News - What Is a Residual Current Circuit Breaker (RCCB)?

What Is an RCCB?

An RCCB, or Residual Current Circuit Breaker, is a safety device installed in an electrical distribution board. It monitors the balance of current flowing through the live and neutral conductors. Under normal conditions, the current that leaves a circuit is equal to the current that returns. When leakage occurs—because of damaged insulation, moisture, or accidental contact with a live part—a difference appears between the two currents.

The RCCB device detects this imbalance and trips, disconnecting the power supply within milliseconds. Because it responds to leakage currents as low as 5–30 milliamperes, it acts before an earth fault can become life-threatening. This is what makes an RCCB device such a vital part of any modern electrical system.

How Does an RCCB Work?

Inside every RCCB is a sensitive current transformer that continuously compares the current in the live conductor with the current in the neutral conductor. When the two are equal, the device remains closed and power flows normally. The moment a leakage current appears, the difference between the two conductors triggers the tripping mechanism, and the breaker opens to cut the supply.

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Detects small leakages that ordinary MCBs cannot sense.
Acts quickly to minimise the risk of injury and fire.
Resets easily after the fault is corrected, allowing fast restoration of power.

Key Functions and Advantages of RCCB

1. Protecting Human Life The primary function of an RCCB is to secure human life. A leakage of just 30 mA can be dangerous, and higher currents can be fatal.

2. Fire Prevention Earth leakage frequently causes overheating and sparks. An RCCB detects early signs of leakage, significantly reducing fire risks.

3. Fast and Reliable Tripping Modern RCCB devices operate within milliseconds. Speed and sensitivity are priorities in every design.

4. Cost-Effective Safety Affordable, easy to install, and simple to maintain—offering high-value protection at a low cost.

5. Flexible System Design: RCCB protected circuits can be combined with MCBs and RCBOs. When both overcurrent and residual-current protection are required, RCBO protection provides a compact solution.

Introducing the CJL1-125 Residual Current Circuit Breaker

Manufactured by Zhejiang C&J Electrical Co., Ltd., the CJL1-125 is a new-generation breaker engineered for residential, commercial, and industrial applications.

(1) New-Generation Plastic Operating Mechanism: More stable and reliable than traditional metal structures, with reduced wear and greater consistency.

(2) All-Copper Current-Carrying Parts: Ensures low resistance, efficient heat dissipation, and dependable conductivity.

(3) Sealed Screw Holes for Greater Safety: Prevents tampering and protects end users with plastic covers.

(4) Large Transparent Signboard: Ideal for panel builders to make clear circuit identification marks.

(5) Advanced Tripping Structure: Higher operational safety and more reliable performance when it matters most.

Technical Data of CJL1-125

Parameter	Specification
Rated Current	16A, 20A, 25A, 32A, 40A, 50A, 63A, 100A, 125A
Rated Voltage	230V (1P+N), 400V (3P+N)
Number of Poles	2P, 4P
Circuit Type	AC type, A type, B type
Breaking Capacity	6000 A
Rated Residual Operating Current	10, 30, 100, 300 mA
Mounting	35 mm DIN Rail
Standard	IEC 61008-1 / IEC 61008-2-1

Application Scenarios

Residential: Kitchens, bathrooms, and outdoor sockets.
Commercial: Offices, shops, and public facilities.
Industrial: Machinery and production lines.
Renovation: Upgrading older installations to modern standards.
OEM Projects: Ideal base for electrical brands.

Why Choose C&J Electrical?

Zhejiang C&J Electrical Co., Ltd. is a professional manufacturer of low-voltage electrical products, supporting a complete range of configurations.

OEM/ODM Brand Customisation: Custom specifications and packaging under your brand.
Multiple Specifications: Wide range of currents and poles for different markets.
High Safety Performance: Tested to international standards (IEC 61008-1).
SKD Shipping: Support for semi-knocked-down delivery to reduce freight costs.

Post time: Nov-03-2026