All EICR Failed Codes Explained: C1, C2, C3 and FI Faults in One Place

An EICR report can look simple at first. You receive the certificate, check whether it says satisfactory or unsatisfactory, then see a list of observations with codes such as C1, C2, C3 or FI.

The problem is that many landlords, homeowners, estate agents and property managers do not fully understand what those codes mean. One small line on an EICR report can decide whether your London property passes, fails, needs urgent electrical work, or requires further investigation before a satisfactory certificate can be issued.

This guide explains the main EICR failed codes in plain English, including what they mean, how serious they are, and what usually happens next.

If you already have a failed report and want to check a specific fault, use our dedicated EICR Code Cheatsheet. It has been created to help London landlords, homeowners and property professionals quickly understand common EICR observations without guessing what the technical wording means.

What Is an EICR?

An EICR, or Electrical Installation Condition Report, is a formal inspection of the fixed electrical installation inside a property. It checks whether the electrical system is safe for continued use.

This can include the condition of:

• Consumer units
• Fuse boards
• Sockets
• Lighting circuits
• Earthing and bonding
• RCD protection
• Wiring condition
• Circuit safety
• Distribution boards
• Fixed electrical accessories

For landlords in London, an EICR is especially important because rental properties must have a valid electrical safety report. If the report is unsatisfactory, the landlord normally needs to arrange remedial work before the property can be considered electrically compliant.

If you need a full inspection, you can book an EICR certificate in London with our team.

What Does a Failed EICR Mean?

A failed EICR means the electrical installation has one or more issues that prevent the report from being marked as satisfactory.

This does not always mean the whole property is dangerous. Sometimes the report fails because of one serious defect. Other times, several smaller issues combine to create a wider safety concern.

An EICR usually becomes unsatisfactory when it includes:

• C1 observations
• C2 observations
• FI observations, depending on the issue

A report with only C3 observations is normally still satisfactory, although improvements may be recommended.

If your EICR has failed, the next step is to understand which codes appear on the report and what they mean. You can also visit our failed EICR remedial work page if you already know repairs are required.

EICR Codes Explained

EICR observations are given classification codes. These codes tell you how serious the issue is and what type of action may be required.

The main EICR codes are:

• C1: Danger present
• C2: Potentially dangerous
• C3: Improvement recommended
• FI: Further investigation required

Each code has a different level of urgency. If you are trying to understand the wording on your report, our EICR Code Cheatsheet can help you search common observations and understand what they usually mean.

C1 EICR Code: Danger Present

A C1 code means there is immediate danger. This is the most serious type of EICR observation.

In simple terms, a C1 means someone could be at risk of electric shock, burns, fire or serious injury if the issue is not made safe immediately.

Common examples of C1 faults include:

• Exposed live parts
• Broken electrical accessories exposing conductors
• Severely damaged consumer unit parts
• Accessible live terminals
• Burnt or overheating electrical components
• Dangerous DIY electrical work
• Open junction boxes with live wiring exposed

A C1 fault usually needs immediate action. In many cases, the electrician may need to make the danger safe during the inspection before leaving the property.

Does a C1 Code Fail an EICR?

Yes. A C1 observation will normally make the EICR unsatisfactory.

If your report includes a C1, you should not delay. The issue needs urgent attention because the risk is immediate.

For urgent repair support, visit our EICR remedial work in London page.

C2 EICR Code: Potentially Dangerous

A C2 code means the installation is potentially dangerous. This does not always mean there is immediate danger at the exact moment of inspection, but it means a dangerous situation could occur under fault conditions.

C2 is one of the most common reasons an EICR fails.

Common C2 faults include:

• No RCD protection where required
• Missing main protective bonding
• Incorrect earthing arrangements
• Damaged sockets or switches
• Loose electrical connections
• Incorrectly installed circuits
• Poorly protected cables
• High earth fault loop impedance readings
• Undersized protective conductors
• Unsafe consumer unit conditions
• Bathroom electrical accessories with insufficient protection

Does a C2 Code Fail an EICR?

Yes. A C2 observation will normally make the report unsatisfactory.

This is where many landlords get caught out. They assume the property only needs work if something is visibly broken. But many C2 issues are hidden inside the electrical system and only appear after proper testing.

For example, a socket may work perfectly, but the circuit may still fail because it does not disconnect quickly enough under fault conditions.

If your property has a failed EICR because of C2 observations, our failed EICR remedial work service can help you understand what needs to be corrected.

C3 EICR Code: Improvement Recommended

A C3 code means the installation is not necessarily unsafe, but improvement is recommended.

A C3 is generally less serious than C1 or C2. It is often used where the installation does not meet the latest standard but is not considered dangerous enough to fail the report.

