EICR Codes Explained: C1, C2, C3, and FI

When you receive an Electrical Installation Condition Report (EICR), every defect or observation is classified with a code that indicates how serious it is and how urgently it needs fixing. Understanding these codes is essential for landlords, property managers, and business owners to ensure compliance and safety.

Understanding EICR classification codes

Every issue identified during an EICR inspection is classified using a standard coding system defined in BS 7671 (the UK Wiring Regulations). These codes tell you:

• How serious the defect is
• How urgently it needs to be addressed
• Whether your EICR result will be satisfactory or unsatisfactory
• What action you need to take

The four main classification codes are:

• C1 — Danger present (immediate risk)
• C2 — Potentially dangerous (urgent remedial action required)
• C3 — Improvement recommended (advisory)
• FI — Further investigation required

C1 - Danger present

What it means

A C1 classification indicates there is immediate danger present. The defect poses a direct risk of electric shock, fire, or injury right now.

Official definition: "Danger present. Risk of injury. Immediate remedial action required."

Why it's serious

C1 defects mean someone could be injured or killed if they use the electrical installation. These are not theoretical risks — they are clear and present dangers that require immediate action.

Common C1 defects

Live parts accessible:

• Exposed live conductors you could touch
• Missing covers on junction boxes or consumer units
• Damaged accessories with live parts visible
• Broken sockets or switches revealing internal connections

Critical safety failures:

• Complete absence of earthing
• Missing or bypassed protective devices (circuit breakers or RCDs)
• Severely damaged cables with exposed conductors
• Inappropriate or dangerous DIY electrical work

Dangerous installations:

• Overheated or burnt consumer units
• Cables or connections showing severe damage or deterioration
• Metalwork that should be earthed but isn't (like metal consumer unit cases)
• Circuits operating with no overcurrent protection

What you must do

Immediate action:

1. Stop using the installation — Do not use the affected circuit or system
2. Isolate if safe to do so — The electrician may isolate the dangerous circuit immediately
3. Arrange emergency repair — Contact a qualified electrician the same day
4. Do not delay — This is a genuine emergency

For landlords:

• You cannot let property with unresolved C1 defects
• If discovered during a tenancy, isolate the circuit and arrange immediate repair
• Inform tenants not to use the affected circuits
• Complete repairs before anyone uses the installation again

For businesses:

• Isolate the affected area if possible
• Prevent access to dangerous circuits
• Arrange immediate repair
• Consider whether you can operate safely while repairs are made

Examples of C1 defects in practice

Example 1: Exposed live parts

• Damaged socket with internal connections accessible
• Risk: Someone could touch live conductors and receive a fatal electric shock
• Action: Isolate circuit immediately, replace socket same day

Example 2: No earthing protection

• Consumer unit has no main earthing conductor
• Risk: Metal parts could become live during a fault with no protection
• Action: Do not use installation, install earthing system urgently

Example 3: Missing RCD protection for bathroom circuit

• Bathroom lighting circuit has no RCD protection
• Risk: Electric shock in a high-risk location (water present)
• Action: Isolate circuit, install appropriate RCD protection immediately

C2 - Potentially dangerous

What it means

A C2 classification indicates the defect is potentially dangerous. While not presenting immediate danger under normal conditions, it could become dangerous if a fault occurs or in certain circumstances.

Official definition: "Potentially dangerous. Urgent remedial action required."

Why it matters

C2 defects are serious. They don't pose an immediate risk right this second, but they could quickly become dangerous. Think of them as ticking time bombs — safe now, but dangerous if conditions change or a fault develops.

Common C2 defects

Inadequate protection:

• Insufficient earthing or bonding
• Missing or inadequate RCD protection
• Wrong type or rating of protective device
• Lack of fire barriers in consumer unit

Unsafe installations:

• Cables installed in ways that could cause damage
• Inadequate protection against electric shock
• Overloaded circuits
• Non-compliant additions or alterations

Deterioration issues:

• Old rubber or fabric-insulated cables still in use
• Corroded or damaged earthing connections
• Evidence of overheating (but not currently dangerous)
• Accessories showing signs of age-related failure

Compliance issues:

• Circuits requiring but lacking RCD protection under current standards
• Missing supplementary bonding in bathrooms or special locations
• Inadequate fault protection levels
• Consumer units made of combustible materials (pre-2016 plastic)

What you must do

For landlords (legal requirement):

• Complete remedial work within 28 days of the inspection
• Or before a new tenant moves in (whichever is earlier)
• Provide a copy of the remedial works certificate to tenants within 28 days of completion
• You cannot start a new tenancy with unresolved C2 defects

For businesses:

• Arrange remedial work as soon as reasonably practicable
• Typically within 28 days
• Consider your duty of care to employees and visitors
• Check your insurance requirements

For homeowners:

• Recommended to fix within 1-3 months
• Do not ignore these defects
• They will become worse over time
• May affect house sales or insurance

Timeframes explained

Why 28 days for landlords?

