not protect against excessive current flowing due to an overload or short circuit.

For comprehensive protection, an RCCB typically needs to be paired with a miniature circuit breaker (MCB) to handle overcurrents.

Use Case

RCCBs are ideal for applications solely requiring earth fault protection, often when combined with MCBs for full circuit safety.

RCDs, in broader terms, include devices like RCBOs (Residual Current Breaker with Overcurrent protection), which offer a more integrated solution for both earth fault and overload protection, streamlining electrical system designs.

Types of RCCB

By Number of Poles

RCCBs are typically mounted on DIN rails and are available with varying numbers of poles, each designed for specific circuit configurations:

Single-pole RCCB: Protects a single phase circuit, often used in lighting or small appliance circuits.
Two-pole RCCB: Provides protection for single-phase circuits with both live and neutral conductors. The 2-pole RCCB is common for residential and light commercial setups.
Three-pole RCCB: Designed for three-phase electrical systems without a neutral conductor.
Four-pole RCCB: Offers protection for three-phase electrical systems that include a neutral conductor, providing comprehensive safety.

By Current Ratings

RCCBs are also available with various current ratings, designed to trip at different levels of residual current for specific protective purposes.

Lower ratings like 10mA are more sensitive, used for critical personal protection in residential settings. Meanwhile, higher ratings from 300mA are suitable for fire and equipment protection in commercial and industrial installations.

Here are some common ratings that ensure appropriate sensitivity to fault currents:

10mA
30mA
100mA
300mA
500mA
1000mA

By Trip Sensitivity

Trip sensitivity refers to how quickly an RCCB responds to different types of residual currents. This variety ensures optimal protection for diverse load characteristics.

Type A: Detects AC and pulsating DC residual currents, suitable for use with all types of appliances.
Type A-HI: High immunity against nuisance tripping from sinusoidal alternate and pulsating currents.
Type A-SI: Superior immunity for high frequency currents and electromagnetic disturbances, suitable for harsh environments.
Type AC: Detects only AC residual currents. Only suitable for applications that do not contain electronic parts that may produce DC faults
Type B: Detects AC, pulsating DC, and smooth DC residual current faults.
Type B-EV: Specifically for electric vehicle charging applications.
Type B-SI: High immunity for smooth DC residual currents.
Type C: Similar to Type A but with specific time-delay characteristics.
Type F: Covers the capabilities of A and AC types, but with ability to sense frequencies other than the standard 50/60Hz.

Industrial Applications of Residual Current Circuit Breakers

RCCB circuit breakers are fundamental safety devices employed across a wide spectrum of industries to protect personnel and equipment from electrical hazards.

Manufacturing Facilities

In manufacturing facilities, RCCB breakers are vital for protecting personnel operating machinery and preventing electrical fires.

They detect earth faults caused by damaged wiring or equipment, rapidly disconnecting power. High-sensitivity 30mA RCCBs are commonly deployed for general safety.

Commercial Buildings and Offices

Commercial buildings utilise RCCBs to enhance safety in areas with numerous electrical appliances and high occupancy.

They provide critical protection against indirect contact, safeguarding occupants from electric shocks. Type AC RCCBs are frequently installed in these environments for standard protection.

Construction Sites

Construction sites present significant electrical risks. As such, RCCBs are indispensable for protecting temporary power supplies and portable equipment from earth faults and insulation breakdowns.

Food and Beverage Industry

The food and beverage industry requires stringent electrical safety due to wet environments and frequent cleaning processes.

RCCBs with higher IP ratings and suitable trip sensitivities are crucial for protecting workers from shocks and preventing equipment damage from moisture-related faults.

Medical and Healthcare Facilities

In medical and healthcare facilities, RCCBs are paramount for patient and staff safety, especially in areas with critical life-support equipment.

Highly sensitive RCCBs like 10mA breakers, are used to prevent minute leakage currents from causing harm, ensuring a safe electrical environment for sensitive procedures.

Buy RCCBs from RS Australia

RS Australia is a trusted supplier and distributor of RCCBs, offering a comprehensive selection of these vital safety devices at competitive prices. Our products are sourced from reputable brands such as Hager, ABB, Schneider Electric, and Siemens, ensuring high-quality options for every customer.

Beyond residual current circuit breakers, we also provide a wide array of other electrical components, including fuses and moulded case circuit breakers, to meet all industrial electrical safety needs.

Browse our user-friendly online site to explore the full range of products and have your items shipped right to your door. With our flexible delivery options, we ensure you receive your products at your convenience.

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