Consumer Units

What is a Consumer Unit? 

Also known as a fuse board or fuse box, a consumer unit is designed to distribute electricity from the main supply around a building to individual circuits. It plays a hugely important role within your property, safely regulating the electrical supply and minimising the risk of danger to you and your home.  

How Does a Consumer Unit Work? 

A consumer unit acts sort of like a control centre for your property’s electrical supply. Each circuit is carefully monitored so that if and when any overloads are detected, the system is tripped to avoid damage and danger such as fire or electric shock. The distribution board incorporates several specialist components such as the main switch which is used to turn the power on and off manually should you need to safely isolate the electrical supply.  

Main Switch 

The job of the main switch is to supply the consumer unit with electricity from the meter. When the switch is turned OFF, the consumer unit becomes isolated and the supply of electricity to your property and its devices is cut off – useful for emergencies or maintenance repairs. 

RCD – Residual Current Device 

This special set of switches monitors all of the electrical currents within your property. The RCDs automatically switch off (also known as tripping) when the power flow is imbalanced which helps to prevent electric shock and fires. 

MCB – Mini Circuit Breaker 

The MCB is the port to which the electrical circuits connect. MCBs also switch off automatically but instead due to an overload of power (potentially caused by too many devices plugged into one circuit) or an overcurrent which is produced when the circuit has a defect.  

RCBO – Residual Current Breaker & Overload 

In simple terms, the RCBO combines the function of an RCD and MCB to prevent overloads, overcurrents and electric shock whilst also reducing the risk of tripping. 

SPD – Surge Protection Device 

Although not always a necessary component, an SPD can be installed by your electrician if needed to provide an extra layer of protection over the electrical system and the equipment you connect to it.  

AFDD – Arc Fault Detection Device 

AFDDs are specialist protective components that are fitted into consumer units to protect against arc faults and reduce the risk of fire. An arc is created when the electrical current jumps the gap between two conductive materials and can be caused by a breakage in cable, damaged insulation, loose connections etc.