EICR codes explained: C1, C2, C3 and FI

By Software for Tradespeople Editorial Team · Updated 12 October 2026 · Facts checked 12 Oct 2026 · 6 min read

Quick answer

EICR codes rate each fault: C1 means danger present, C2 means potentially dangerous, C3 means improvement recommended and FI means further investigation. Any C1 or C2 makes the report unsatisfactory. Under BS 7671 Amendment 4, FI alone no longer does. Landlords in England must fix C1, C2 and FI items within 28 days.

On this page

What do the EICR codes mean?
Who has to act on EICR codes?
What should I do after an unsatisfactory EICR?
How much do EICR repairs cost, and what changed in 2026?
Worked example: reading a real-world style report
What mistakes do people make with EICR codes?
Which software helps electricians code EICRs correctly?
FAQs

The codes are the part of an EICR that decides what you must fix and how fast. Here is what C1, C2, C3 and FI mean, which ones fail a report, how Amendment 4 changed FI in 2026, and the deadlines for landlords in each UK nation.

What do the EICR codes mean?

EICR observation codes and what they mean for the result (checked 12 Oct 2026)
Code	Meaning	Makes the report unsatisfactory?	Landlord action (England)
C1	Danger present. Risk of injury now	Yes	Fix within 28 days or sooner; the inspector may make it safe on the spot
C2	Potentially dangerous	Yes	Fix within 28 days or sooner
C3	Improvement recommended	No	Optional
FI	Further investigation advised: the inspector could not fully identify a possible fault	No on A4:2026 forms (Yes on older A3 forms)	Investigate within 28 days (GOV.UK guidance)

NICEIC puts it simply: any C1 or C2 makes the report unsatisfactory. If there are none, the report is satisfactory, even with a long list of C3s.

C1: danger present

The ECA's coding guidance describes C1 as a defect that presents an immediate danger of shock or fire, where a single event is enough to cause harm. Its example: an exposed live part that anyone in a home could touch. The inspector will normally make a C1 safe before leaving, for example by isolating the circuit, and may ask you to sign a danger notice.

C2: potentially dangerous

Not dangerous right now, but it would become dangerous if another fault happened or someone did something foreseeable. The ECA gives the same exposed live part as an example, but out of reach in an industrial setting used by skilled people. Common domestic C2s include missing earthing or bonding and damaged accessories.

C3: improvement recommended

The installation does not meet the current BS 7671 in that respect, but there is little or no potential for danger. Older installations built to an earlier edition will often have C3s. A C3 does not mean the work was done wrong at the time.

FI: further investigation

Used when the inspector suspects a problem but could not fully identify it within the agreed extent and limitations of the inspection. The IET points out that further investigation "may reveal a C1 or C2", which is why landlords should not ignore it.

Who has to act on EICR codes?

Private landlords everywhere in the UK must deal with C1 and C2 faults. Social landlords in England have been covered since 1 November 2025. Homeowners are not legally required to act, but a C1 or C2 is a real safety risk and worth fixing quickly. Electricians must code each observation themselves; the ECA says the inspector should be able to cite a BS 7671 regulation for every code and should not lower a code because a client asks.

Differences across the UK. England and Northern Ireland: remedial work within 28 days, or sooner if the report says. Scotland: the statutory guidance says C1 and C2 items must be fixed and FI items investigated as soon as practicable; C3s are recommendations. Wales: landlords must give the contract holder written confirmation of investigatory or remedial work within 14 days of receiving it. For the full rules in each nation, see our EICR guide.

What should I do after an unsatisfactory EICR?

Read the observations list. Each item has a code and a location. Ask the electrician to explain anything unclear.
Check any C1 was made safe. If a circuit was switched off, make sure the tenant knows and has safe alternatives.
Get a quote for the C1, C2 and FI items. Many electricians quote for repairs with the report. You can use a different registered electrician if you prefer.
Book the work inside the deadline. In England that is 28 days from the inspection, or sooner if the report says so.
Get paperwork for the repairs. The electrician should issue a Minor Works Certificate or an Electrical Installation Certificate, depending on the work. Our guide to electrical certificates explains which.
Send confirmation. In England, give the tenant and the council written confirmation within 28 days of the work being finished, with the original report.
Keep everything. Keep the EICR and repair certificates until the next inspection (six years in Scotland).

How much do EICR repairs cost, and what changed in 2026?

Repairs are priced separately from the inspection. Costs depend entirely on the fault: re-fixing a cracked socket is a quick job, while replacing an old consumer unit is a bigger one. Home Checkup's cost guide puts a consumer unit upgrade at £350 to £600. For the inspection itself, see our EICR cost guide.

