EICR Code C3: Improvement Recommended
C3 means improvement recommended: the item is not dangerous and does not need remedial action, but it falls short of the current edition of BS 7671 and would be better brought up to standard.
Code C3 is the least serious observation on an EICR, and the only one that does not make a report unsatisfactory on its own. It flags something that is safe but not ideal — usually a departure from the current wiring regulations on an older installation that was compliant when it was built.
This guide explains what C3 means, why it exists, the kinds of item that warrant it, and the common trap of using it to soften a defect that is really a C2.
Key takeaways
- C3 means "improvement recommended" — not dangerous, no remedial action strictly required.
- A report carrying only C3 observations is still classified satisfactory.
- C3 typically covers departures from the current edition on installations that were compliant when built.
- It is not a device for downgrading a genuine C2 to keep a report looking clean.
- Common C3s include no RCD on circuits not requiring it retrospectively, and no circuit labelling.
What a C3 means
Code C3 is defined in IET Guidance Note 3 as "Improvement recommended." The item is safe and does not require remedial action, but it does not meet the current edition of BS 7671. It exists because an EICR is assessed against the standard in force now, while installations are built to the standard in force at the time — so a perfectly safe older installation will legitimately pick up C3s where the regulations have since moved on.
Because a C3 is not dangerous, it never obliges the client to act. It is advice: an improvement that would bring the installation closer to current practice, offered so the client can make an informed decision.
The test for a C3
Ask: is this safe under any single foreseeable fault, but simply below today's standard? If yes, it's a C3. If a fault would make it dangerous, it's a C2.
Why C3 doesn't fail the report
The overall assessment on an EICR is satisfactory or unsatisfactory. A single C1 or C2 forces unsatisfactory; C3 observations do not. That is deliberate — it would be unreasonable to declare every older installation unsatisfactory simply for pre-dating the latest edition, when nothing about it is actually unsafe.
So a report can carry any number of C3s and still be satisfactory. The C3 list becomes the recommendations section: worthwhile improvements the client can weigh up, price up, and schedule at their own pace.
Real-world C3 examples
Common C3 items include: no RCD protection on a circuit that does not require it retrospectively but would benefit from it; the absence of circuit identification or a distribution board schedule; a lack of an RCD test notice; older but sound cable colours without a warning notice at the board; and an accessory that is functional and safe but no longer to the current standard.
The thread running through these is that none of them exposes anyone to danger under a foreseeable fault — they are shortfalls against current best practice, not safety defects.
The C2-in-disguise trap
The most common EICR error is coding a real C2 as a C3 to keep a report satisfactory — often under pressure from a client or agent who wants a clean pass. Absent bonding, a missing CPC or an out-of-limit Zs are potentially dangerous, and they are C2s regardless of how inconvenient the outcome is.
The test never changes: if a single foreseeable fault would put someone at risk, it is a C2. Only when the item is genuinely safe under any such fault, and merely below current standard, is it a C3. Getting this right protects both the occupant and you.
Keep the coding honest
TradePlanr keeps the C1/C2/C3/FI coding and the overall outcome linked, so a mis-downgraded defect can't quietly turn an unsatisfactory report satisfactory.
Frequently asked questions
Does a C3 fail an EICR?
No. A report carrying only C3 observations is still satisfactory. Only a C1 or a C2 makes the overall outcome unsatisfactory.
Do I have to fix a C3?
No. A C3 is improvement recommended, not required. It's advice the client can choose to act on. Nothing about a C3 is dangerous under a foreseeable fault.
Is no RCD always a C3?
No. Where RCD protection is now required and absent, that is normally a C2. C3 only applies where RCD protection isn't required retrospectively but would be a worthwhile improvement — the two must not be confused.
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.
Initial Verification: The BS 7671 Testing Sequence
The correct dead-then-live testing sequence for initial verification, step by step.
