EICR Codes Explained: C1, C2, C3 and FI — What Each Code Means

An EICR report arrives and the first thing you see is a list of observations — each followed by a code: C1, C2, C3, or FI. You know the codes indicate severity. But which ones make the report fail? What does each one actually mean in practice? And what does a C2 mean for a landlord with a 28-day deadline?

This guide explains every EICR code in depth, maps real-world faults to specific codes, shows what remedial work costs for each level, and covers the property-sale and insurance implications that most guides skip.

💡 Understand faults before they happen. ElectraSim lets you build circuits and inject the same faults an EICR inspector looks for — reverse polarity, missing earths, absent RCD protection — and see exactly how each affects the circuit. Open ElectraSim →

What Is an EICR and What Are the Codes?

An Electrical Installation Condition Report (EICR) is a formal document produced by a qualified electrician after inspecting and testing the fixed electrical installation in a property. Every observation is assigned a condition code indicating its severity.

The four codes are:

A Satisfactory EICR means no C1 or C2 findings. An Unsatisfactory EICR means one or more C1 or C2 findings — remedial work is required before the installation can be re-tested and pass.

C1 — Danger Present

What it means

The installation has a defect that creates immediate risk of injury. The affected circuit or the entire installation should be isolated immediately — do not use it until the defect is corrected.

What faults produce a C1

What happens with C1

• The electrician should advise you to isolate the affected circuit immediately
• If the fault is on the consumer unit or supply cable, isolate the entire installation
• Do not reset the breaker or re-energise until the fault is corrected
• A C1 finding makes the EICR Unsatisfactory
• Landlords: immediate action — there is no 28-day grace period for C1; the circuit must be isolated or fixed on the spot

Typical remedial cost

How to simulate in ElectraSim

1. Place a Power Supply and Bulb in ElectraSim
2. Wire the switch into the neutral path (reverse polarity)
3. Toggle the switch off — the bulb goes dark but the live connection to the holder remains active
4. This demonstrates exactly why C1 exists: the holder is live at 230 V even when the switch is off

C2 — Potentially Dangerous

What it means

The installation has a defect that is not immediately dangerous but could become dangerous under certain conditions. Remedial action is required — the EICR is Unsatisfactory.

What faults produce a C2

What happens with C2

• The EICR is Unsatisfactory
• Remedial work is required
• Landlords: must complete remedial work within 28 days (or a shorter period if the report specifies)
• Homeowners: no legal deadline, but the installation is not safe for continued use without remediation
• A new EICR (or partial re-inspection) is required after remedial work to confirm the installation now passes

Typical remedial cost

📖 Related: Consumer Unit Upgrade: What to Expect When Replacing Your Fuse Board — a consumer unit upgrade is the most common C2 remedial work; this guide explains the full process and costs.

How to simulate in ElectraSim

1. Build a circuit with a Power Supply, Switch, and Bulb
2. Remove the earth connection from the circuit
3. The circuit continues to operate normally — the missing earth is invisible in normal use
4. Add an RCD and inject an earth fault — the RCD trips; without the RCD, the fault persists undetected
5. This demonstrates why “no RCD protection” is a C2: the MCB does not detect earth leakage

C3 — Improvement Recommended

What it means

The installation does not comply with the current edition of BS 7671, but it may have complied when originally installed. The defect is not dangerous and does not make the EICR Unsatisfactory — but improvement is recommended.

What faults produce a C3

What happens with C3

• A C3 finding does not make the EICR Unsatisfactory
• The report can still receive a Satisfactory result with C3 observations
• Remedial work is not legally required but is recommended
• Best practice: address C3 findings when the installation is next worked on, or when budget allows
• Multiple C3 findings can indicate an aging installation that may receive C2 findings at the next inspection as conditions deteriorate

Typical remedial cost

Budgeting multiple C3 findings

A property with 4–6 C3 findings might have a total remedial cost of £300–£800. This is not urgent, but if the property is being sold or remortgaged, addressing C3 findings before a buyer’s solicitor asks questions can prevent delays. A seller’s solicitor requesting a copy of the EICR and finding C3 observations may prompt the buyer to request a price reduction.

FI — Further Investigation Required

What it means

The inspector could not fully assess a particular aspect of the installation. The code does not indicate severity — it indicates incompleteness. The investigation was stopped before a conclusion could be reached.

