C1, C2, C3 and FI — What Your EICR Codes Actually Mean
An unsatisfactory report is not a disaster, and a C3 is not a fault. The codes are simpler than they look.
Most people meet these four codes for the first time on a report telling them their property is unsatisfactory, which is a bad moment to be learning terminology.
C1 — Danger Present
Something on the installation could cause injury now. Exposed live parts, for example. A C1 must be made safe on the day it is found, and any inspector who leaves without addressing it has not done their job. In practice we isolate it before we finish writing up.
C2 — Potentially Dangerous
The condition is not dangerous today but would become so under a fault. Missing earthing to a metal accessory is the classic example. A C2 makes a report unsatisfactory and must be remedied before it can be reissued as satisfactory.
C3 — Improvement Recommended
The installation is safe and complies with the standard it was built to, but would not meet current regulations. A consumer unit without RCD protection often lands here. A C3 does not make a report unsatisfactory and you are not obliged to act on it. Plenty of landlords are told otherwise.
FI — Further Investigation
The inspector could not determine whether something is safe without more work — usually because a circuit could not be traced or accessed. FI also makes a report unsatisfactory, which is why a thorough inspection is worth more than a fast one.
The Practical Upshot
Only C1, C2 and FI require action. If your report is unsatisfactory purely on C3s, something has gone wrong, and it is worth asking why.