Quick answer
An EICR uses four codes: C1 (danger present), C2 (potentially dangerous), C3 (improvement recommended) and FI (further investigation required). Any C1, C2 or FI makes the overall report unsatisfactory. C3 items on their own do not.
| Code | Meaning | Report outcome | What happens |
|---|---|---|---|
| C1 | Danger present | Unsatisfactory | Made safe on the spot before we leave |
| C2 | Potentially dangerous | Unsatisfactory | Must be fixed. Landlords have 28 days |
| C3 | Improvement recommended | Does not fail | Advisory. Fix when convenient |
| FI | Further investigation | Unsatisfactory | Must be investigated, then coded |
C1: danger present
A C1 means someone could be injured right now. The inspector must make it safe immediately, usually by isolating the circuit or removing the damaged item, and record what was done.
Typical C1s:
- exposed live conductors, such as a broken socket or a missing cover on the consumer unit
- a live metal part that should be earthed
- signs of burning or arcing at a connection
C2: potentially dangerous
A C2 isn't immediately dangerous but could become so, for example if a fault developed or someone touched the wrong thing. It must be fixed to make the installation satisfactory.
Typical C2s:
- no RCD protection for socket outlets that could be used outdoors, or for cables buried in walls where RCD protection is needed
- a lighting circuit without a protective (earth) conductor, feeding metal fittings or switches
- missing main protective bonding to incoming gas or water pipes
- an earth fault loop impedance too high for the protective device to disconnect in time
- a consumer unit with a damaged enclosure or missing blanks
C3: improvement recommended
A C3 marks something that doesn't meet the current version of BS 7671 but isn't unsafe. It doesn't make the report unsatisfactory, and landlords don't legally have to fix it, although it is often sensible to do it while an electrician is on site.
Typical C3s:
- no RCD protection on a lighting circuit in an otherwise sound installation
- an older consumer unit that met the rules when it was installed
- no surge protection where it would now be recommended
- accessories that are worn but intact
FI: further investigation
FI means the inspector found something that couldn't be fully assessed during the inspection, such as a circuit that couldn't be traced or a test result pointing to a hidden fault. It makes the report unsatisfactory until the investigation is done and the item is re-coded.
Who decides the code?
The inspector, based on what they find and the guidance in BS 7671 and industry best-practice guides. Two inspectors can occasionally code the same thing differently. That is why the report must describe each observation clearly, and why it matters that the person signing is properly qualified (see the 2026 changes).
What to do next
If your report has C1, C2 or FI items, get a quote for remedial work. We include a fixed-price quote with every EICR we carry out. Once the work is done, you need written confirmation that the installation is now satisfactory, not normally a whole new EICR.