Residual-current device

Residential GFCI receptacle

Residual current device 2pole

IEC TS 60479-1 electric shock graph

FISkizze

Schneider Electric A9D31620

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ResidualCurrentCircuitBreak

Residual-current device

A residual-current device (RCD), also known as a residual-current circuit breaker (RCCB), is an electrical safety device that quickly breaks an electrical circuit to prevent serious harm from an ongoing electric shock. RCDs are designed to protect against the risks of electrocution and fire caused by earth faults.

Function

RCDs work by detecting an imbalance between the live and neutral conductors. Under normal circumstances, the current flowing through the live conductor should be equal to the current returning through the neutral conductor. If there is a difference, it indicates that some of the current is flowing through an unintended path, such as through a person or to the ground. When this imbalance exceeds a predetermined threshold, the RCD disconnects the circuit.

Types

There are several types of RCDs, including:

• Fixed RCDs: Installed in the consumer unit (fuse box) and protect individual or groups of circuits.
• Socket-outlet RCDs: Built into a standard socket-outlet to protect the person using electrical equipment plugged into the socket.
• Portable RCDs: Plugged into any standard socket-outlet and then the electrical equipment is plugged into the RCD.

Applications

RCDs are used in various applications, including:

• Residential wiring
• Commercial buildings
• Industrial settings
• Construction sites

Standards and Regulations

RCDs must comply with specific standards and regulations, which vary by country. In many regions, the installation of RCDs is mandatory in certain situations, such as in bathrooms and outdoor electrical installations.

Advantages

• Provides protection against electric shock.
• Reduces the risk of electrical fires.
• Enhances overall electrical safety.

Limitations

• Does not protect against all types of electrical faults, such as short circuits or overloads.
• Requires regular testing to ensure proper functionality.

Maintenance

Regular testing of RCDs is essential to ensure they are functioning correctly. This can typically be done by pressing the "test" button on the device, which should cause it to trip.

See also

• Circuit breaker
• Earth leakage circuit breaker
• Ground fault circuit interrupter
• Electrical wiring
• Electrical safety

Related Pages

• Circuit breaker
• Earth leakage circuit breaker
• Ground fault circuit interrupter
• Electrical wiring
• Electrical safety