EICR Codes C1, C2, C3 and FI: What They Mean and What to Do

EICR codes tell you how serious each fault on an Electrical Installation Condition Report is. C1 means danger present, act immediately. C2 means potentially dangerous, fix urgently. C3 means improvement recommended, but not unsafe. FI means the electrician found a possible problem and further investigation is needed without delay. Any C1 or C2 makes the whole report unsatisfactory; C3 items alone do not.

The examples below come from Electrical Safety First's Best Practice Guide 4, which inspectors across the industry use to code domestic installations consistently. It is the same coding you will see on a report from our EICR reporting service.

C1: danger present

A C1 means someone could be hurt right now. Electrical Safety First's guidance says the inspector should tell you straight away, not wait for the written report, and with your agreement make the danger safe before leaving, for example by isolating the circuit or fitting a temporary barrier.

Typical C1 observations:

• A circuit breaker missing from the consumer unit with no blank fitted, leaving live parts exposed

• A badly damaged socket or switch with live parts you could touch

• Live conductors with missing or damaged insulation within reach

• Metalwork that has become live because of a fault

• Incorrect polarity at the origin of the installation

Even if the electrician makes it safe on the spot, the C1 still goes on the report unless the permanent repair has been done.

C2: potentially dangerous

A C2 is not dangerous today, but would become dangerous if a fault or foreseeable event happened. It needs putting right urgently. This is the code most unsatisfactory reports hinge on.

Common C2 observations in homes:

• No reliable means of earthing for the installation, or a gas or water pipe being used as the earth

• Missing main protective bonding to incoming gas and water pipes

• No RCD protection on sockets likely to power equipment outdoors

• The main RCD failing to trip when tested on an installation with its own earth rod (a TT system)

• A socket (other than a shaver socket) within 2.5 m horizontally of the boundary of zone 1 in a bathroom

• A loose connection showing signs of overheating, or scorching around equipment

• Insulation resistance below 1 megohm, or insulation so old it breaks away from the conductors

• A "borrowed neutral", where two separately protected circuits share one neutral

• Oversized fuse wire in an old rewireable fuse, so the circuit is not properly protected

C3: improvement recommended

A C3 means the installation is not unsafe, but bringing it up to date would make it safer. The IET's own Wiring Matters magazine is clear that C3 codes do not result in an unsatisfactory outcome, whatever the number of them.

Typical C3 observations:

• No RCD protection on lighting circuits in a home

• No RCD protection on cables buried less than 50 mm deep in walls

• A plastic consumer unit under a wooden staircase or in the only escape route

• No surge protection where BS 7671 would now require it

• No arc fault detection devices (AFDDs) in a house in multiple occupation

• An older Type AC RCD fitted where a Type A is now required

• Unsheathed flex used for pendant lights

Many of these reflect rules that changed after the house was wired. An installation built to an older edition of BS 7671 is not unsafe just because it does not match the current one.

FI: further investigation

FI is used when the electrician has spotted a possible safety issue but cannot give it a code without more work, often because it lies beyond the agreed extent of the inspection. Electrical Safety First's guidance expects that in most homes it should be possible to code every observation without an FI, so an FI is worth taking seriously: it needs investigating as soon as possible, and once investigated it gets a proper code. For landlords, government guidance treats an FI as needing further investigation without delay.

Which codes make an EICR unsatisfactory?

Any C1 or C2 anywhere in the report means the overall condition must be recorded as unsatisfactory. If the only observations are C3s, the overall result can be satisfactory. The IET's model report form treats FI the same way as C3 for the overall result: advisory, not a fail on its own. That does not make an FI optional, and for landlords it carries the same 28-day deadline as a C1 or C2. The recommended date for the next inspection also assumes the C1s are fixed immediately and the C2s urgently.

What happens if an EICR fails?

An unsatisfactory report is a list of jobs, not a verdict on the whole house. In most homes the C2s come down to a handful of specific items: an RCD, bonding, a damaged accessory. Occasionally the pattern of faults (perished insulation on several circuits, no earth on lighting) points to rewiring rather than repairs, and a good report explains why.

Once the remedial work is done, the electrician issues certification for it, and the installation can be retested. Keep that paperwork with the EICR: together they show every code was closed off.

The 28-day rule for landlords

Landlords in England have a legal deadline. Under the Electrical Safety Standards in the Private Rented Sector (England) Regulations 2020, which since 2025 also cover social landlords, where a report shows remedial work or further investigation is required, the landlord must have it carried out within 28 days, or sooner if the report specifies a shorter period. In practice that means every C1, C2 and FI.

The landlord must then give written confirmation from the electrician who did the work to the tenant and to the local council within 28 days of the work being completed. C3 items do not have to be done to comply. Our guide to the landlord electrical safety certificate covers the rest of the duties, and our post on how long an EICR lasts covers when the next one is due.

EICR code questions, answered

How many C3s are acceptable?

There is no limit. A report with ten C3 observations and no C1, C2 or FI is still satisfactory. It is a to-do list for when you next have work done, not a failure.

Can I argue with a code?

You can ask the electrician to explain it. Electrical Safety First's guidance says inspectors should follow its coding examples and justify any departure from them, and that the inspector's judgement should not be swayed by the person ordering the report. A second opinion from another registered electrician is reasonable if a code looks wrong.

Does a C2 mean I have to switch the circuit off?

Not usually. A C2 is potentially dangerous, not dangerous now, so the circuit can normally stay in use while the repair is arranged. A C1 is different and may mean isolating the circuit until it is fixed.

Getting the codes cleared

If you have an EICR with C1, C2 or FI observations, we can quote for the remedial work, carry it out and issue the certification you need. SM Electrical works from Shifnal across Wolverhampton, Telford and the wider West Midlands, and you can send us your report for a quote.