Common C3 observations include:

• Older electrical accessories still in usable condition
• Lack of modern labelling
• Minor consumer unit improvements
• Older wiring colours
• Absence of RCD protection in lower-risk situations
• Improvements that would bring the installation closer to current standards

Does a C3 Code Fail an EICR?

Usually, no.

A report with only C3 observations can often still be marked as satisfactory. However, ignoring C3 issues for years can lead to larger problems later, especially in older London properties.

A C3 is best treated as an early warning. It gives you a chance to improve the installation before the issue becomes more expensive or more serious.

If you are planning an inspection before renting or selling a property, see our EICR certificates for homeowners in London page.

FI EICR Code: Further Investigation Required

An FI code means the electrician could not confirm whether the installation is safe without further investigation.

This code is used when something needs more detailed checking.

Common FI situations include:

• Unusual test readings
• Hidden or inaccessible wiring
• Suspected borrowed neutrals
• Circuits that cannot be fully traced
• Intermittent faults
• Signs of overheating without a clear cause
• Unclear earthing or bonding arrangements
• Electrical alterations with no proper records

Does an FI Code Fail an EICR?

An FI code can make the report unsatisfactory because the electrician cannot confirm safety until further investigation is completed.

This is important. Some property owners assume FI means “not urgent”. That is not always correct. FI means the condition is uncertain, and uncertainty in electrical safety cannot be ignored.

If your EICR has an FI observation, the issue should be investigated properly before assuming the installation is safe. You can arrange this through our EICR testing in London service.

Common EICR Failed Codes Found in London Properties

London properties often have a mixture of old and modern electrical systems. It is common to find Victorian, Edwardian, post-war, 1970s, 1990s and modern installations all across the city.

Because of this, failed EICR reports in London often include similar patterns.

Below are some of the most common EICR failures.

No RCD Protection

RCD protection is one of the most common issues found during an EICR.

An RCD is designed to disconnect power quickly if it detects a fault. It helps reduce the risk of electric shock.

No RCD protection may be coded as C2 in many situations, especially where sockets, bathrooms, outdoor circuits or concealed cables are involved.

This is common in older London flats, rental properties and houses with old fuse boards.

If your property has not been tested recently, book an EICR test in London to check whether the installation is still safe.

Missing Main Protective Bonding

Main protective bonding connects services such as gas and water pipework to the electrical earthing system. If bonding is missing or incorrect, the risk of electric shock can increase under fault conditions.

This is a common failed EICR issue in:

• Rental flats
• Converted houses
• Older maisonettes
• Properties with old pipework
• Properties that have had partial refurbishments

Missing bonding is often coded as C2.

For landlords, this should be treated seriously because it can prevent a property from receiving a satisfactory report. See our EICR certificates for landlords in London page for landlord-specific guidance.

High Ze or High Earth Fault Loop Impedance

High Ze or high impedance readings mean the electrical system may not disconnect quickly enough if a fault occurs.

This is technical, but the practical issue is simple: the protection may not operate fast enough to prevent danger.

This fault can appear in older installations, incorrectly altered systems, or properties with earthing problems.

If your report mentions high Ze, loop impedance or poor disconnection times, use the EICR Code Cheatsheet to understand the observation before arranging remedial work.

Damaged Sockets and Switches

Damaged electrical accessories are another common reason for failed EICR reports.

Examples include:

• Cracked socket fronts
• Loose switches
• Burn marks
• Exposed conductors
• Broken faceplates
• Overheated accessories
• Poor DIY repairs

Depending on severity, these can be coded as C1, C2 or C3.

If live parts are accessible, it can become a C1 issue.

Plastic Consumer Units

A plastic consumer unit is not automatically a failed EICR issue. This is a common misunderstanding.

However, it can become a problem depending on location, condition, installation quality and signs of overheating or damage.

For example, a plastic consumer unit under wooden stairs or in an escape route may be treated more seriously than one in a lower-risk location. The final code depends on the inspection findings.

If you are unsure whether your consumer unit is likely to cause an issue, book an inspection through our online EICR booking page.

Bathroom Electrical Faults

Bathrooms are high-risk areas because water and electricity are close together.

Common bathroom EICR failures include:

• Incorrect light fittings
• No RCD protection
• Poorly located switches
• Unsafe extractor fan wiring
• Non-IP rated fittings in unsuitable zones
• Damaged pull cords
• Exposed or poorly protected wiring

Bathroom-related faults are often coded seriously because the shock risk is higher.

If your report mentions bathroom electrical faults, C2 observations or unsafe fittings, our EICR remedial work team can help with the next stage.

