Consumer Unit Upgrade Cost UK 2026 — Prices & What to Expect

A consumer unit (fuse board) replacement in the UK costs £400-800 including EICR inspection. Required when adding circuits, upgrading to RCD protection, or replacing old rewireable fuse boards. Metal consumer units with full RCD protection are now mandatory for new installations.

When You Need a Consumer Unit Upgrade

Mandatory upgrade situations: Your existing board has rewireable fuses (ceramic holders with wire fuse elements) — these offer no RCD protection and are a fire/shock risk. You're adding a new circuit (EV charger, cooker, shower, extension). An EICR identifies the consumer unit as C1 (dangerous) or C2 (potentially dangerous). You're selling a property and the buyer's survey flags the electrics. Recommended upgrade: Your board is plastic (fire risk — metal is now required). You have limited or no RCD protection. You're experiencing nuisance tripping due to an overloaded RCD. You want to add SPD (Surge Protection Device) for protection against voltage spikes. Signs your consumer unit is outdated: Rewireable fuses (wire elements you replace manually). Cartridge fuses (better than rewireable but no RCD). Original 1970s-1990s plastic board. No test button for RCDs (means no RCD protection). Faded labels or illegible circuit identification. Only a handful of circuits (modern homes typically need 8-12+).

Cost Breakdown: What You'll Pay

Basic consumer unit replacement (like-for-like): £400-600. Includes: new metal enclosure, main switch (100A), dual RCD split-load board, MCBs for each circuit, SPD, labelling, testing, and Part P compliance certificate. Full upgrade with EICR: £600-900. Adds a comprehensive EICR inspection and test of all existing circuits. Any C1/C2 issues found must be remedied (additional cost). RCBO board upgrade: £600-1,000. Each circuit gets its own RCBO (combined RCD + MCB). If one circuit trips, only that circuit is affected — not half the house. Premium option but worth it for convenience. Additional costs: Remedial work for EICR defects: £100-500 depending on findings. Additional circuits (EV charger, cooker): £100-200 per circuit. Earthing upgrades (if the earth is inadequate): £150-350. What affects the price: Number of circuits (more ways = higher cost). RCBO vs split-load (RCBOs cost £15-25 each vs £5-8 for MCBs). Remedial work needed. Geographic location (London/SE: 20-30% premium).

Split-Load vs RCBO: Which Board to Choose

Split-load (dual RCD): Two RCDs divide circuits into two groups. Cheaper to install. If one RCD trips, all circuits in that group lose power. This can be inconvenient — e.g., your fridge and freezer may lose power when an unrelated circuit trips. For most homes, this is adequate and cost-effective. RCBO board: Each circuit has its own RCBO providing individual RCD + overcurrent protection. If a fault occurs on one circuit, ONLY that circuit trips. More expensive (£100-200 premium) but far more convenient. Recommended for: homes with medical equipment, home offices, and anyone who values reliability. High integrity board: A split-load with selected critical circuits on RCBOs (fridge/freezer, alarm, server/NAS) and the rest on standard MCBs under the RCDs. Balances cost and convenience. Recommendation: If budget allows, choose an RCBO board. The £100-200 premium pays for itself in convenience over the board's 20-30 year lifespan.

The Upgrade Process: What to Expect

Before the work: Your electrician visits to assess the existing installation and provide a quote. They'll check: number of circuits, condition of wiring, earthing arrangement, and any issues visible at the current board. Day of work: Power off for 4-8 hours (depending on complexity). Old consumer unit removed. New metal board installed with main switch, RCDs/RCBOs, MCBs, and SPD. All circuits reconnected and labelled. Full testing of every circuit (insulation resistance, earth fault loop impedance, RCD trip time, polarity). Commissioning and handover. Duration: Simple replacement (same number of circuits): 4-6 hours. Complex (adding circuits, remedial work): 6-10 hours. After the work: Your electrician provides: Electrical Installation Certificate (EIC), schedule of test results, and Part P Building Regulations Compliance Certificate (sent to your local building control). Keep these documents — they're needed for selling the property and may be requested by insurers. Tips for the day: Charge devices beforehand. Prepare a cool box for fridge/freezer items. Plan to be home but not underfoot. Ask about progress and expected completion time.

DIY Safety: What You Must Not Do

Consumer unit replacement is NOTIFIABLE WORK under Part P. It must be done by a Competent Person registered with NICEIC, NAPIT, ELECSA, or Stroma. Penalties for DIY consumer unit work: Invalid home insurance if an electrical incident occurs. Difficulty selling your property without a compliance certificate. Potential prosecution by building control. Never attempt to: Replace your own consumer unit. Add new MCBs or circuits. Modify the metering or supply cable. Work on anything inside the consumer unit. What you CAN do: Identify your circuits by testing which MCB controls which area. Reset a tripped MCB or RCD (turn off, then back on). Test your RCDs quarterly (press the test button — it should trip immediately). Keep your circuit labels updated and legible. Check for signs of overheating (discoloration, burning smell). If you smell burning or see scorch marks on your consumer unit, isolate the main switch immediately and call an emergency electrician. This is a potential fire hazard.