Domakihub How to Upgrade Your Fuse Box to RCBOs (and When to Call a Pro)
Understand what the job involves, what to prepare, and why only a certified electrician should do the live work.
Reviewed by Domakihub home & decor pros · 2026-06-23 · 5 min read
Replacing an old fuse board with a modern RCBO consumer unit is one of the highest-impact safety upgrades you can make to a home, holiday rental, or hotel property. The video above walks through a real consumer unit swap, showing every stage from isolation to final testing — watch it for a clear picture of what the job looks like in practice. This guide explains the key concepts, what happens at each stage, and exactly what you need to do before a licensed electrician arrives so the work goes smoothly and your property meets current standards.
What Is an RCBO and Why Does It Matter?
An RCBO (Residual Current Breaker with Overcurrent protection) combines two safety devices in one unit: it trips on overloads and short-circuits like a standard MCB, and it also cuts power within milliseconds if it detects a fault current leaking to earth — the kind of fault that can electrocute a person or start a fire. Older consumer units typically have a single shared RCD protecting multiple circuits; if that RCD trips, everything on it goes dark at once.
With individual RCBOs, each circuit gets its own independent protection. A fault on the washing machine circuit trips only that breaker — the lights, fridge, and router stay live. For holiday rentals and hotel units in Greece, where you have guests who cannot troubleshoot a dark fuse board at midnight, this reliability difference is material.
Greek Electrical Standards and Who May Do the Work
In Greece, mains electrical work — including replacing a consumer unit or distribution board — must be carried out by a licensed electrician (ηλεκτρολόγος με άδεια ΔΕΗ/ΥΠΕΝ). On completion the electrician issues a Υπεύθυνη Δήλωση Εγκαταστάτη (UDE), the declaration of conformity that your insurer and any future buyer will require. Attempting this work yourself, or using an unlicensed person, voids building insurance and creates personal liability.
Greek installations vary significantly by era: properties built before 1990 commonly have ceramic fuse wire boards, properties from the 1990s–2010s often have basic MCB panels without any RCD, and modern builds follow ELOT HD 384 (the Greek equivalent of IEC 60364). Your electrician will assess which standard your wiring meets before specifying the new board.
What you can legitimately do yourself is prepare the site, gather information, and ensure access — all of which saves time (and therefore cost) on the day.
What Happens During an RCBO Consumer Unit Upgrade
- 1
Isolate the supply and safely remove the old board
The electrician contacts DEI (or your DSO) to confirm the supply can be safely isolated at the meter tails. The old consumer unit — whether ceramic fuse wire, MCB-only, or a basic split-load board — is de-energised, all circuits are disconnected at the board, and the enclosure is removed. Depending on the age of the installation, this stage may reveal wiring that needs remedial work before the new board is connected.
- 2
Inspect and test all existing circuits
Before any new hardware goes in, each circuit is tested: insulation resistance, continuity of protective conductors, and polarity. This is not optional paperwork — it establishes whether the existing wiring is safe enough to re-energise under a new board. Circuits that fail (typically old rubber-insulated cables or aluminium wiring) must be repaired or replaced. Your electrician will share the test results with you.
- 3
Mount the new RCBO consumer unit and label all ways
The new enclosure — ideally a metal-clad Type A RCBO board with surge protection device (SPD) to meet current best practice — is fixed to the wall in the same position or a better-accessible location. Each RCBO is sized and rated to match its circuit: 6 A for lighting, 16–20 A for socket rings, 32 A for cookers or EV chargers, and so on. Circuits are labelled clearly at this stage; accurate labelling protects future occupants and maintenance workers.
- 4
Connect all circuits, dress the cables, and reinstate supply
Each circuit cable is reconnected to its dedicated RCBO — line to the breaker, neutral to the neutral bar, earth to the earth bar. The meter tails are reconnected last. A professional will torque all terminals to manufacturer specification (a legally required step under the 18th Edition / HD 384) and dress cables neatly to prevent mechanical damage. The main switch is energised and each RCBO is switched on in sequence.
- 5
Commission, test, and issue the UDE declaration
With the board live, the electrician carries out full commissioning: RCD/RCBO trip-time tests (must trip within 40 ms at 5×IΔn), loop impedance measurements, and a functional check of every circuit. Any anomalies are corrected. Finally, a Υπεύθυνη Δήλωση Εγκαταστάτη is issued and signed — keep this with your property documents. For rental properties, share a copy with your property manager and insurer.
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FAQ
- How long does an RCBO consumer unit upgrade take?
- For a typical Greek apartment or villa with 6–12 circuits, expect 4–8 hours for a straightforward swap where all existing wiring passes testing. Older properties with rubber-insulated cables or aluminium wiring will take longer if remedial work is needed; a good electrician will flag this after the initial inspection so you can decide before work begins.
- Can I just replace individual MCBs with RCBOs without changing the whole board?
- Sometimes yes — if your existing consumer unit has a busbar design that accepts RCBO modules of the same manufacturer and rating series, an electrician can swap in RCBOs one circuit at a time. This is cheaper and less disruptive. However, it is not always possible (some older boards use proprietary formats that no longer have RCBO equivalents), and it does not add surge protection or upgrade the enclosure. Ask your electrician to quote both options.
- Is this upgrade required for Greek property insurance or short-term rentals?
- Greek insurers increasingly require a current UDE declaration (usually issued within the last 15 years) as a condition of buildings cover, and short-term rental platforms operating under Greek law (Airbnb hosts registered under the AADE short-term rental framework) are expected to maintain safe electrical installations. An RCBO upgrade is the surest way to produce a clean, up-to-date declaration. Some municipalities and fire-safety inspectors also check for functioning RCD/RCBO protection in rental properties.