EICR codes are the classification codes used on an Electrical Installation Condition Report to show how serious an electrical issue is and what action needs to be taken. If you have searched for EICR classification codes, EICR fault codes, EICR observation codes, or what C1, C2, C3 and FI actually mean, this guide explains the full topic clearly.
For landlords, homeowners, letting agents and businesses, understanding EICR codes matters because the report outcome affects safety, remedial work, compliance decisions and, in some cases, legal responsibilities. The coding system used on EICRs is based around four standard classifications: C1, C2, C3 and FI. C1 means danger present, C2 means potentially dangerous, C3 means improvement recommended, and FI means further investigation required.
If you are new to the topic, it also helps to understand what an EICR certificate is before looking at the coding system. If you are arranging an inspection, it is also worth checking whether any electrician can do an EICR before you book.
Last Updated: 2026
Reviewed By: London Safety Certificate Compliance Team
Key Takeaways
- C1 means danger present and immediate action is required.
- C2 means potentially dangerous and urgent remedial work is needed.
- C3 means improvement recommended.
- FI means further investigation required.
- If an EICR contains C1, C2 or FI, the overall report is unsatisfactory.
- If a report contains only C3 observations, it can still be satisfactory.
Table of Contents
What are EICR Codes?
An EICR is a report on the condition of the fixed electrical installation at the time of inspection. It is not a certificate and it is not a quotation for remedial work. The report records observed damage, deterioration, defects, dangerous conditions and non-compliances that may give rise to danger, and each relevant observation is given a classification code.
Why EICR Codes Matter
The codes matter because they turn technical findings into a clear safety outcome. They show whether the issue is dangerous now, potentially dangerous, advisory only, or something that needs more investigation before the safety position can be confirmed. That makes them important not just for electricians, but also for landlords and property owners who need to know what must be fixed urgently and what is only recommended.
C1 – Danger Present
A C1 code means danger present. Immediate remedial action is required because there is a real and current risk of injury. This is the most serious classification on an EICR.
A C1 observation may be used where there are exposed live parts, severe damage creating immediate shock risk, or another defect that presents clear danger straight away. In some cases, the inspector may make the situation safe before leaving if that can be done safely. A C1 always makes the report unsatisfactory.
C2 – Potentially Dangerous
A C2 code means potentially dangerous. The defect may not be causing immediate harm at that exact moment, but there is enough risk that urgent remedial action is required.
Typical C2 issues can include poor earthing or bonding, defects that increase shock risk, overheating concerns, or other faults that could become dangerous if left unresolved. A C2 also makes the report unsatisfactory.
C3 – Improvement Recommended
A C3 code means improvement recommended. This does not mean the item is dangerous or potentially dangerous. It means the installation could be improved to provide a better level of safety or to align more closely with current standards.
This is one of the most misunderstood codes. A C3 on its own does not make the report unsatisfactory. It is advisory. Many older installations receive C3 observations because they are not fully up to the latest standard, even though the issue is not judged dangerous on that point alone.
FI – Further Investigation Required
FI means Further Investigation Required. This is used where the inspector cannot reach a clear conclusion on safety from the inspection and testing already carried out, and more investigation is needed without delay.
FI is not a minor note. It means the issue needs proper follow-up before the safety position can be confirmed. If FI appears on the report, the overall result is unsatisfactory until the matter is investigated and resolved.
What Makes an EICR Unsatisfactory?
An EICR is classed as unsatisfactory if it contains:
- C1
- C2
- FI
If the report contains only C3 observations, it can still be classed as satisfactory. That is the clearest way to understand report outcome.
EICR Code Examples
A simple way to understand the codes is to look at how they work in real situations.
- C1 example: A dangerous defect such as exposed live conductors that can be touched. This presents immediate risk and requires urgent action.
- C2 example: A defect that is not causing immediate harm at that second, but creates a meaningful risk if left in service. This still needs urgent remedial work.
