What is an RCBO? The Complete Guide
RCBO stands for Residual Current Breaker with Overcurrent protection. It's the modern, safest way to protect every circuit in your home — and the standard we install on every consumer unit upgrade across Devon.
RCBO meaning in plain English
An RCBO is one device that does the job of two: it cuts the power if a circuit draws too much current (like an MCB / fuse), and it cuts the power if electricity is leaking to earth (like an RCD). One RCBO protects one circuit.
RCD or RCBO — what's the difference?
RCD (older / cheaper)
One RCD covers a group of circuits.
A single fault — say, a broken kettle — trips the RCD and kills power to half the house. Fridge off, lights off, alarm off.
RCBO (what we fit)
One RCBO per circuit.
A fault on the kettle circuit trips only the kitchen sockets. Everything else stays on. Easier to fault-find, safer for vulnerable users, and required by modern wiring regs on most installs.
Why is my RCBO tripping?
- Faulty appliance leaking current to earth (kettles, washing machines, immersion heaters)
- Water ingress into outdoor sockets, garden lights or shed wiring
- Damaged cable — nail through a wall, rodent damage, age-related insulation breakdown
- Overloaded circuit drawing more current than the RCBO rating
- A failing RCBO at the end of its working life (typically 15–20 years)
Need an RCBO board fitted or fault-found?
Full RCBO consumer units from £650 plus VAT. Same-week appointments across Devon.
Frequently Asked Questions
What is an RCBO?
An RCBO (Residual Current Breaker with Overcurrent protection) is a single device that combines the protection of an MCB (overload/short circuit) with an RCD (earth leakage). One RCBO protects one circuit, so if a fault occurs only that circuit trips — the rest of the house keeps working.
What does RCBO stand for?
RCBO stands for Residual Current Breaker with Overcurrent. It is a protective device installed in your consumer unit (fuse board) that protects both people from electric shock and the wiring from overload.
RCD or RCBO — which is better?
RCBOs are better than dual RCD boards. With a dual RCD board, one fault knocks out half the house. With a full RCBO board, only the faulty circuit trips. The 18th Edition Wiring Regulations effectively require RCBO-level protection on most circuits, and we only fit full RCBO boards.
Why does my RCBO keep tripping?
Common causes include: a faulty appliance leaking current to earth, water in an outdoor socket, a damaged cable, a failing immersion heater element, or moisture in a light fitting. We can pinpoint the cause in a single visit using insulation resistance testing.
How much does it cost to replace a fuse board with RCBOs?
A full RCBO consumer unit upgrade in Devon starts from £650 plus VAT for a standard domestic property, including the new unit, all RCBOs, certification and notification. We never quote dual RCD boards as a cheaper option — they are inferior protection.