Exposed Conductors

Exposed conductors are a serious issue. If live parts can be touched, the observation may be coded as C1.

This needs immediate attention.

Common causes include:

• Damaged accessories
• Loose fittings
• Poor DIY work
• Removed covers
• Broken junction boxes
• Damaged cable insulation

If your report mentions exposed conductors, exposed live parts or danger present, treat it as urgent and arrange failed EICR remedial work.

Old Fuse Boards

Old fuse boards are common across London. The age of the fuse board alone does not always mean the report will fail, but old boards often lack modern protection.

Potential issues include:

• No RCD protection
• Rewireable fuses
• Poor labelling
• Overcrowded wiring
• Signs of heat damage
• No spare capacity
• Mixed old and new circuit arrangements

If the board cannot provide adequate protection, the report may fail.

For pricing guidance, see our EICR certificate cost in London page.

Overloaded Circuits

Overloaded circuits can create overheating and fire risks.

This is often found in properties where additional sockets, appliances or extensions have been added over time without proper electrical design.

Common examples include:

• Kitchens with too many high-load appliances on one circuit
• Office areas with overloaded socket outlets
• Shops with added equipment
• Flats with multiple extensions
• Converted properties with altered circuits

For businesses, see our commercial EICR certificates in London service page.

Poor DIY Electrical Work

DIY electrical work is one of the biggest causes of failed EICR reports.

Common signs include:

• Incorrect cable sizes
• Poor junction boxes
• No proper containment
• Mixed circuit wiring
• Loose terminations
• Incorrect polarity
• Unsafe additions
• No testing records

Even if the installation appears to work, it may still be unsafe.

If you have recently bought a property and suspect previous DIY electrical work, arrange a proper electrical installation condition report in London.

Why EICR Codes Matter for Landlords

For landlords, EICR codes are not just technical notes. They directly affect compliance.

If a rental property has an unsatisfactory EICR, the landlord normally needs to arrange remedial work and obtain written confirmation that the required works have been completed.

This matters because landlords have legal duties around electrical safety in rental properties.

An unsatisfactory EICR can also create practical problems:

• Tenancy delays
• Letting agent compliance issues
• Insurance concerns
• Tenant complaints
• Failed property management checks
• Urgent repair pressure
• Risk of enforcement action

If you are a landlord, visit our dedicated EICR certificates for landlords in London page.

Why Homeowners Should Also Understand EICR Codes

EICRs are not only for landlords. Homeowners can also benefit from understanding report codes, especially when buying, selling, renovating or checking an older property.

A homeowner may need an EICR when:

• Buying a property
• Selling a property
• Planning renovation work
• Checking old wiring
• Investigating electrical faults
• Preparing for insurance requirements
• Converting a property for rental use
• Upgrading an old fuse board

For owner-occupied properties, see our EICR certificates for homeowners in London page.

What Happens After a Failed EICR?

If your EICR has failed, the process is usually straightforward.

The next steps are:

• Review the report observations
• Identify whether the codes are C1, C2, C3 or FI
• Arrange remedial work for C1 and C2 issues
• Arrange further investigation for FI items
• Complete the required electrical repairs
• Obtain confirmation that the work has been completed
• Issue or update the satisfactory EICR where applicable

The key is not to panic, but not to ignore it either.

A failed EICR is often fixable. The important thing is to understand what failed, why it failed, and what work is needed to make the property safe.

If you are unsure how to read your report, use our guide on how to read and understand an EICR report.

Can You Rent a Property With a Failed EICR?

In most cases, a rental property should not be treated as compliant if the EICR is unsatisfactory.

If the report contains C1 or C2 observations, remedial work is usually required. If the report contains FI observations, further investigation may be needed before the installation can be confirmed as safe.

Landlords should act quickly because delays can affect:

• New tenancy start dates
• Letting agent approval
• Property management records
• Tenant safety
• Compliance documentation

If you need to book an inspection or arrange work quickly, use our book EICR online page.

How Much Does It Cost to Fix a Failed EICR?

The cost depends on the fault.

Some issues are simple and relatively low cost, such as replacing a damaged socket or fitting a correct accessory. Other issues are more involved, such as installing bonding, upgrading a consumer unit, tracing a fault, or correcting unsafe wiring.

Typical cost factors include:

• Number of failed observations
• Type of fault
• Property size
• Access conditions
• Consumer unit condition
• Age of wiring
• Whether fault finding is needed
• Whether parts need replacing
• Whether the property is residential or commercial

For a full service overview, see our remedial work for failed EICR certificates page.

If you want to understand inspection pricing first, visit our EICR certificate cost page.

