A consumer unit (also called a fuse box or fuse board) is the main electrical distribution panel in a property that controls and distributes electricity to all circuits. Consumer units should be replaced when they contain rewirable fuses or lack RCD protection, when they show signs of damage or overheating, or when an EICR identifies them as non-compliant — which is common in properties with units installed before the 18th Edition of the IET Wiring Regulations.
At Manchester Compliance, we replace consumer units across Greater Manchester every week. In this article, we explain exactly what a consumer unit does, when it needs replacing, how much it costs, and what happens during the installation process.
What Is a Consumer Unit?
A consumer unit is the electrical hub of every home and commercial property. It sits between the electricity meter and the rest of the building’s wiring, and its job is to distribute power safely to every circuit ‚Äî lighting, sockets, cooker, shower, and everything else.
Inside a modern consumer unit, you will typically find:
- A main switch — this isolates the entire electrical supply to the property
- MCBs (Miniature Circuit Breakers) — these protect individual circuits from overload and short circuits by tripping automatically
- RCDs (Residual Current Devices) — these detect earth faults and disconnect the supply within milliseconds, protecting against electric shock and reducing the risk of electrical fires
- RCBOs (Residual Current Breaker with Overcurrent protection) — these combine the functions of an MCB and an RCD in a single device, offering the highest level of individual circuit protection
The consumer unit essentially replaced the old-style fuse box. While older fuse boxes used rewirable fuses or cartridge fuses, modern consumer units use MCBs and RCDs that provide far better protection. Additionally, since the 17th Edition of the IET Wiring Regulations (BS 7671), all new consumer units must be made from a non-combustible material — typically metal — rather than the old plastic enclosures.
Signs Your Consumer Unit Needs Replacing
So how do you know when your consumer unit needs replacing? Here are the most common warning signs we encounter during our work across Manchester:
- Rewirable fuses — if your consumer unit still uses wire fuses that you replace manually, it is outdated and does not meet current safety standards
- No RCD protection — RCDs save lives by detecting earth faults. If your board has no RCD protection, you are at significantly higher risk of electric shock
- Burning smell or scorch marks — these indicate overheating connections, which can lead to electrical fires. This requires urgent attention
- Frequent tripping — while occasional tripping is normal, regular or nuisance tripping often points to a fault on the board or overloaded circuits
- Wooden back board — older installations sometimes have the consumer unit mounted on a wooden board, which is a fire risk
- Plastic enclosure — consumer units manufactured before January 2016 may have plastic enclosures that do not meet the non-combustible material requirement introduced in Amendment 3 of the 17th Edition
- Failed EICR — if an Electrical Installation Condition Report identifies C1 (danger present) or C2 (potentially dangerous) observations related to the consumer unit, replacement is almost always the recommended course of action
If any of these apply to your property, we strongly recommend getting a professional assessment. In many cases, replacing the consumer unit is the single most impactful upgrade you can make to your electrical safety.
What Is the Difference Between a Fuse Box and a Consumer Unit?
Many people use the terms “fuse box” and “consumer unit” interchangeably, but there is an important technical difference.
An old-style fuse box contains rewirable fuses or cartridge fuses. When a circuit overloads, the fuse wire melts and breaks the circuit. However, rewirable fuses have no earth fault protection, and they rely on someone replacing the fuse wire with the correct rating — which does not always happen. As a result, they provide a much lower level of protection than modern alternatives.
A modern consumer unit uses MCBs instead of fuses. MCBs trip automatically and can simply be reset — there is no wire to replace. More importantly, modern consumer units include RCD protection, which detects earth leakage currents as small as 30mA and disconnects the supply in under 40 milliseconds. This is the level of protection that saves lives.
There are also different configurations of modern consumer units:
- Dual RCD board — the most common setup, where circuits are split across two RCDs. This is cost-effective but means that when one RCD trips, it disconnects multiple circuits at once
- RCBO board (also called a fully loaded board) — every circuit has its own individual RCBO, so a fault on one circuit only trips that circuit. This is the premium option and provides the best level of discrimination
- High integrity board — a hybrid approach with RCDs for most circuits and RCBOs for critical circuits like freezers and alarms
At Manchester Compliance, we fit all three types depending on the client’s requirements and budget. We always recommend the RCBO board where possible because it provides the best protection and the least disruption when a fault occurs.
