RCBO – stands for Residual Current Breaker with Over-Current’. It basically combines the functionality of an RCD (residual current device) and MCB (miniature circuit breaker). A RCBO is a life-saving device which is designed to prevent you from getting a fatal electric shock if you touch something live, such as a bare wire. … and offers a level of personal protection that ordinary fuses and circuit-breakers cannot provide.
An RCBO constantly monitors the electric current flowing through one or more circuits it is used to protect. If it detects electricity flowing down an unintended path, such as through a person who has touched a live part, the RCBO will switch the circuit off very quickly, significantly reducing the risk of death or serious injury.
RCBOs can help protect you from electric shock in potentially dangerous areas like bathrooms and gardens, and there are various types of RCBOs that can be used to make sure you are always as safe as possible.
RCD – known as Residual Current Device. Similar to a RCBO and it’s purpose is the same- to protect you against the risks of electrocution and fire caused by earth faults. Another example, if you cut through the cable when mowing the lawn and accidentally touched the exposed live wires or a faulty appliance overheats causing electric current to flow to earth.
SPD – Surge Protection Device. Used to protect the electrical installation, which consists of the consumer unit, wiring and accessories, from electrical power surges known as transient overvoltages.
They are also used to protect sensitive electronic equipment connected to the installation, such as computers, televisions, washing machines and safety circuits, such as fire detection systems and emergency lighting. Equipment with sensitive electronic circuitry can be vulnerable to damage by transient overvoltages.
The effects of a surge can result in either instant failure or damage to the equipment only evident over a longer period of time. SPDs are usually installed within the consumer unit to protect the electrical installation but different types of SPD are available to protect the installation from other incoming services, such as telephone lines and cable TV. It is important to remember that protecting the electrical installation alone and not the other services could leave another route for transient voltages to enter the installation.