Amendment 4 and FI

BS 7671:2018+A4:2026 was published on 15 April 2026, and the previous edition is withdrawn on 15 October 2026. On the new forms, NICEIC says observations are split into two parts, and FI no longer makes an installation unsatisfactory, with "without delay" removed. The IET explains that FI and C3 are now "decoupled" from C1 and C2. NICEIC is asking its contractors to tell clients about the FI change.

The catch for landlords in England: the GOV.UK guidance we checked on 12 October 2026 still lists FI alongside C1 and C2 as needing action within 28 days. Until that guidance changes, treat FI as a 28-day job.

Worked example: reading a real-world style report

A 1970s 2-bed flat gets this list of observations on an A4:2026 form:

Example observations and what they mean for a landlord in England
Observation	Code	Effect
Socket in kitchen cracked, live parts accessible	C1	Unsatisfactory; made safe on the day
No main bonding to the incoming water pipe	C2	Unsatisfactory; fix within 28 days
Bedroom sockets not RCD protected	C3	No effect on the result
Lighting circuit insulation reading low, cause not found	FI	Does not affect the result on A4 forms; investigate within 28 days under GOV.UK guidance

Result: unsatisfactory, because of the C1 and C2. If the inspection was on 1 November 2026, the socket, bonding and lighting investigation must all be done by 29 November 2026. If the investigation then finds damaged cable, the electrician records it on a new certificate. Without the C1 and C2, the same report would be satisfactory on A4 forms, even with the FI. On the old A3 forms, the FI alone would have made it unsatisfactory.

What mistakes do people make with EICR codes?

Treating C3 as a fail. It is a recommendation. Do not let anyone pressure you into urgent work on C3s alone.
Treating FI as optional. A4 softened the wording, but the GOV.UK landlord guidance has not caught up.
Over-coding. The ECA warns that overusing C1 and C2 causes unnecessary cost and disruption. A good report explains each code.
Not asking for the regulation. Every code should be tied to a BS 7671 regulation.
Losing the repair certificate. Without written confirmation, you cannot show the council the faults were fixed.

Which software helps electricians code EICRs correctly?

Good certificate software makes coding faster and more consistent. NICEIC Online includes a "Code Assist" tool for its contractors, and NAPIT FastTest (£195 ex VAT, £234 inc VAT) includes NAPIT's EICR Codebreakers guidance. Independent apps such as Tradecert and iCertifi let you save common observations and reuse them, and both support A4:2026 forms. Check that any app you use has the new two-part observations section before 15 October 2026. Our electrical certificate software comparison shows prices, devices and A4 support side by side.

Our verdict

Fix every C1 and C2 within 28 days, investigate every FI in the same window even though A4 calls it advisory, and treat C3s as a to-do list for the next time an electrician is on site. Electricians should move to A4 forms now and explain the FI change to landlord clients.

Frequently asked questions

Does a C3 fail an EICR?

No. C3 means improvement recommended. The installation does not meet the current edition of BS 7671 in that respect, but it is not considered dangerous. A report with only C3 observations is satisfactory, and landlords in England are not legally required to act on C3s, although many are worth doing during other work.

What is the difference between C1 and C2?

C1 means danger is present now: one event, such as touching an exposed live part, could cause harm. C2 means potentially dangerous: harm would need a second fault or a foreseeable action. Both make the report unsatisfactory. With a C1, the electrician will usually make the danger safe before leaving.

Does FI make an EICR unsatisfactory?

It did under the A3:2024 forms. On the A4:2026 forms, published 15 April 2026, FI is advisory and no longer makes the installation unsatisfactory on its own. However, the GOV.UK guidance for landlords in England still says further investigation must be carried out within 28 days, so landlords should act on it.

How long do I have to fix C1 and C2 faults?

Landlords in England have 28 days from the inspection, or less if the report gives a shorter time. They must then send written confirmation, such as a Minor Works Certificate, to the tenant and the council within 28 days of the work. Northern Ireland uses the same 28-day period.

Is no RCD on sockets a C2 or C3?

It depends on the circumstances, but the ECA's coding guidance notes that Electrical Safety First's Best Practice Guide 4 treats indoor sockets without RCD protection as a C3 in many cases. Sockets likely to supply equipment used outdoors are treated more seriously. The inspector decides, and must be able to cite the regulation.

Can I challenge an EICR code?

Yes. Ask the inspector which BS 7671 regulation the code is based on; the ECA says inspectors should be able to cite one and should not change codes because of client pressure. If you still disagree, get a second opinion from another registered electrician, or complain to the electrician's scheme, such as NICEIC or NAPIT.

Sources and checks

Prices, features and ratings were checked on 12 October 2026 against these sources. Software prices change often, so confirm on the vendor's site before you buy.