This is the legal deadline set by the Electrical Safety Standards in the Private Rented Sector (England) Regulations 2020. It balances urgency with practicality — giving time to arrange work but ensuring dangerous conditions aren't left indefinitely.

What if you can't complete work in 28 days?

• Document genuine reasons for delay (e.g., parts on order, access issues)
• Keep tenants informed
• Arrange work as soon as possible
• Be aware that lack of compliance exposes you to fines
• Local authorities may not accept delays without good reason

Examples of C2 defects in practice

Example 1: Inadequate main earthing conductor

• Earthing conductor undersized for the installation
• Risk: May not operate quickly enough in a fault, allowing sustained dangerous voltages
• Action: Replace with correctly sized conductor within 28 days

Example 2: Socket circuits without RCD protection

• Sockets don't have required RCD protection under current standards
• Risk: Increased risk of fatal electric shock from damaged appliances or cables
• Action: Install RCD protection (RCBO or split-load consumer unit) within 28 days

Example 3: Damaged cable insulation

• Cable showing wear but not yet exposing conductors
• Risk: Could deteriorate further and cause shock or fire
• Action: Replace damaged cable within 28 days

C3 - Improvement recommended

What it means

A C3 classification is an advisory recommendation. The item doesn't meet current best practice or standards, but it's not dangerous.

Official definition: "Improvement recommended."

Why it's included

Electrical standards evolve over time. Something that was acceptable when installed may not meet current standards but isn't inherently dangerous. C3 codes highlight these items so you can consider addressing them during planned maintenance.

Common C3 defects

Non-critical improvements:

• Old wiring in good condition but not to current edition of BS 7671
• Lack of labeling on consumer unit circuits
• Missing circuit charts or schedules
• Outdated but functioning equipment

Best practice recommendations:

• Upgrading to current protection standards (advisory)
• Improving documentation
• Adding surge protection (recommended but not required)
• Enhancing circuit identification

Age-related observations:

• Installations compliant with older standards
• Equipment approaching end of useful life but still safe
• Recommendations for future upgrades

What you should do

C3 codes do not require urgent action. However, consider:

Plan for improvements:

• Address C3 items during planned renovations or maintenance
• Budget for upgrades over time
• Consider doing them when other electrical work is being carried out

For landlords:

• Not required to be fixed to achieve a satisfactory EICR
• Good practice to address them over time
• May improve tenant satisfaction and property value
• Consider them when planning property improvements

For businesses:

• Review C3 recommendations in context of your risk management
• Address them during routine maintenance windows
• Some may become requirements in future regulation updates

For homeowners:

• No immediate action needed
• Consider them when renovating or upgrading
• Good practice for long-term property maintenance

Examples of C3 defects in practice

Example 1: No circuit labeling

• Consumer unit circuits not clearly labeled
• Risk: None directly, but makes isolation difficult in emergencies
• Action: Label circuits at next convenient opportunity

Example 2: Old but functional wiring

• Installation from 1980s, meets standards of that era, still in good condition
• Risk: None currently, but approaching end of life
• Action: Plan for eventual rewire in next 10-15 years

Example 3: Recommended surge protection

• No surge protection device fitted (not required but recommended)
• Risk: Equipment could be damaged by power surges
• Action: Consider adding surge protection when budget allows

FI - Further investigation required

What it means

An FI code indicates the inspector could not fully inspect or test something, and further investigation is needed to determine if there's a defect.

Official definition: "Further investigation required without delay."

