Your consumer unit — commonly called the fuse box — is the central hub of your home's electrical installation. It receives the electricity supply from the meter and distributes it to individual circuits throughout the property, with each circuit protected by its own circuit breaker or fuse. Understanding the components inside helps you identify what has tripped and what action to take.
The main switch is the large switch at the left-hand end of a modern consumer unit. Switching this to off isolates the entire installation from the supply — useful when doing work on the installation or in an emergency. The main switch does not isolate the meter tails (the cables connecting the meter to the consumer unit), which remain live.
Miniature Circuit Breakers (MCBs) are the individual switches protecting each circuit. They are labelled — or should be — with the circuit they protect (e.g., "Kitchen ring main", "Upstairs lighting"). An MCB that has tripped will be in a different position from the others. RCDs are the wider devices, usually covering multiple MCBs each. They protect against electric shock by detecting very small fault currents. If an RCD trips, it will take out all the circuits it covers at once.
Some modern consumer units use RCBOs — combined MCB and RCD in one device — which means each circuit has individual RCD protection. This means a fault on one circuit trips only that circuit, not a whole group. If your consumer unit is more than 15–20 years old, or has rewirable fuses rather than MCBs, contact DP Power Solutions for a free assessment.
About DP Power Solutions: We are qualified domestic electricians based in Staffordshire, providing EICRs, consumer unit upgrades, rewires, EV charger installation, and more across Cannock, Rugeley, Lichfield, Stafford, and the surrounding area.