EICR codes explained, and how they decide the outcome

EICR observations are coded C1 (danger present, immediate remedial action necessary), C2 (potentially dangerous, urgent remedial action necessary), C3 (improvement recommended) and FI (further investigation is advised). Under BS 7671:2018+A4:2026, published 15 April 2026, a C1 or C2 makes the overall assessment Unsatisfactory. C3 and FI are advisory and do not affect it. Before Amendment 4 an FI also made a report Unsatisfactory, so reports and guidance written under earlier editions read differently.

Sources last checked 19 October 2026.

The four codes

The wording below is from the IET's A4:2026 model EICR.

• C1: Danger present. Risk of injury. Immediate remedial action is necessary.
• C2: Potentially dangerous. Urgent remedial action is necessary.
• C3: Improvement recommended.
• FI: Further investigation is advised.

How the codes decide the outcome

Section E of the report states whether the installation is Satisfactory or Unsatisfactory in terms of suitability for continued service. The form says an unsatisfactory assessment indicates that dangerous (C1) and/or potentially dangerous (C2) conditions have been identified. It also says any observation coded C3 or FI is advisory and does not affect the overall assessment, but should be given due consideration.

That is a change. NICEIC's Amendment 4 guidance says that under Amendment 3 an FI made the report unsatisfactory, and that the earlier FI wording, further investigation required without delay, has been replaced by further investigation is advised. A report issued under the earlier edition was assessed under that edition's rules, and guidance published before 2026 may still describe the old position.

What each code means in practice

The notes on the form say that where practicable, C1 items are to be made safe on discovery. Where that is not possible, the owner or user is to be given written notification as a matter of urgency. For C1 the recipient guidance says the safety of those using the installation is at risk and a competent person should do the remedial work immediately. For C2 it says the safety of users may be at risk and the work should be done as a matter of urgency.

C3 is advisory only. The notes say remedial work may improve the safety of the installation, but a C3 does not affect the overall assessment.

FI is for something the inspection identified that the inspector cannot classify until further investigation has taken place, for example because of the agreed extent and limitations. The form says to record it in Section K as FI. It is not a way to avoid making a call on something you could have verified. Which code applies is the inspector's professional judgement.

Rented homes in England

The Electrical Safety Standards in the Private Rented Sector (England) Regulations 2020 require a landlord to have the electrical installation inspected and tested by a qualified person at intervals of no more than five years, or sooner if the most recent report says so. Where the report shows further investigative or remedial work is required, the landlord must have it carried out by a qualified person within 28 days, or within the shorter period the report specifies.

The landlord must give a copy of the report to each existing tenant within 28 days of the inspection and test, and to the local housing authority within seven days of a written request. GOV.UK's guidance adds that a new tenant must receive the report before they occupy, and that after remedial work the landlord needs written confirmation from the person who did it within 28 days of completion. The regulations were extended to the social rented sector in 2025.

One caution. GOV.UK's guidance is dated November 2025, before A4 existed. It still describes FI as further investigation required without delay and says landlords must make sure it is carried out, and it says C3 work is not required for the report to be deemed satisfactory. That guidance has not yet caught up with A4's softer FI wording, so for a rented property treat an FI conservatively and read the regulation and the report together.

Common mistakes

• Applying the pre-2026 rule that an FI makes a report Unsatisfactory to a report under A4.
• Using FI for something you could have checked within the agreed extent of the inspection.
• Recording an FI without saying what needs investigating and why you could not verify it.
• Coding a C3 as a C2 to push the customer into work, or the reverse to avoid an Unsatisfactory.
• Leaving observations without the schedule reference the form asks for.
• Telling a landlord a C3 triggers the 28-day rule. The duty applies to work the report shows is required, and C3 is an improvement recommendation.