Upgrading your Consumer Unit: Why its best to fit RCBOs over RCDs?

In England, RCDs (Residual Current Devices) and RCBOs (Residual Current Breaker with Overcurrent Protection) are both types of electrical safety devices designed to protect against electric shocks and fires. While they serve a similar purpose, there are some key differences between the two.

1. Functionality:

   • RCDs: An RCD is a safety device that detects imbalances in electrical currents. It quickly interrupts the circuit if it detects a leakage of current, such as when a person accidentally comes into contact with a live wire. RCDs provide protection against electric shock.

   • RCBOs: RCBOs combine the functions of an RCD and a miniature circuit breaker (MCB) in a single device. In addition to providing protection against electric shock caused by current leakage, RCBOs also offer overcurrent protection. This means they can detect and interrupt the circuit if the current exceeds a certain threshold, which helps safeguard against electrical fires caused by overloaded or short-circuited circuits.

2. Installation:

   • RCDs: RCDs are typically installed in the distribution board or consumer unit and provide protection for multiple circuits. They are connected to the main incoming electrical supply and monitor the overall current imbalance for all the connected circuits.

   • RCBOs: RCBOs are individual devices that combine the functions of an RCD and an MCB. They are installed in the distribution board or consumer unit for each individual circuit. This allows for selective protection, meaning that if a fault occurs in one circuit, only that circuit will be affected, and the rest of the circuits will remain operational.

3. Selectivity:

   • RCDs: As RCDs protect multiple circuits, they do not offer selectivity. If a fault occurs in one circuit, the RCD will trip and interrupt the power supply to all the connected circuits.

   • RCBOs: RCBOs provide selectivity because they are installed on individual circuits. If a fault occurs in a specific circuit, only the RCBO protecting that circuit will trip, while the rest of the circuits will remain unaffected.

4. Application:

   • RCDs: RCDs are commonly used for general protection against electric shock hazards in residential, commercial, and industrial installations.

   • RCBOs: RCBOs are often used in situations where individual circuit protection with both overcurrent and electric shock protection is desired, such as in areas with specific electrical equipment or appliances that require dedicated protection.

It's important to note that regulations and standards regarding electrical installations may vary from country to country. The information provided here specifically pertains to England, but it's always advisable to consult local regulations and seek professional advice for specific electrical installations and requirements.