How Much Does a Consumer Unit Replacement Cost?
A typical consumer unit replacement from Manchester Compliance costs from £500 + VAT. This includes the supply and installation of a new metal consumer unit with MCBs and RCD or RCBO protection, full testing of every circuit, and a Part P Electrical Installation Certificate (EIC).
The exact cost depends on several factors:
- Number of circuits — a larger property with more circuits requires a bigger board and more MCBs or RCBOs
- Board type — a dual RCD board is less expensive than a fully loaded RCBO board
- Remedial work — if existing wiring faults are discovered during testing, these will need to be addressed before the new board can be signed off
- Earthing and bonding — older properties may need their main earthing and bonding upgraded to meet current regulations, which adds to the cost
We always provide a fixed quote before starting any work, so there are no surprises. Furthermore, because we carry out EICRs and rewires alongside consumer unit upgrades, we can often bundle services together for better value — particularly for landlords with multiple properties.
Is a Consumer Unit Replacement Notifiable Work?
Yes. Replacing a consumer unit is notifiable work under Part P of the Building Regulations (England and Wales). This means it must either be carried out by a registered competent person — such as an NICEIC Approved Contractor — or the homeowner must apply for building control approval from the local authority before the work starts.
As an NICEIC Approved Contractor, Manchester Compliance is authorised to self-certify consumer unit replacements. This means we handle the entire notification process on your behalf, and you receive an Electrical Installation Certificate that confirms the work complies with BS 7671 and the Building Regulations.
Importantly, if someone who is not Part P registered replaces your consumer unit without notifying building control, the work is technically illegal. This can cause serious problems when you come to sell the property, because your solicitor will need evidence that the electrical work was carried out lawfully. Therefore, always use a registered electrician for this type of work.
What Happens During a Consumer Unit Replacement?
A consumer unit replacement typically takes between 4 and 8 hours depending on the size and complexity of the installation. Here is what happens step by step:
- Isolate the supply — the engineer turns off the electricity at the main switch and confirms the supply is dead using a voltage tester
- Remove the old board — all circuits are carefully disconnected and labelled, and the old consumer unit is removed
- Install the new consumer unit — the new metal consumer unit is mounted, and all circuits are reconnected to the correct MCBs, RCDs, or RCBOs
- Upgrade earthing and bonding — if the existing earthing or bonding does not meet current requirements, it is upgraded at this stage
- Test every circuit — the engineer carries out a full schedule of tests on every circuit, including insulation resistance, earth fault loop impedance, polarity, and RCD trip times
- Issue an Electrical Installation Certificate (EIC) — this certificate confirms the installation complies with BS 7671 and the Building Regulations, and it is submitted to the NICEIC for Part P notification
Throughout the process, the electricity will be off for most of the day. We always let you know in advance so you can plan accordingly. Once the new board is energised and tested, everything should work exactly as before — just much safer.
During testing, our engineers may also identify other issues in the installation, such as non-fire-rated downlights or deteriorated wiring. If remedial work is needed, we will explain exactly what we have found and provide a clear quote before proceeding.
Consumer Unit Replacements from Manchester Compliance
At Manchester Compliance, we replace consumer units for homeowners, landlords, letting agents, and property managers across Greater Manchester. Whether it is a single domestic property or a portfolio of rental homes, we deliver the same standard of work every time.
Here is why clients choose us for their consumer unit upgrades:
NICEIC Approved Contractor
Part P Registered
Full certification included
Fast turnaround for landlords
Competitive Manchester pricing
EICR + remedial work packages available
For landlords in particular, we offer a streamlined service. If an EICR flags the consumer unit as unsatisfactory, we can quote and schedule the replacement immediately — often within the same week. This helps landlords meet their legal obligations under the Electrical Safety Standards in the Private Rented Sector (England) Regulations 2020 without delays.
We also frequently carry out consumer unit replacements as part of a full house rewire. When we rewire a property, the consumer unit is always replaced as standard, giving the property a completely new electrical installation from the meter to the final circuits.
We serve Manchester, Salford, Stockport, Trafford, Bolton, Bury, Oldham, Rochdale, Tameside, Wigan, and surrounding areas.
Need a Consumer Unit Replacement in Manchester?
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Published March 2026 by Manchester Compliance Ltd — NICEIC Approved Contractor serving Greater Manchester, Cheshire, and the North West.