What faults produce an FI

What happens with FI

• The EICR cannot receive a final verdict on that aspect of the installation until the investigation is complete
• In practice, an FI item usually does not prevent the overall EICR from being Satisfactory or Unsatisfactory on the other observations — but the inspector will note that the installation cannot be fully certified without resolving the FI
• The homeowner or landlord should arrange for the investigation to be completed
• Once the FI is investigated, the inspector issues a 补充 (supplementary) report or a partial re-inspection noting the outcome
• An FI finding is not a code that makes the EICR Unsatisfactory — but it means the report is incomplete

Typical cost to resolve FI

How Codes Appear on a Real EICR Report

An EICR report is structured into several sections. The codes appear in the Observations table:

┌─────────────────────────────────────────────────────────────────────┐
│  OBSERVATIONS                                                       │
├────┬──────┬─────────────────────────────────────────────────────────┤
│ #  │ Code │ Description                                            │
├────┼──────┼─────────────────────────────────────────────────────────┤
│ 1  │ C2   │ No RCD protection on the downstairs socket circuit.    │
│    │      │ Board is a 1980s split-load with no RCBOs.             │
├────┼──────┼─────────────────────────────────────────────────────────┤
│ 2  │ C2   │ Missing main bonding to the gas meter installation.   │
│    │      │ Gas pipe is metallic; no 10 mm² CPC visible.           │
├────┼──────┼─────────────────────────────────────────────────────────┤
│ 3  │ C3   │ Consumer unit labels are illegible. Circuit            │
│    │      │ identification is not possible at the board.            │
├────┼──────┼─────────────────────────────────────────────────────────┤
│ 4  │ C3   │ No supplementary bonding in the bathroom. RCD         │
│    │      │ protection is present; bonding is recommended only.     │
├────┼──────┼─────────────────────────────────────────────────────────┤
│ 5  │ FI   │ Downstairs lighting circuit routes behind the          │
│    │      │ kitchen plasterboard could not be confirmed.            │
└────┴──────┴─────────────────────────────────────────────────────────┘

OVERALL RESULT: Unsatisfactory (C2 findings present)

In this example:

• Observation 1 (C2) and 2 (C2) make the report Unsatisfactory
• Observations 3 and 4 (C3) are recommended improvements but do not affect the result
• Observation 5 (FI) means the inspector could not fully assess one aspect

Code Combinations and What They Mean

The 28-Day Landlord Deadline

For landlords in England, Scotland, and Wales, the 28-day remedial deadline is one of the most important parts of the EICR process:

Important: The 28-day clock starts on the date of the EICR, not the date you received the report. If the EICR was dated 1 June and you received it on 5 June, the deadline is 29 June.

Failure to comply with the 28-day deadline for C1/C2 findings can result in:

• Civil penalty of up to £30,000 (England)
• Improvement notice from the local authority
• Rent repayment order (in serious cases)
• Prosecution under the Housing Act 2004 (England) or equivalent legislation in Scotland/Wales

What Happens If You Ignore a C2

During the tenancy

The local authority can serve an improvement notice requiring remedial work within a specified period. Non-compliance with an improvement notice is a criminal offence — fine of up to £5,000, plus a daily fine of up to £500 for continued non-compliance.

At the next EICR

The same C2 finding will appear again at the next inspection (5 years for landlords), and may have worsened. A missing earth that was C2 in 2026 may become C1 in 2031 if the insulation degrades further.

When selling the property

The buyer’s solicitor will request the EICR. A C2 finding that has not been remediated will:

• Be flagged as a pre-contract enquiry query
• Prompt the buyer to request remedial work or a price reduction
• May cause the buyer’s mortgage lender to refuse the loan (some lenders require a Satisfactory EICR)
• May cause the buyer’s insurer to refuse cover or increase premiums

Insurance

If a fire or electrical incident occurs and the insurer discovers an unremediated C2 finding from a previous EICR, they can:

• Refuse the claim (breach of policy condition — “maintain the installation in a safe condition”)
• Pay the claim but pursue recovery from the landlord/homeowner
• Cancel the policy

