EICR Code FI: Further Investigation
FI is the code you reach for when something on an installation looks like it could be dangerous but you couldn’t confirm it on the day — it means further investigation is required, and it makes the report unsatisfactory.
On an Electrical Installation Condition Report, most observations get a C1, C2 or C3. FI — further investigation required without delay — is different: it isn’t a verdict on how dangerous something is, it’s an admission that you couldn’t reach a verdict and someone needs to dig deeper before the installation can be signed off as safe.
This guide explains what FI means, why a single FI makes the overall report unsatisfactory, the situations that call for it, and how it differs from the classification codes C1, C2 and C3.
Key takeaways
- FI means "further investigation required without delay" — not a danger rating, but a flag that more work is needed.
- Like a C1 or C2, a single FI makes the overall EICR outcome unsatisfactory.
- Use FI when something may reveal a C1 or C2 but you couldn’t confirm it during the inspection.
- FI is about uncertainty; C1, C2 and C3 are about a defect you have already identified and assessed.
- The investigation must happen without delay, because it could uncover a real danger.
What FI means
FI stands for "further investigation required without delay." It is applied when the inspection reveals something that could be a safety concern, but the extent or seriousness cannot be established within the scope of the condition report itself. In other words, you have spotted a warning sign but you can’t yet code the underlying issue as C1, C2 or C3 because you don’t know what it really is.
The key phrase is "without delay." FI is not a note to look at it sometime; it signals that whatever you’ve found might reveal a danger, so it needs investigating promptly. Until that investigation is done, the true condition of that part of the installation is unknown.
FI is about what you don’t know yet
A classification code answers "how bad is this defect?" FI answers "I can’t tell how bad this is from here — find out." That uncertainty is exactly why it can’t be left.
Why FI makes the report unsatisfactory
An EICR is reported as either satisfactory or unsatisfactory. A single FI, like a single C1 or C2, drives the overall outcome to unsatisfactory. The logic is straightforward: if there is something on the installation that might turn out to be dangerous, you cannot honestly declare the installation satisfactory while that question is open.
Only observations coded C3 (improvement recommended) leave a report satisfactory. The moment you have a C1, a C2 or an FI on the report, the installation as a whole cannot be signed off as satisfactory — the FI has to be resolved, and any danger it uncovers dealt with, before that changes.
When to use FI
FI belongs to situations where you have a genuine reason to suspect a fault that could be a C1 or C2, but you can’t confirm it on the day. Perhaps a circuit’s behaviour is inconsistent, an accessory shows signs of heat but the cause isn’t visible without dismantling, or a reading is borderline and you suspect a problem you can’t chase down within the inspection’s scope.
It is not a substitute for doing the testing you can do. If you can establish the defect, code it — don’t hide behind FI. FI is reserved for the cases where establishing the truth genuinely needs more work than a condition report allows: more extensive testing, dismantling, or investigation of concealed parts of the installation.
Coding on TradePlanr
TradePlanr lets you assign C1, C2, C3 or FI to each observation as you inspect and issue the EICR PDF on site — so an FI is recorded clearly against the item it belongs to, with the reason attached.
How FI differs from C1, C2 and C3
The classification codes describe defects you have already identified and judged. C1 is "danger present" — a risk of injury exists now. C2 is "potentially dangerous" — safe at the moment but one fault away from danger. C3 is "improvement recommended" — not a danger, but the installation falls short of current standards in a way worth noting.
FI sits outside that scale because it isn’t a judgement about a known defect at all. It says the inspector has found something that warrants investigation before its true seriousness can be classified. An FI might, once investigated, turn into a C1, a C2, a C3 or nothing at all — but you can’t assign that code until you know, which is the whole point of the flag.
Frequently asked questions
Does an FI fail an EICR?
Yes. A single FI makes the overall condition of the installation unsatisfactory, in the same way a C1 or C2 does. Only reports carrying nothing worse than C3 observations remain satisfactory.
What’s the difference between FI and C2?
C2 is a judgement about a defect you have identified and assessed as potentially dangerous. FI means you have found something that might be a C1 or C2 but couldn’t confirm it on the day, so it needs investigating before it can be classified.
How quickly must an FI be investigated?
Without delay. The whole reason for coding it FI is that it could reveal a danger, so the further investigation should be carried out promptly rather than deferred.
From guidance to action
Related guides
EICR Code C1: Danger Present
What a C1 means, real-world examples, and the immediate action required before you leave site.
EICR Code C2: Potentially Dangerous
When to code C2, how it differs from C1 and C3, and why it makes an EICR unsatisfactory.
EICR Limitations Explained
Agreed vs operational limitations, the extent-of-inspection box, and how to record limitations properly.
