EICR codes explained: C1, C2, C3 and FI, with a code checker
An EICR classifies each observation as C1 (danger present), C2 (potentially dangerous), C3 (improvement recommended) or FI (further investigation required). Any C1, C2 or FI makes the report unsatisfactory; a report whose only observations are C3s is satisfactory.
Type what you found: "no RCD on sockets", "cracked socket", "borrowed neutral". The usual code, the regulation it breaks and the notes on when it changes come up as you type.
The classification codes of the BS 7671 model Electrical Installation Condition Report, and Pascal's own library of common observations. Checked against BS 7671:2018+A4:2026, updated 3 September 2026. Free, and nothing to sign in to.
- C1
Danger present. Somebody could be hurt as things stand, so make it safe now.
Makes the report unsatisfactory
- C2
Potentially dangerous. Somebody could be hurt if conditions change, so put it right without delay.
Makes the report unsatisfactory
- C3
Improvement recommended. Nothing dangerous; the installation would be better for the change.
Report stays satisfactory
- FI
Further investigation. It could not be judged within the extent of this inspection.
Makes the report unsatisfactory
What do the EICR codes mean, and where does the library come from?
An Electrical Installation Condition Report classifies every observation with one of four codes, and the codes decide the report's overall assessment. C1, danger present, and C2, potentially dangerous, each make the installation unsatisfactory, as does FI, further investigation required. C3, improvement recommended, does not: a report whose only findings are C3s is satisfactory, and the improvements are advice rather than a requirement.
The code is a judgement about the danger presented by the installation in front of the inspector, not a lookup against a list. The same missing RCD is a different finding on a socket that only ever feeds a lamp and on the one the lawnmower runs off. That is why the library gives the usual code and, where it matters, says what the answer turns on.
The library
About three hundred common findings, written by us in plain English with the regulation each cites and the item on the schedule of inspections it belongs to. It is the same library that suggests the wording, code and regulation as an observation is typed into a Pascal EICR. Search it by what you found: the room, the accessory, the fault, trade slang included, or by a regulation number.
Worked example
Three findings on one report, and what the codes make of them.
- Exposed live conductor at a damaged pendant: C1. Somebody could touch it now. Make it safe before leaving, and the report is unsatisfactory.
- No RCD protection on the socket circuits: C2 in most dwellings, because a socket may feed equipment used outdoors. Unsatisfactory, to be put right without delay.
- Old wiring colours with no warning notice at the board: C3. Nothing dangerous; a label would improve it. On its own the report would still be satisfactory.
Type any of those three into the box above and the library gives the code, the regulation and the note on when it changes.
Questions the trade asks
C1 is danger present: somebody could be hurt as things stand, make it safe now. C2 is potentially dangerous: somebody could be hurt if conditions change, put it right without delay. C3 is improvement recommended: nothing dangerous, but the installation would be better for the change. FI is further investigation: it could not be judged within the extent of this inspection.
Any C1, any C2, or any FI. A report whose only observations are C3s is satisfactory, because the improvements are recommended, not required.
Because the code is a judgement about danger in the installation in front of them, not a lookup. A missing RCD on a socket that only ever feeds a lamp is not the same finding as one on the socket the lawnmower runs off. The library suggests the usual code and says, where it matters, what the answer turns on.
Yes. C3 means improvement recommended, and the assessment stays satisfactory. It still belongs on the report: the client is entitled to know what would make the installation better, and the next inspector is entitled to see it was noticed.
It is Pascal's own library of about three hundred common findings, written by us in plain English, each with the usual code and the regulation it cites. The same library suggests the wording, code and regulation as you type an observation into a Pascal EICR. It is a starting point for your judgement, not a substitute for it.
Next door
- Max Zs calculator: maximum Zs for MCBs, RCBOs and fusesMaximum earth fault loop impedance for any MCB, RCBO or fuse to BS 7671, with the 80% figure a site reading is judged against. Free, no sign-up.
- Ring final circuit test calculator: r1, rn, r2 and (r1+r2)/4Check r1, rn and r2 on a ring final circuit, get the (r1+r2)/4 figure every socket should read, and the R1+R2 to record. Free, no sign-up.
The figures go straight onto the certificate
In Pascal the maximum Zs is filled in for every circuit as you pick the device, the schedule of test results carries all 32 columns, and the observation library suggests the wording, code and regulation as you type. EICs, EICRs and minor works, from £25 a month.
See the certificate softwareA calculator applies a method to the numbers you give it. It does not know the installation in front of you, and it is no substitute for BS 7671, the guidance or the judgement of the person signing the certificate. Check anything you rely on.