Remedial Work Process After a Failed EICR

1. Review the observations — understand each C1/C2 finding
2. Prioritise C1 findings — isolate immediately if not already done
3. Get quotes — you can use any Part P-registered electrician, not necessarily the one who did the EICR
4. Complete remedial work within 28 days (landlords) or as soon as practical (homeowners)
5. Obtain an EIC (Electrical Installation Certificate) for any new work carried out
6. Request a partial re-inspection — the original EICR inspector re-tests the affected circuits and issues a supplementary report confirming the C1/C2 findings have been resolved
7. Update your records — file the EIC and supplementary report alongside the original EICR

📖 Related: Consumer Unit Upgrade: What to Expect When Replacing Your Fuse Board — upgrading a consumer unit is the most common remedial action after an Unsatisfactory EICR.

How Each Code Affects Property Sales

Best practice for sellers: Obtain an EICR at least 6 months before listing the property. Address any C1/C2 findings. A Satisfactory EICR with no C1/C2 findings and no FI is the cleanest outcome for conveyancing.

EICR Codes vs PAT Testing: Don’t Confuse Them

EICR codes (C1/C2/C3/FI) apply to the fixed installation — the wiring, consumer unit, and accessories. They are completely separate from PAT testing (Portable Appliance Testing), which tests movable equipment like kettles, toasters, and power tools.

PAT testing has its own pass/fail system — there are no C1/C2 codes. A failed PAT test means the specific appliance is unsafe, not the building’s wiring.

📖 Related: PAT Testing Explained: Portable Appliance Testing for Landlords and Businesses

Frequently Asked Questions

Can I remediate C2 findings myself?

Part P allows non-notifiable work to be carried out by a competent person. However, most C2 findings involve work on the consumer unit, new circuits, or work in special locations — all of which are notifiable under Part P. In practice, C2 remedial work must be carried out by a registered competent person or notified to Building Control.

How long is an EICR valid?

There is no fixed expiry date. The IET recommends 10 years for owner-occupied homes and 5 years for rented properties. The inspector specifies the re-inspection interval on the report.

Does a Satisfactory EICR mean my wiring is perfect?

No. A Satisfactory EICR means no C1 or C2 findings were found at the time of inspection. The installation may have C3 recommendations or may deteriorate over time. It is a snapshot, not a guarantee.

What is the difference between an EICR and an EIC?

An EICR is an inspection report assessing the condition of an existing installation. An EIC (Electrical Installation Certificate) is issued for new work — a new circuit, a consumer unit replacement, or any notifiable installation work. They serve different purposes.

Can I get a partial re-inspection instead of a full EICR?

Yes. If only specific circuits were affected by C1/C2 findings, the inspector can re-test just those circuits and issue a supplementary report. This is cheaper and faster than a full re-inspection.

What if my EICR has both C2 and FI findings?

The C2 must be remediated (28 days for landlords). The FI must also be investigated before the installation can be fully certified. Both need to be addressed, but the C2 has the legal deadline.

Quick Reference: EICR Code Summary

Simulate Faults in ElectraSim

ElectraSim lets you build circuits and inject the exact faults an EICR inspector looks for — so you can understand what each code means before receiving a report:

Reverse polarity (would be C1):

1. Place a Power Supply, Switch, and Bulb
2. Wire the switch into the neutral path
3. Toggle the switch off — the bulb goes dark but the holder is still live
4. This demonstrates why C1 exists: the holder is at 230 V even when the switch is off

Missing earth (would be C2):

1. Add a Bulb connected to a Power Supply
2. Remove the earth connection
3. The circuit operates normally — the missing earth is invisible until a fault occurs
4. Add an RCD and inject an earth fault — the RCD trips; without the RCD, the fault persists

Open ring (would be C2):

1. Build a ring circuit with two paths from the distribution board
2. Break one leg by removing a wire mid-loop
3. All loads remain powered — the fault is invisible to normal operation but present in the wiring

🔍 ElectraSim’s simulation engine performs a full graph traversal on every circuit change — the same logical analysis an electrician applies during testing. Try it free →

Want to Understand Your EICR Better?

If you have received an EICR and are unsure what the codes mean, use ElectraSim to build a model of your own installation and explore each fault type. Understanding the why behind each code makes it easier to discuss remedial work with your electrician, prioritise spending, and avoid paying for unnecessary work. Open ElectraSim →