Consumer unit replacement costs explained

What should a consumer unit replacement include?

A proper quotation should describe the proposed board, how each circuit will be protected and whether surge protection is included. Modern designs often use individual RCBOs so a fault on one circuit is less likely to disconnect unrelated parts of the property.

Before replacement, the installation needs sufficient assessment to identify obvious problems. After installation, every connected circuit must be tested and the results recorded. The new board should be clearly labelled, and the appropriate electrical certificate and Building Regulations notification should follow.

• Initial survey of the existing board, supply, earthing and bonding.
• Safe isolation and removal of the old fuse box or consumer unit.
• A suitable non-combustible enclosure and correctly rated devices.
• RCBO, RCD and surge-protection arrangements stated in the quotation.
• Circuit identification, testing, schedules and durable labelling.
• Electrical Installation Certificate and notification where required.

Why does the existing wiring affect the price?

A new consumer unit does not renew the cables connected to it. If a circuit has low insulation resistance, a shared neutral, damaged accessories or unsuitable alterations, the defect may need to be found and repaired before that circuit can be safely energised on the new protection.

Older installations may also have short conductors, mixed circuit wiring or missing identification. Some issues are visible during the survey; others only become clear during testing. The quotation should explain how unforeseen faults will be handled and whether a pre-change test is included.

• Deteriorated cable insulation or damage hidden behind accessories.
• Neutral conductors shared between circuits that should be separate.
• Incomplete earthing or bonding arrangements.
• Overloaded circuits and incorrectly selected protective devices.
• Solar PV, EV chargers, outbuildings or other supplies needing coordination.
• Circuits that cannot be identified or safely isolated.

RCBOs, RCDs and surge protection

An RCD monitors current flowing out and back and disconnects when it detects an imbalance. In a split-load board, one RCD may protect several circuits. An RCBO combines overcurrent and residual-current protection for an individual circuit, which improves separation and can make future fault finding easier.

Surge protective devices help limit transient overvoltage that could damage sensitive equipment. The need and design should be considered as part of the installation rather than treated as a decorative add-on. Ask the electrician to explain the selected arrangement and any limitations.

What makes one quotation more expensive than another?

Product quality, circuit count and the protective design all affect the material cost. Labour varies with the condition of the existing installation, the space around the board and the time needed to identify, extend and test conductors.

Check whether testing, certification, notification, labels and small remedial items are included. A lower figure may be based on fewer protective devices, exclude fault finding or assume that every existing circuit will pass testing without work.

A realistic consumer unit budget

Published UK cost guidance from late 2025 gives an average consumer unit replacement range of about £450 to £750 including VAT. Current Chelmsford quotations can sit below or above that range depending on the circuit count, chosen RCBO arrangement, surge protection, board location and condition of the wiring.

Use the range for initial planning only. A larger board, difficult meter position, conductor extensions, earthing work or faults found during testing can increase the total. The written quotation should state what happens if an existing circuit cannot be safely reconnected.

Questions to ask before accepting the quotation

Ask what protective device each circuit will have, what happens if a circuit fails testing and which documents you will receive. If the board is in a cupboard or a recently decorated area, also agree how access, dust protection and making good will be managed.

• Will each circuit have individual RCBO protection?
• Is surge protection included and how has the decision been made?
• Are earthing and bonding checks included?
• Is pre-change testing allowed for?
• How are unforeseen circuit faults priced and authorised?
• Will I receive the certificate and Building Regulations notification?