EICR codes explained: C1, C2, C3 and FI for contractors
An EICR's outcome turns on four codes. Here is what each means, what Amendment 4 changed in 2026, how often commercial buildings need inspecting, and how to turn the observations into remedial work.
An Electrical Installation Condition Report (EICR) records the condition of an existing installation against BS 7671. Most of it is a schedule of inspections and test results, but the part the client reads is the list of observations, each with a classification code, and the overall assessment: satisfactory or unsatisfactory.
For a contractor, the codes matter twice: they decide whether the report is satisfactory, and they are the remedial work the inspection has found.
The four codes
| Code | Meaning | Outcome | What normally follows |
|---|---|---|---|
| C1 | Danger present. Risk of injury. Immediate remedial action required. | Unsatisfactory | Made safe on the day (isolated or fixed), the client told before you leave |
| C2 | Potentially dangerous. Urgent remedial action required. | Unsatisfactory | A remedial quote, as soon as possible |
| C3 | Improvement recommended. | Does not affect the outcome | Optional work; quote if the client wants it |
| FI | Further investigation is advised. | Does not affect the outcome (since Amendment 4) | A price to investigate, which may turn up a C1 or C2 |
What Amendment 4 changed
BS 7671:2018+A4:2026 changed how FI works. Before, FI meant "further investigation required without delay", and in practice many inspectors treated an FI like a C2, marking the report unsatisfactory. Amendment 4 decouples C3 and FI from C1 and C2: only C1 and C2 make a report unsatisfactory, and FI now reads "further investigation is advised". The IET's own commentary adds that it should not be necessary to use FI in most circumstances.
Satisfactory or unsatisfactory
The overall assessment is unsatisfactory if there is any C1 or C2 observation. It stays unsatisfactory until the remedial work is done; the inspector does not change the original report. Most contractors issue a minor works or electrical installation certificate for the remedial work, and the client keeps it with the EICR as proof the observations were dealt with.
A report with C3s only is satisfactory. C3s are worth raising with the client anyway: they are often the next round of work, and a client who is told about them now trusts the next quote more.
How often commercial buildings need an EICR
There is no single legal interval for commercial premises. The Electricity at Work Regulations 1989 require installations to be maintained so as to prevent danger, and the usual benchmark is the maximum periods recommended in the IET's Guidance Note 3:
| Premises | Maximum period between inspections |
|---|---|
| Offices, shops and other commercial premises | 5 years |
| Schools and other educational establishments | 5 years |
| Hospitals | 5 years |
| Industrial premises | 3 years |
| Leisure complexes and places of public entertainment | Shorter, typically every year |
Turning codes into work
The commercial risk in an EICR is not the inspection; it is the C2 that sits in a PDF for three months because nobody turned it into a quote. A few habits fix most of it:
- Quote every C2 within a week. The client needs it fixed to make the installation satisfactory, and the longer it waits the more likely someone else quotes it.
- Price FIs as investigation, not as fixes. The FI says you don't yet know what's wrong. Quote the time to find out, and the fix separately once you do.
- Group observations by site. One quote per site with every C2 and FI on it is easier for the client to approve than six separate ones.
- Offer the C3s, separately. Don't bury optional work in the urgent quote; it slows the approval of both.
- Diarise the next inspection. Put the next due date on the site with a reminder, so the re-inspection is yours, not the next contractor's.
How PPMdesk handles it
PPMdesk does not produce the EICR itself; your engineers keep using their certification software. Around it: an EICR visit sheet records the outcome and the number of C1s, C2s, C3s and FIs, and the engineer reports each C2 or FI from the job on their phone, with photos and a price, and they arrive in Faults found by site. Tick them and they become one quote at cost plus your markup, which the client accepts online with their PO. The finished EICR PDF is filed on the site with its next due date, and shows on Today's list 30 days before it is due. How PPMdesk works for electrical contractors.
Frequently asked questions
Does an FI code make an EICR unsatisfactory?
Not since BS 7671:2018+A4:2026. Amendment 4 decoupled FI and C3 from C1 and C2, so only C1 and C2 observations make a report unsatisfactory. Under earlier editions, an FI usually did.
What is the difference between C1 and C2?
C1 means danger is present now and needs immediate action, so the inspector makes it safe or isolates it before leaving. C2 means potentially dangerous: not a danger yet, but it could become one, so it needs urgent remedial work.
Is a C3 a fail?
No. C3 means improvement recommended. A report with only C3 observations is satisfactory.
How often does an office need an EICR?
IET Guidance Note 3 recommends a maximum of five years for commercial premises such as offices and shops. The inspector may recommend a shorter interval on the report, and that recommendation is the one to follow.
- IET Wiring Matters 110 (July 2026): Further investigation
- Electrical Safety First: best practice guides (including BPG4 on classification codes)
- Periodic inspection intervals (IET Guidance Note 3 table), TLC Direct
Checked on 5 November 2026. If anything here is out of date, tell us and we will correct it.
