Consumer Unit Replacement Cost UK: Pricing Guide 2024

Quick Answer: A UK consumer unit replacement prices at £450-£750 for a like-for-like dual-RCD board, £550-£950 for an RCBO board with surge protection, and £750-£1,400 for a metal-clad RCBO board with AFDD protection and supply upgrade. The work is notifiable under Building Regulations Part P and must be certified by a competent person (NICEIC, NAPIT, ELECSA registered electrician). Allow a single day for the swap; cable testing and certification typically add 1-2 hours.

Summary

Consumer unit replacement is the most-quoted standalone domestic electrical job in the UK. It is also one of the most variable in pricing — quotes for the same job can range £400-£1,500 depending on board spec, supply upgrades needed, and certification approach. The customer often sees the quote variability as price-gouging; in reality it reflects genuine specification differences.

The board choice matters more than the labour rate. A dual-RCD board (the old standard) is £180-£280 supplied; an RCBO board (per-circuit protection) is £280-£480 supplied; an AFDD-protected board is £450-£850 supplied. The fitting time is similar (4-6 hours typically) — the spec change is the cost change. Always offer the customer a tier breakdown: budget, mid, premium.

The second cost variable is what's discovered during the change. A typical 1990s house may need new main earth bonding to gas and water (£80-£180), new tails and meter tails (£60-£150), and an EICR-style minor remedial works (£180-£450). Quoting these as separate provisional sums protects the trade against scope creep.

This guide covers all three tiers, the discoveries common in older properties, and the certification chain. For full rewires see full rewire pricing guide; for EICR work see eicr pricing guide; for EV charger circuits added during CU change see ev charger pricing guide.

Key Facts

Consumer unit costs (supplied)

Labour and ancillary costs

Regulatory

Quick Reference Table

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Spec Tier Board Type Property Type Labour Total Range (Regional) Total Range (London)
Budget Dual-RCD 12-way Flat / small terrace 0.5-1 day £450-£650 £550-£800
Budget Dual-RCD 18-way Semi / detached 0.75-1 day £550-£750 £700-£950
Mid RCBO 12-way Flat / terrace 0.75-1 day £650-£900 £800-£1,100
Mid RCBO 18-way + SPD Semi / detached 1-1.25 day £800-£1,150 £1,000-£1,400
Premium AFDD-protected RCBO High-fire-risk dwelling 1-1.5 day £1,100-£1,500 £1,400-£1,900
Premium RCBO + SPD + EV provision EV-ready installation 1.25-1.75 day £1,200-£1,800 £1,500-£2,200

Add £80-£180 for main earth bonding, £60-£150 for meter tails, £180-£600 for any remedial work discovered.

Detailed Guidance

Pre-survey — what to check before quoting

A consumer unit replacement quote without a pre-visit survey is risky. Required checks:

  1. Existing CU type and age — 1980s or older boards are likely to need full main earth bonding upgrade; 1990s boards may have non-compliant RCD coverage; 2000s boards may already be RCD-protected but split-load
  2. Main earth path — check earth electrode rod (for TT systems) or PME earth (TN-C-S systems). PME systems are more common in modern UK housing
  3. Bonding to gas and water — 10mm² or 16mm² minimum (depending on supply cable size); older houses may have 6mm² that no longer complies
  4. Meter tails — should be 16mm² double-insulated; older houses may have 10mm² single-insulated needing replacement
  5. Service head and DNO seals — DNO seal must be broken to replace meter tails; book DNO disconnect-reconnect appointment in advance for safety
  6. Existing circuit count — confirm board has enough ways for all existing + planned circuits (EV charger, solar PV, etc.)
  7. AFDD requirement — HMOs, high-rise dwellings, and care homes need AFDD per Reg 421.1.7

A proper survey is 30-45 minutes. It catches scope creep before the quote rather than during the install.

Board tier choice — Budget, Mid, Premium

The three-tier offer is the trade's friend. Customers respond better to "we offer three options" than to a single take-it-or-leave-it quote.

Budget tier — Dual-RCD board (£180-£350 board cost)

Two RCDs each protecting a bank of 6-8 circuits. Compliant with BS 7671 but a single RCD trip kills half the house (lighting on one RCD, sockets on the other typically). Suitable for budget rentals or short-stay properties.

Mid tier — RCBO board (£280-£650 board cost)

Each circuit on its own RCBO. Single circuit trips don't affect others. Recommended for all owner-occupier installations. Trip granularity makes fault-finding easier and improves quality-of-life when a single appliance trips.

Premium tier — AFDD-protected board (£450-£850 board cost)

Each circuit on its own AFDD + RCBO. AFDDs detect arc faults (loose connections, damaged cables) that cause fires but don't draw overcurrent or earth leakage. Required for HMOs and high-risk applications; recommended for owner-occupiers in older properties.

Always show the customer the boards. Most respond to seeing the unit on a phone photo or supplier catalogue — the metal-clad premium boards "look" the part and shift customers up the tier.

Surge protection (SPD)

Surge Protection Devices are required per BS 7671:2018+A2:2022 Reg 443 unless a risk assessment indicates otherwise. The risk assessment is the get-out for most domestic installations, but installing SPD is becoming standard practice for new boards.

