7 common reasons homes fail an EICR inspection

Helpful video reference. We use Artisan Electrics' body-cam walkthrough "7 Reasons Why Your Home Might Fail an EICR Inspection!" as the video reference here. Artisan Electrics is a Cambridge-based electrical company with over 369,000 subscribers, and their EICR content is consistently accurate on the UK regulatory requirements. The body camera footage makes it easy to see the actual faults as they are found on a real property.

1. Missing RCD protection on socket circuits

The 17th Edition of BS 7671, which came into force in 2008, made RCD protection mandatory for all socket circuits where a portable appliance might be plugged in outdoors or used in a bathroom. Many homes wired before that date have no RCD at all, or only a partial split-load board that leaves some circuits unprotected.

An inspector will test every socket to confirm it sits behind a 30mA RCD. If it does not, that is a C2 code at minimum. In some cases, where the socket circuit can supply a garden or garage with no earth path for fault current, the inspector may escalate to C1.

The fix is usually to add RCD sockets to unprotected circuits, or to upgrade the consumer unit so every circuit has individual RCBO protection.

2. No bonding to gas and water services

Main protective bonding conductors run from the earth bar in the consumer unit to the incoming gas meter and the incoming water pipe. Their job is to keep all metalwork in the property at the same potential so a fault cannot create a voltage difference between, say, a gas cooker and a tap.

Inspectors check these conductors are present, correctly sized (typically 10mm² for a TN-C-S supply), properly labelled at both ends and in good condition. Missing bonding, particularly to the gas service, is one of the most common C2 codes found in UK domestic properties.

Fitting the bonding conductors is straightforward work for an electrician. The difficult part is locating where the pipes enter the building and running the cable neatly back to the board.

3. Old or deteriorated cable insulation

Rubber-insulated wiring from the 1950s and 1960s dries out and becomes brittle over time. The outer sheath cracks, and the conductor insulation crumbles when flexed. Cloth-covered wiring from earlier decades is in an even worse state in most properties.

PVC cable from the 1970s is generally in better condition, but even this can harden after decades inside a warm ceiling void. An inspector who spots any rubber or cloth sheathing will normally record it as a C2 and may recommend full rewiring if the problem is widespread.

If a test reveals low insulation resistance between conductors or between conductors and earth, that indicates deteriorated insulation even where the cable looks intact from the outside.

4. Oversized or incorrect protective devices

A fuse or breaker is rated for the cable it protects, not for the appliance at the end of the circuit. A 30A rewireable fuse protecting a 1mm² lighting circuit is genuinely dangerous: if a fault develops, the cable will overheat and potentially catch fire long before the fuse blows.

Rewireable fuse boxes are particularly prone to this problem because cartridges are easy to replace with the wrong rating. An inspector will note the cable size and check that the protective device matches the current-carrying capacity of the smallest cable on that circuit.

Common mismatches: 30A fuses on lighting circuits (should be 5A or 6A), 30A on ring mains where the sockets cannot handle that load, and 20A or 32A MCBs on radial circuits wired in 1.5mm² cable.

5. Missing circuit protective conductors (earths)

Some older properties were wired in two-core cable with no earth conductor. Metal switches, sockets and light fittings were left unearthed, which is acceptable in some older standards but not in modern ones. Where the property now has metallic accessories, the absence of an earth presents a genuine shock risk.

An inspector will carry out a continuity test on the circuit protective conductor (CPC) for every circuit. A high reading, or an open circuit, is a C2. A missing earth on a metal back-box or a metal fitting is treated as more serious.

6. Mixed wiring colours without identification

Before 2004, UK wiring used red for line, black for neutral and green for earth. Since then, brown, blue and green-and-yellow are the standard. Many properties have both systems, particularly if extensions or alterations have been made over the years.

Mixed colours at a junction box or accessory are not necessarily dangerous, but they must be labelled to show which conductor is which. An inspector who finds unlabelled mixed cables cannot confirm polarity without testing, and will record an FI (further investigation) code until it is resolved.

The fix is to label every mixed connection with a bi-colour sleeve or a bridging marker and to record the circuit colours on the consumer unit schedule.

7. No adequate means of isolation at fixed appliances

Every fixed appliance must have a local means of isolation: a double-pole switch within sight of the equipment and accessible without crossing a hazard. An MCB in a consumer unit on a different floor does not count.

Common failures on this point: immersion heaters without a double-pole switch nearby, electric showers where the pull-cord switch is missing or has a failed mechanism, and cookers connected directly to wiring without a cooker connection unit.

Fitting an isolator is relatively simple work but must be done on an isolated circuit. An electrician will confirm the new switch is rated for the load and positioned in line with BS 7671 requirements.

When to call us

If you have received an unsatisfactory EICR report on a property in east Kent and you want an honest assessment of the remedial work needed, call Richard. We quote remedials at the same time as the EICR whenever possible, so you know the full cost before committing to anything.