How to Price a Consumer Unit Replacement: Labour, Spec and Certification Costs

Quick Answer: A typical UK domestic consumer unit replacement prices £480–£950 fitted in 2026, comprising £180–£350 for an 18th Edition Amendment 2 compliant RCBO board with surge protection, £80–£180 for incoming tail replacement and Henley block, and £220–£420 in labour for 4–8 hours of work plus testing and certification. Metal-clad enclosures are mandatory under BS 7671 421.1.201; SPD Type 2 is now required by BS 7671:2018+A2:2022; AFDDs are recommended on socket circuits in single-family domestic and required in HMOs and care homes. The work is notifiable under Building Regulations Part P.

Summary

A consumer unit (CU) replacement is one of the most common pricing exchanges between an electrician and a homeowner — and one of the easiest to under-quote. The headline cost looks like a £180 board and a half-day's labour, but compliant work in 2026 includes surge protection, RCBO-per-circuit, possibly AFDDs, a thorough test of every existing circuit, a remedial allowance for the bits that fail those tests, and Building Regulations Part P notification. A clean quote shows each line.

The most common reason a CU is replaced is age — pre-2016 plastic boards, sub-fault on existing RCDs, or unidentified additions over the years that don't comply with current standards. Most replacements happen at the same time as another job (kitchen rewire, EV charger install, electric shower upgrade) where a CU swap is the easiest way to get the rest of the work signed off. Standalone CU replacements driven solely by an EICR C2 finding are less common but priced identically.

The 18th Edition Amendment 2 (effective 28 September 2022) brought two changes to CU spec: SPD Type 2 surge protection became a default requirement (subject to risk assessment), and AFDDs became mandatory in specific high-risk applications. Plastic CUs were already banned (since January 2016 for domestic use) — any replacement of a plastic board to plastic is non-compliant. Electricians replacing plastic CUs encounter customers who think £600 is a lot for a "just swap the box" job — the price reflects current spec, not 2010 spec.

Key Facts

Quick Reference Table

Spending too long on quotes? squote turns a 2-minute voice recording into a professional quote.

Try squote free →
CU spec / job type Board cost Total fitted 2026 Labour Notes
12-way RCBO board, basic 18th Edition AM2 spec £150–£220 £480–£780 4–6 hours Volume domestic spec
14–18 way RCBO + SPD, 3-bed semi £220–£320 £580–£950 5–7 hours Most common 2026 install
Larger 4-bed detached, 18-way + SPD £280–£400 £750–£1,250 6–9 hours More circuits, more terminations
HMO spec — full AFDD on socket circuits £400–£650 £950–£1,650 6–9 hours AFDDs add £45–£90/circuit
CU relocation (different position) £220–£320 £900–£1,650 8–14 hours Includes new tails routing
CU + meter tails upgrade (DNO co-ordinated) £280–£400 £850–£1,400 full day 25mm² tails, DNO seal removal
CU + EICR pre-work (older property) £220–£350 £750–£1,250 5–8 hours Includes pre-fit EICR test
Replace plastic CU to metal (compliance only) £180–£280 £580–£980 4–6 hours Direct swap, retain RCDs
Smart-home CU (Hager Smart, Schneider Wiser) £450–£750 £1,200–£1,950 7–10 hours Energy monitoring, app control

Detailed Guidance

What's actually in a 2026 compliant CU

A current-spec consumer unit for a typical 3-bed semi:

Component Spec Standard Trade buy
Metal-clad enclosure (12–18 way) Steel, IP2X minimum BS EN 61439-3 £80–£140
Main switch 100A DP or 4P for some installations BS EN 60947-3 £20–£35
RCBO Type A per circuit 30mA RCD + MCB combined BS EN 61009 £18–£32 each
Type 2 SPD Pluggable cartridge BS EN 61643-11 £80–£180
Henley block (cut-out side) Single phase 3-way or dual BS EN 61439 £15–£40
Tails 25mm² double-insulated 6181Y or equivalent BS 6004 £8–£12/m
Earth bar / MET extension Brass or copper £8–£15

For a 12-circuit board: enclosure £100, main switch £25, 12 × RCBO £25 = £300, SPD £140, tails £30, sundries £40. Total trade buy: £635 for the spec components. Plus £80–£180 in associated items (cable glands, ID labels, schedule documentation).

Why the price has gone up since 2020

Three drivers have pushed CU pricing up 30–50% since 2020:

  1. Amendment 2 to BS 7671 — SPDs required, more RCBO use over dual-RCD split-load
  2. Material inflation — copper and steel cost increases through 2022–2024
  3. Manufacturer consolidation — Hager, Schneider, Wylex and Crabtree raised list prices 12–25% over 2022–2025

Trade discount has compressed too. Pre-2020, a 35–45% trade discount on list was typical. By 2026, 25–35% is more common. The end customer sees both effects together.