Type 2 SPD is the standard domestic device. Connects to the main bus-bar at the consumer unit, diverts overvoltage transients (typically from lightning surges or DNO supply faults) to earth. Cost £80-£180 supplied + 30 minutes labour.

The case for SPD: modern households have £10,000+ of electronics (TVs, computers, kitchen appliances, smart home gear). A single surge can write off this stock. SPD insurance against this is cheap relative to the protected asset value. Always offer SPD as a line item.

Main earth bonding upgrades

The earth bonding from the consumer unit to the gas and water services is the most-commonly-found non-compliance in older properties. BS 7671 requires 10mm² minimum (sometimes 16mm² depending on the supply size) bonded to all extraneous-conductive-parts (gas pipe within 600mm of meter, water pipe within 600mm of stop tap, structural metalwork).

Pre-2008 properties typically have 6mm² bonding which no longer complies. Replacement is straightforward — 3-5m of 10mm² green/yellow earth cable plus two earth clamps. Labour 1-2 hours. Cost £80-£180. Always include this as a default in the quote, removable if the existing bonding is already 10mm²+.

Meter tails and service head

Meter tails are the cables between the supply meter and the consumer unit's main switch. They should be 16mm² double-insulated, separately sheathed. Older installations may have 10mm² single-insulated or even mixed-colour conductors (illegal under current regs).

Replacing meter tails requires breaking the DNO seal at the supply head — strictly this is a DNO operation, not a trade operation. Two approaches:

  1. Book DNO disconnect — DNO turns off supply, removes seal, electrician replaces tails, DNO returns to reconnect and reseal. £60-£200 DNO fee plus a half-day wasted waiting.
  2. Use a sealed isolator — install a Henley block isolator that allows the tails to be replaced without breaking the DNO seal. Faster but requires the Henley to be DNO-approved.

Modern best practice is to install a Henley block as standard with the CU change. Provides a service isolator and enables future work without DNO involvement.

Service supply upgrade (DNO work)

Older houses have 60A or 80A supply heads. Modern loads (electric showers, EV chargers, induction hobs, heat pumps) push these supplies to their limit. Upgrading to 100A is a DNO operation:

This is NOT in the electrician's scope unless they coordinate the DNO appointment. Always inform the customer if a supply upgrade is needed and provide the DNO contact details — but don't bundle the DNO fee into the trade quote.

Hidden costs and risk premium

The five most-missed cost lines in consumer unit replacement quotes are: (1) re-routing tails when the new CU is wider than the old one and won't fit the existing back-board; (2) discovery of asbestos cement back-boards in pre-2000 installations (specialist removal £80-£250); (3) supplementary equipotential bonding to bathrooms — required if MET (main earthing terminal) is more than 2m from the bathroom; (4) cable insulation testing — if existing circuits fail insulation resistance (IR test), they must be repaired or replaced; (5) certification paperwork time — EIC, schedule of tests, Building Regs Compliance Certificate (45-60 mins paperwork).

Risk premium of 15-25% is standard on pre-1985 properties: rubber-and-fabric cables, lead piping bonded to consumer unit chassis, undocumented sub-mains, TT earthing requiring earth rod testing.

Frequently Asked Questions

Is consumer unit replacement always notifiable?

Yes — full consumer unit replacement is always notifiable under Building Regulations Part P. Must be certified by a Part P competent person scheme member (NICEIC, NAPIT, ELECSA, BSI, etc.) or inspected by Local Authority Building Control. The EIC (Electrical Installation Certificate) and Building Regulations Compliance Certificate must be issued to the customer within 30 days.

Should I replace tails and bonding while changing the consumer unit?

Almost always yes. The cost of replacing tails and bonding during a CU change is 5-10% of the total job; doing them later as a separate visit doubles the labour. Best practice is to replace both as standard during any CU change, unless the existing tails and bonding are already compliant (post-2008 compliant 16mm² tails, 10mm²+ main bonding to gas/water).

Can I replace a CU on a TT-earthed system (no PME)?

Yes — TT systems (typically rural houses with earth rod, no PME) are fully supported. The new CU still uses standard 30mA RCD or RCBO protection but the main earth comes from the earth rod rather than the DNO supply. Always test the earth electrode resistance (should be ≤200Ω, ideally ≤100Ω) — older rods corrode and may need replacement. Earth rod test £40-£80; replacement £150-£280.

Do I need to do an EICR before or after the CU change?

Best practice is a "pre-rewire EICR" before any CU change to identify circuits that may fail testing. After the CU change, certify with an EIC for the new CU and any altered circuits, plus an EICR-style summary for existing circuits if any are non-compliant. Quoting the CU change without checking existing circuit condition risks committing to certifying circuits that fail testing.

How long does a consumer unit replacement take?

4-6 hours for a straightforward like-for-like swap. 6-8 hours if main earth bonding and meter tails are also being replaced. 8-10 hours if Henley block isolator is being added. The customer is without power for 2-4 hours typically during the change-over phase.

Regulations & Standards