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.