Type 2 SPD — when can it be omitted?

BS 7671:2018+A2:2022 requires surge protection unless a risk assessment justifies its omission. The risk assessment formula in BS 7671 Annex 443 produces a number called CRL — if CRL <1000, SPD can be omitted; if CRL ≥1000, it's required.

In practical terms:

For most domestic CUs in 2026, including the SPD is the default. £80–£180 add to the bill but real protection of TVs, IT equipment, smart home devices, and modern appliances against transient overvoltage.

AFDD — when is it mandatory vs recommended?

The 2022 update to BS 7671 (421.1.7) lists where AFDDs are required:

In single-family domestic dwellings, AFDDs are recommended but not mandatory. Most UK domestic CUs in 2026 are still RCBO-only, no AFDD. Adding AFDDs to all socket circuits adds £200–£500 to the CU cost.

For HMOs and care homes, the AFDD line must appear in the quote — it's a regulatory requirement, not a sales upgrade.

Henley block, tails and DNO co-ordination

The CU side of a domestic install is the electrician's responsibility. The DNO (Distribution Network Operator — UKPN, Northern Powergrid, SP Energy Networks, etc.) controls everything upstream of the meter. Two zones meet at the Henley block:

If the existing tails are in good condition (25mm² double-insulated, less than 5m, no joints) they can stay. If they're old single-insulated cable, undersized (16mm² is no longer compliant for >60A supply), or showing thermal damage, they must be replaced. The Henley block is required to allow the electrician to disconnect the CU without breaking DNO seals.

DNO seal removal: in some cases (long tails, meter relocation, supply isolation needed) the DNO must attend. This adds £80–£200 in DNO fees and 1–4 hours of waiting time.

The pre-fit test that catches the problems

Before disconnecting an existing CU, the electrician runs a brief test to identify circuits that won't pass the post-fit test. Common findings:

Where pre-fit testing reveals problems, the quote needs a remedial allowance. £180–£500 is typical for a couple of small remedial fixes; a major remedial (e.g. borrowed neutral throughout the upstairs lighting) can be £400–£900 of additional rewiring.

A clean quote includes a "remedial works allowance" line — £150–£300 — to cover small fixes uncovered during the work. Anything bigger is priced separately as variation.

Programme — typical day on a CU swap

Single-day job for a competent electrician. Typical schedule:

Total: 7–8 hours = single day. Larger boards or relocations push to 1.5 days.

Part P notification and certification

A CU replacement is notifiable under Part P. The Competent Person Scheme (NICEIC, NAPIT, ELECSA, STROMA) handles notification automatically when the electrician submits the certificate. No separate Building Control fee.

Documentation issued to the customer:

Without scheme registration, the electrician must submit a Building Notice to the local council and pay LABC fees of £200–£550. Most domestic CU replacements are done through scheme-registered contractors.

Frequently Asked Questions

How much does a new fuse box cost in the UK 2026?

£480–£950 fitted for a typical 3-bed home. The headline term "fuse box" is dated — the modern equivalent is a metal consumer unit with RCBOs (combined RCD + MCB) protecting each circuit, plus a Type 2 surge protection device. Quotes that come in significantly under £450 are either skipping the SPD, using the cheapest possible board, or skipping the proper testing and certification.

Do I have to replace a plastic consumer unit?

Plastic CUs in domestic dwellings have been non-compliant since January 2016 (BS 7671 421.1.201). Existing plastic boards aren't illegal — but any modification or replacement triggers an upgrade to metal. If your CU is plastic and an electrician opens it for any reason (adding a circuit, fault-finding), you should expect the CU swap to come up in the conversation.

Can I replace the consumer unit myself?

No. Consumer unit replacement is notifiable under Building Regulations Part P. It must be done by a Competent Person Scheme registered electrician, or notified to Local Authority Building Control with appropriate fees. Self-installed work without notification is unlawful and creates problems at conveyancing.

What's the difference between an RCBO board and a dual-RCD board?

A dual-RCD board has two RCDs, each protecting a bank of circuits (typically 5–6 each). A fault on any one circuit trips the whole bank. An RCBO board has a separate RCBO (combined RCD + MCB) for each circuit, so a fault only trips the affected circuit. RCBO boards are now the default for new installations — better fault discrimination, less nuisance, slightly higher upfront cost.

Will my electrician need to turn the power off all day?

Power is off for 4–6 hours typically — long enough for the new board to be installed, terminated, and tested. If your supply has external isolators (some properties do), supply can be intermittent rather than off all day. Otherwise plan for half a day without power. Fridges and freezers usually survive a half-day power loss without issue.

Regulations & Standards