EICR Failed? Consumer Unit Upgrade Guide for Cardiff Landlords

Consumer unit upgrades are the most common remedial action arising from EICR inspections of Cardiff rental properties. If your EICR has come back with a C2 observation flagging the consumer unit, here is exactly what it means, what needs to happen, and how to manage the process as a landlord.

Why Consumer Units Fail EICR Checks

Consumer units (fuse boxes) fail EICR checks for several common reasons. The most frequent is the absence of RCD (Residual Current Device) protection. An RCD cuts power within milliseconds if it detects current leaking to earth — the mechanism that causes electric shocks. Under current standards, all socket circuits, bathroom circuits, and outdoor circuits must be RCD-protected. Old consumer units — particularly those installed before 2008 — often have no RCD protection at all, or have a single RCD covering all circuits (which causes nuisance tripping).

The second most common failure reason is a plastic enclosure. Since 2016, all consumer unit enclosures must be of non-combustible (metal) construction under BS 7671 Regulation 421.1.201. Plastic units can allow internal arcing faults to develop into fires. Even if a plastic unit passes RCD testing, the plastic enclosure alone may attract a C2 or C3 observation that your insurance company or letting agent may require you to address.

The Remedial Process: Step by Step

Step 1: Receive and Review the EICR

Your EICR will specify the exact deficiency — for example, 'Consumer unit has no RCD protection on socket circuits. Code C2.' Review the full report carefully. Often there are additional C2 or C3 items that can be addressed at the same time as the consumer unit upgrade, saving you a second call-out charge.

Step 2: Obtain a Fixed-Price Quote

Contact a NICEIC Approved Contractor for a fixed-price consumer unit upgrade quote. The price should include: removal of the old unit, supply and installation of a new metal-clad consumer unit with RCD or RCBO protection, labelling of all circuits, full testing of the new installation, and an Electrical Installation Certificate (EIC). For most Cardiff 2–4 bedroom rentals, this should cost £450–£850.

Step 3: Inform Your Tenant

A consumer unit upgrade requires the property's power to be off for several hours. Give your tenant at least 48 hours' notice (ideally more). Arrange a date that works around their schedule — morning starts allow power to be restored by early afternoon in most cases. If the property is vacant, this is not a concern.

Step 4: The Upgrade

Most consumer unit upgrades in Cardiff rental properties complete within one working day. The old unit is safely removed, the new unit is installed and connected, all circuits are labelled, and the entire installation is tested. You receive an Electrical Installation Certificate on completion.

Step 5: Updated EICR

After the upgrade, if your original EICR had other C2 items that were also addressed, you may need an updated EICR to confirm the installation is now satisfactory. A reputable contractor will include this in their service or advise you clearly whether it is needed. The updated certificate is what you must provide to your tenant and retain for your records.

RCBO vs RCD: Which Should Your Cardiff Rental Have?

When upgrading, you have a choice between two types of consumer unit. A split-load board has two RCDs — each covering half the circuits. This is less expensive but means a single fault (like a faulty washing machine) trips all the circuits on that RCD, including your tenant's bedroom lighting. An RCBO board gives every circuit its own combined MCB and RCD. Only the faulty circuit trips. This is more expensive (typically £100–£150 more) but eliminates the most common tenant complaint — the entire property losing power because of a single fault.

For rental properties, we strongly recommend RCBO boards. The extra cost is minimal and the reduction in tenant complaints and emergency call-outs pays for itself rapidly.

Typical Costs for Cardiff Landlords in 2025

• 2-bedroom Cardiff terrace (split-load RCD board): £450–£550
• 2-bedroom Cardiff terrace (RCBO board): £550–£680
• 3-bedroom Cardiff semi (split-load RCD board): £500–£620
• 3-bedroom Cardiff semi (RCBO board): £620–£750
• 4-bedroom Cardiff HMO (RCBO board + additional circuits): £750–£950
• Consumer unit upgrade plus smoke alarm installation: add £200–£350

The 28-Day Deadline

Under the Renting Homes (Wales) Act 2016, C2 remedial work must be completed within 28 days of the EICR. Plan your upgrade booking immediately on receiving the report. With typical scheduling, you have approximately 14 days to book and complete the work and still have a comfortable buffer before the deadline. Waiting until day 20 to book will cause unnecessary stress and may push you past the legal deadline.