“Residual Current Circuit Breakers (RCCBs), also known as Residual Current Devices (RCDs), are electrical safety devices designed to protect against electrical shock and fire hazards caused by ground faults or leakage currents. These devices are commonly used in electrical installations to provide an additional layer of protection beyond traditional circuit breakers or fuses.
Here’s how RCCBs work:
Sensing Current Imbalance: RCCBs continuously monitor the current flowing through the live (hot) and neutral wires of an electrical circuit. A residual current occurs when there’s an imbalance between the current flowing into the circuit through the live wire and the current returning through the neutral wire. This imbalance could be due to a ground fault, such as a person coming into contact with a live wire or a fault in an appliance.
Tripping Mechanism: When an RCCB detects a significant imbalance in current, typically around 30 milliamps (mA) or more, it quickly opens the circuit by tripping its internal switching mechanism. This rapid action helps prevent potentially dangerous electric shocks or fires that could result from a ground fault.
Protection Levels: RCCBs come in different sensitivity levels, known as trip currents. Common trip currents include 30 mA, 100 mA, and 300 mA. The choice of sensitivity depends on the specific application and the potential risks associated with the electrical installation.
Types of RCCBs: There are two main types of RCCBs:
Type AC: These are designed to detect alternating current (AC) ground faults. They are suitable for most residential and general-purpose applications.
Type A: These are more sensitive and can detect both AC and pulsating direct current (DC) ground faults. They are used in situations where there might be electronic equipment or appliances with rectifiers that produce pulsating DC leakage currents.
RCCBs play a crucial role in electrical safety by quickly disconnecting the power supply when a ground fault occurs, thus reducing the risk of electrical shock and fires. They are commonly used in residential, commercial, and industrial settings, especially in areas where people are likely to come into contact with electrical equipment or in environments where moisture and other factors increase the risk of ground faults.”