- C3 example: An item that is not dangerous, but would benefit from improvement or upgrading.
- FI example: A situation where the inspector has found something concerning, but cannot safely or accurately confirm the full issue without additional investigation. The exact code depends on the actual level of risk found during inspection, not just the defect name on its own.
Do RCD Issues Fail an EICR?
Sometimes they do, and sometimes they do not. RCD-related observations are risk-based. Guidance used for coding makes clear that the absence of additional RCD protection can be coded differently depending on the actual circumstances and the level of danger. In some situations it may justify C2. In others it may be C3.
So the correct answer is that an RCD issue does not have one automatic code in every property. The final classification depends on the way the circuit is used and the real safety risk identified by the inspector. If you want the inspection side explained in more detail, read our guide to EICR test procedure.
Are Older Installations an Automatic Fail?
No. An older installation is not automatically unsatisfactory just because it does not match the latest edition in every respect. Guidance on condition reporting makes clear that existing installations may not comply fully with the current edition, but that does not automatically mean they are unsafe for continued use or require upgrading.
That is why some older items receive C3, while more serious issues receive C2 or C1. The code depends on safety risk, not just age.
Common Issues That Trigger EICR Codes
Common issues that can lead to observations on an EICR include:
- Exposed live parts
- Damaged accessories
- Overheating signs
- Poor earthing or bonding
- Missing or unsuitable protective measures
- Deteriorated insulation
- Unsafe alterations or poor-quality DIY work
- Faults that cannot be fully diagnosed during the initial inspection
These can be coded differently depending on the severity of the defect and the level of risk.
What Landlords Should Do After an Unsatisfactory EICR
For landlords in England, the guidance says the electrics in rented properties must be inspected and tested at least every 5 years by a properly qualified person. If the report requires remedial work or further investigation, that work must be completed within 28 days or within the shorter period stated in the report, and written confirmation must then be supplied. If you are unsure about the landlord side of compliance, read whether an electrical safety certificate is a legal requirement for landlords.
So if your report contains C1, C2 or FI, do not treat it like a minor recommendation. Review the findings properly, arrange the required work quickly, and keep the paperwork organised. If you want to see how these observations appear on the paperwork, look at this EICR report example.
What to Do After You Receive the Report
If the report is satisfactory, keep it on file and follow the recommended next inspection date. If the report is unsatisfactory, check which codes have been used. If the report contains C1, C2 or FI, arrange remedial work or further investigation without delay.
If the report contains only C3 observations, review the recommendations sensibly. They are not classed as dangerous, but they may still be worth doing to improve the installation and reduce future risk.
Frequently Asked Questions
What does C1 mean on an EICR?
C1 means danger present. Immediate action is required because there is a current risk of injury.
Is C2 a fail on an EICR?
A C2 makes the overall report unsatisfactory because it indicates a potentially dangerous defect that needs urgent remedial work.
What does C3 mean on an EICR?
C3 means improvement recommended. It is advisory and does not automatically make the report unsatisfactory.
What does FI mean on an EICR?
FI means Further Investigation Required. It shows that the inspector could not confirm safety without more investigation, and it makes the report unsatisfactory until resolved.
What EICR codes are unsatisfactory?
C1, C2 and FI make a report unsatisfactory. A report with only C3 observations can still be satisfactory.
Are EICR fault codes the same as EICR observation codes?
Usually yes. They are different ways people refer to the same coding system used on the report.
Does a missing RCD always fail an EICR?
No. The code depends on the actual circumstances and level of risk.
Does an old installation automatically fail?
No. The final code depends on the actual safety risk, not just the age of the installation.
Final Word
The simplest way to understand EICR codes is this:
- C1 = danger present
- C2 = potentially dangerous
- C3 = improvement recommended
- FI = further investigation required
Once you understand those four codes, it becomes much easier to read an EICR report properly, understand whether the result is satisfactory or unsatisfactory, and decide what needs to happen next.