Why it's used

Sometimes electricians can't fully access or test part of an installation during an EICR:

Access limitations:

• Areas that couldn't be accessed (locked rooms, tenants' cupboards)
• Circuits concealed in areas that can't be inspected without damage
• Parts of the installation behind fixtures that couldn't be removed

Testing limitations:

• Circuits that couldn't be powered down due to critical equipment
• Systems requiring specialist knowledge or equipment
• Installations with incomplete documentation

Observations requiring investigation:

• Signs of faults that need specialist investigation
• Unusual readings that need further diagnosis
• Potential issues that couldn't be confirmed during the inspection

What you must do

Arrange investigation promptly:

1. Within days, not months — "Without delay" means urgent investigation
2. Provide full access — Arrange for the electrician to access all areas
3. Allow testing — Ensure circuits can be powered down if needed
4. Follow up findings — If defects are identified, treat them according to their classification

For landlords:

• An EICR with FI codes is technically incomplete
• You must arrange for the investigation to be completed
• If C1 or C2 defects are found, the 28-day clock starts from that discovery
• Provide full access to complete the inspection

For businesses:

• Schedule investigation around operations if possible
• But don't delay excessively
• Unknown issues could be C1 or C2 defects
• Your duty of care requires you to investigate

Examples of FI codes in practice

Example 1: Inaccessible junction box

• Junction box visible in loft but concealed under insulation
• FI reason: Could not access to inspect connections
• Action: Remove insulation, allow electrician to inspect, replace insulation

Example 2: Tenant's locked bedroom

• Circuits in tenant's room couldn't be tested (access refused)
• FI reason: Could not test sockets or lighting in that room
• Action: Arrange access with tenant, complete inspection

Example 3: Unusual test readings

• Test readings indicate possible fault but can't be confirmed without further investigation
• FI reason: Needs specialist investigation to determine cause
• Action: Engage electrician to investigate, may need cable tracing or thermal imaging

Satisfactory vs Unsatisfactory results

What makes an EICR satisfactory?

An EICR is classified as satisfactory when:

• No C1 codes are present (or all have been remedied)
• No C2 codes are present (or all have been remedied)
• Any C3 codes are advisory only
• FI codes have been investigated and resolved

A satisfactory EICR means your electrical installation is safe to continue using in its current condition.

What makes an EICR unsatisfactory?

An EICR is classified as unsatisfactory when:

• Any C1 code is present
• Any C2 code is present
• FI codes remain unresolved

Even one C1 or C2 code makes the entire EICR unsatisfactory, regardless of how many items are satisfactory.

What to do with an unsatisfactory EICR

Step 1: Understand what needs fixing

Read through the report carefully. Make a list of all C1 and C2 codes. The electrician should have explained these during the inspection, but if anything's unclear, ask for clarification.

Step 2: Prioritize the work

• C1 defects — Stop using affected circuits, fix immediately
• C2 defects — Arrange urgent repair (28 days for landlords)
• FI codes — Arrange investigation to determine if defects exist
• C3 codes — Note for future reference, not urgent

Step 3: Get quotes for remedial work

• The electrician who did the EICR can usually quote for repairs
• You can get multiple quotes from qualified electricians
• Make sure they understand they're quoting to remedy specific EICR codes
• Keep all documentation

Step 4: Complete the work

• Use qualified electricians (registered with competent person schemes)
• Ensure they provide certification for completed work
• Keep invoices and certificates
• Photograph before and after if significant work is done

Step 5: Confirm the repairs

After remedial work is complete, you need confirmation. This can be:

• Electrical Installation Certificate (EIC) — If new circuits were installed
• Minor Electrical Installation Works Certificate (MEIWC) — For smaller repairs
• Condition Report Confirmation — Electrician confirms specific defects are remedied
• Repeat EICR — Full re-inspection showing all codes cleared (most thorough option)

Remedial work timeframes summary

Real-world scenarios

Scenario 1: Landlord receives EICR with mix of codes

The situation: A landlord commissions an EICR before a new tenancy. The report identifies:

• One C1 code: Exposed live parts in garage consumer unit
• Three C2 codes: Missing RCD protection, inadequate bonding, damaged cable
• Five C3 codes: No circuit labeling, old-style socket faceplates, recommended improvements

The result: Unsatisfactory

What the landlord must do:

1. C1 code — Isolate garage circuit immediately, arrange emergency repair
2. C2 codes — All must be fixed within 28 days (before new tenancy starts)
3. C3 codes — Not required to be fixed, but good practice to address some
4. Cannot let property until C1 and C2 defects are remedied
5. Provide remedial certificates to new tenant within 28 days of completion

Scenario 2: Business premises with C2 codes

The situation: A small office receives an EICR showing:

• Two C2 codes: Inadequate earthing, overloaded circuit
• Seven C3 codes: Various improvements recommended
• No C1 codes