Why You Should Not Ignore a C3 Code

C3 observations do not normally fail an EICR on their own, but they should still be taken seriously.

A C3 is often a sign that the installation is ageing or could be improved. If ignored long enough, the same issue may become more serious in a future inspection.

For example:

• Old accessories may deteriorate
• Missing labels may cause confusion during future work
• Older consumer units may become less suitable
• Lack of RCD protection may become a bigger concern
• Minor wear may develop into damage

C3 items are best handled as planned improvements rather than emergency repairs.

Why the EICR Code Cheatsheet Is Useful

Most property owners do not read EICR reports every day. The wording can be technical, and two similar-sounding faults can have very different meanings.

That is why we created our EICR Code Cheatsheet.

It helps users search common EICR observations and understand what the fault may mean in practical terms.

You can use it if your report mentions issues such as:

• C1 danger present
• C2 potentially dangerous
• C3 improvement recommended
• FI further investigation
• No RCD protection
• Missing bonding
• High Ze
• Bathroom light failed
• Damaged socket
• Plastic consumer unit
• Exposed conductors
• Unsafe earthing
• Old fuse board
• Poor insulation resistance

The aim is simple: help London property owners understand failed reports faster and take the right next step.

Residential vs Commercial EICR Failed Codes

The same coding system is used across different types of properties, but the risk profile can be different.

In a residential property, the concern is usually tenant or homeowner safety.

In a commercial property, the situation may involve:

• Employees
• Customers
• Visitors
• Insurance requirements
• Fire risk assessments
• Facilities management
• Business interruption
• Landlord and tenant responsibilities
• Multiple distribution boards
• Emergency systems
• Higher electrical loads

Commercial EICRs often require more planning because access, shutdowns and operational disruption may need to be managed properly.

If you operate a business premises, visit our commercial EICR certificate London page.

EICR Codes and Insurance

Electrical safety can affect insurance, especially after a fire, electrical incident, water leak affecting electrics, or tenant complaint.

A failed EICR can create questions such as:

• Was the installation safe?
• Were known faults repaired?
• Was remedial work completed?
• Was the certificate valid?
• Was the landlord or owner aware of the defect?
• Were recommended works ignored?

This is why keeping proper records matters. After remedial work, you should keep copies of reports, invoices, certificates and confirmation of completed works.

For broader guidance, read our article on how to read an EICR report and ensure electrical safety.

What Information Should You Send for a Failed EICR Quote?

If your EICR has failed and you want a quotation, sending the right information helps the process move faster.

Useful details include:

• Full property address
• Copy of the failed EICR report
• Photos of the consumer unit or fuse board
• Photos of any visible faults
• Property type
• Number of bedrooms or commercial size
• Access contact details
• Any tenant or agent requirements
• Preferred date for remedial work
• Whether a new satisfactory EICR is required after the work

You can contact us through the main website or book directly using our online EICR booking page.

How to Avoid a Failed EICR in Future

You cannot guarantee that a property will pass every future inspection, especially as electrical standards and installation conditions change over time. However, you can reduce the risk.

Practical steps include:

• Do not ignore previous C3 observations
• Avoid DIY electrical work
• Use qualified electricians for alterations
• Keep records of electrical works
• Replace damaged accessories quickly
• Check sockets and switches regularly
• Upgrade old consumer units where sensible
• Make sure bonding is present and accessible
• Arrange inspections before tenancy deadlines
• Deal with tenant-reported electrical issues quickly

If your property is due for testing, you can arrange an EICR certificate in London before the situation becomes urgent.

Why Choose London EICR Certificates?

London EICR Certificates helps landlords, homeowners, estate agents, property managers and commercial clients arrange electrical safety inspections across London.

We can help with:

• EICR inspections
• Failed EICR reports
• EICR remedial work
• Landlord electrical certificates
• Commercial EICR certificates
• Homeowner electrical safety checks
• EICR report explanations
• Re-testing after remedial work
• Fast London bookings

If your report has failed, we can help you understand the observations, quote for remedial work and arrange the next stage.

To see more about our company, visit London EICR Certificates. To check whether we cover your location, visit our areas we cover page.

Final Thoughts: Do Not Guess What Your EICR Code Means

A failed EICR should not be ignored, but it also should not be misunderstood.

The most important thing is to identify the code:

• C1 means danger is present
• C2 means potentially dangerous
• C3 means improvement recommended
• FI means further investigation required

If your report contains C1, C2 or FI observations, action is usually required before the installation can be treated as satisfactory.

For fast help, use our EICR Code Cheatsheet to understand the fault, then visit our failed EICR remedial work page if repairs are needed.

To arrange a new inspection, book through our EICR online booking page.