A consumer unit, often referred to as a fuse box or distribution board, is an essential component of a domestic electrical system in the UK. It serves as the central point where electricity enters a property and is then distributed safely to different circuits.
What are the different parts of a consumer unit?
Main Switch
The main switch is the most crucial part of a consumer unit. It allows the entire electrical supply to the property to be turned on or off manually. In the event of an emergency, such as an electrical fault or fire, the main switch should be used to cut the power to prevent further damage or risk of electric shock. It is usually positioned at the top or side of the unit for easy access.
Circuit Breakers (MCBs)
Miniature Circuit Breakers (MCBs) protect individual circuits within the home. Each MCB corresponds to a particular area or appliance, such as lighting, sockets, or kitchen equipment. Their role is to automatically switch off the power to a circuit when an overload or short circuit is detected. This prevents overheating, fire, and damage to appliances. MCBs can easily be reset by flicking the switch, unlike traditional fuses which needed replacing.
Residual Current Devices (RCDs)
RCDs are vital safety devices that monitor the electrical current flowing in and out of a circuit. If they detect an imbalance – such as current leaking to earth due to a damaged cable or someone receiving an electric shock – they cut the power almost instantly. RCDs provide protection from electric shocks and are usually fitted to cover multiple circuits. Modern units typically include two RCDs, each protecting a group of MCBs.
RCBOs (Residual Current Breaker with Overcurrent)
An RCBO is a hybrid device that combines the functions of an MCB and an RCD. Rather than relying on separate RCDs to protect several circuits, an RCBO protects both the earth leakage and overload faults on an individual circuit. These are becoming increasingly popular in modern installations as they offer more precise protection and reduce the risk of nuisance tripping across multiple circuits.
Busbar
The busbar is a metal strip inside the consumer unit that distributes electricity from the main switch to the circuit breakers. It is usually made from copper for good conductivity and is hidden behind a cover. The busbar ensures that all breakers receive power evenly and efficiently.
Neutral and Earth Terminal Bars
All circuits need a return path for current (neutral) and a safety path (earth). These are connected to the neutral and earth terminal bars within the unit. Electricians use these terminals when wiring new circuits, and they are essential for the correct and safe operation of the system.
Get a new fuse box fitted by Bot Elec Ltd that will keep your electrics working safely and in line with the latest UK regulations. Choose a consumer unit replacement by one of the Bot Elec Ltd expert engineers, and we’ll give you a free quote that includes:
- All parts and labour
- 12-month warranty
- Fully certified installation