The result: Unsatisfactory

What the business must do:

1. C2 codes — Arrange remedial work urgently (within 28 days recommended)
2. Continue operating — Installation not immediately dangerous, but work needed
3. Insurance — Notify insurer, check if coverage affected
4. Employees — Consider duty of care, don't delay repairs
5. C3 codes — Plan to address during next maintenance schedule

Scenario 3: Homeowner with only C3 codes

The situation: A homeowner gets an EICR before selling. The report shows:

• No C1 or C2 codes
• Eight C3 codes: Outdated consumer unit, old wiring, recommendations for improvements

The result: Satisfactory

What the homeowner should consider:

1. Installation is safe — Can continue using as-is
2. Sale not affected — Satisfactory EICR supports sale
3. Buyer may ask — About C3 items, be prepared to discuss
4. Consider addressing some — May improve sale value or speed
5. Not required — But could be selling point if you fix key items

Scenario 4: FI code requires follow-up

The situation: An EICR identifies an FI code: Unable to access all circuits in extension due to built-in furniture.

The result: Incomplete

What must happen:

1. Arrange access — Remove or move furniture to allow inspection
2. Complete inspection — Electrician returns to test those circuits
3. If defects found — Classified as C1, C2, or C3 and dealt with accordingly
4. If no defects — EICR can be updated to satisfactory (if no other codes)
5. Don't assume it's fine — Until investigation completed, status unknown

Common questions about EICR codes

How to prevent future code classifications

Regular maintenance

Proactive approach:

• Commission EICRs at the recommended intervals
• Address minor issues before they become C2 defects
• Keep documentation of all electrical work
• Use qualified electricians for all installations and alterations

Early intervention:

• Don't ignore warning signs (flickering lights, tripping circuits)
• Address C3 recommendations during planned maintenance
• Replace aging equipment before it fails
• Keep installations clean, dry, and well-ventilated

Quality electrical work

Always use qualified electricians:

• Registered with NICEIC, NAPIT, ELECSA, or other competent person schemes
• Request certificates for all work
• Verify qualifications before engaging
• Check reviews and references

Avoid DIY electrical work:

• Most electrical work requires Building Regulations approval
• Incorrect work creates dangerous conditions
• DIY work often leads to C1 or C2 codes at next EICR
• Can affect insurance and property sales

For landlords: Building compliance into your process

Create an electrical safety schedule:

• Diarize EICR renewals 3 months before expiry
• Address remedial work immediately
• Keep digital and physical copies of all certificates
• Include electrical safety in property handover processes

Educate tenants:

• Explain what an EICR is and why it's important
• Provide copies promptly (within 28 days)
• Encourage reporting of electrical issues
• Include electrical safety in tenant information packs

Budget for electrical safety:

• Set aside funds for EICRs and remedial work
• Don't defer electrical maintenance
• Consider replacing aging installations proactively
• Factor electrical safety into property investment decisions

What good looks like: Achieving a satisfactory EICR

Before the EICR

Prepare your property:

• Ensure full access to all areas
• Remove obstacles blocking consumer unit, sockets, and circuits
• Have previous electrical certificates available
• Inform tenants if applicable

Choose the right electrician:

• Registered with competent person scheme
• Qualified for inspection and testing (C&G 2391 or equivalent)
• Clear pricing and report turnaround time
• Professional indemnity insurance

During the EICR

Support the inspection:

• Provide access to all areas
• Answer questions about the installation history
• Allow adequate time (2-4 hours for typical domestic property)
• Don't rush the electrician

After the EICR

If satisfactory:

• Store certificate safely for 5 years
• Provide copy to tenants within 28 days (landlords)
• Diarize next inspection
• Consider addressing C3 recommendations during future work

If unsatisfactory:

• Act on C1 codes immediately
• Arrange C2 remedial work urgently (within 28 days for landlords)
• Get proper certification for all work
• Confirm all defects remedied

Next steps

Now you understand EICR codes, learn more about the inspection itself:

What is an EICR? →

Find out if you're required to have an EICR:

Do I need an EICR? →

Understand your full electrical safety obligations as a landlord:

Landlord electrical safety requirements →

Related articles:

• What is an EICR?
• Do I need an EICR?
• Landlord electrical safety requirements
• PAT testing vs EICR

Useful tools:

• Compliance Checker
• Electrical Safety Self-Check