EICR Code C2: Potentially Dangerous
C2 means the installation is potentially dangerous: it isn't a live danger right now, but it will become one if a further fault develops or someone contacts a part that shouldn't be reachable.
On an Electrical Installation Condition Report, Code C2 sits between the immediate danger of a C1 and the cosmetic shortfall of a C3. It is the code you reach for most often, and the one most likely to be argued over, because it hinges on a judgement about what could happen rather than what already has.
This guide sets out exactly what C2 means to BS 7671 and IET Guidance Note 3, the kinds of defect that warrant it, how it differs from C1 and C3, and how it drives the overall satisfactory or unsatisfactory outcome of the report.
Key takeaways
- C2 means "potentially dangerous" — a defect that becomes dangerous only if a further fault or event occurs.
- Like a C1, a single C2 makes the overall EICR outcome unsatisfactory.
- C2 does not require making safe on the spot, but the client must be advised remedial work is needed urgently.
- Typical C2s include no RCD protection where now required, missing or undersized bonding, and no earth at socket-outlets.
- The key test is whether a single foreseeable fault would expose someone to danger.
What a C2 means
Code C2 is defined in IET Guidance Note 3 as "Potentially dangerous — urgent remedial action required." The condition is not dangerous at the moment of inspection, but a single further fault, failure or foreseeable event would make it so. The classic case is a fault on a metal-cased appliance where the earthing is defective: no danger until the appliance develops a fault, but then the casing goes live with no path to trip the protection.
Because the danger depends on a second event, you are not expected to isolate a C2 on the spot the way you would a C1. But it is still serious: the client must be told, in clear terms, that urgent remedial work is needed, and the report cannot be signed off as satisfactory.
The test for a C2
Ask: is this safe right now, but one foreseeable fault away from injuring someone? If yes, it's a C2. If it's dangerous already, it's a C1.
C2 vs C1 vs C3
The distinction is timing. A C1 is dangerous now — exposed live parts, live conductive casings. A C2 is safe now but becomes dangerous if a further fault develops — a defective CPC, an absent RCD, undersized bonding. A C3 is not dangerous under any single fault; it simply falls short of the current edition of BS 7671.
The consequence for the report is significant: both C1 and C2 make the overall assessment unsatisfactory, whereas a report carrying only C3 observations remains satisfactory. Miscoding a genuine C2 down to a C3 to keep a report satisfactory is a serious error — it leaves a real risk unaddressed and misrepresents the installation.
Real-world C2 examples
Common conditions that warrant a C2 include: no or ineffective RCD protection for socket-outlets or circuits where BS 7671 now requires it; absent, disconnected or undersized main protective bonding to gas and water; no earthing at a socket-outlet or lighting point; an absent or broken circuit protective conductor; and a Zs too high to guarantee disconnection within the required time.
Others include damaged insulation that isn't yet exposing live parts, an accessory with signs of overheating that isn't yet dangerous, and a lack of earthing to exposed-conductive-parts of Class I equipment. In each case the installation works and looks fine until a fault arrives — at which point there is no protection.
How to record and act on a C2
Describe the defect precisely, classify it C2, and mark the overall assessment unsatisfactory. Unlike a C1 there is no expectation to make safe before leaving, but you must make sure the client understands the word "urgent" is not decoration — the remedial work should be carried out promptly, and you should say so on the report and in conversation.
Where a C2 could be argued either way against a C1, err towards the more serious code if there is any real, present risk. Where it could be argued against a C3, remember the test: if a single foreseeable fault puts someone at risk, it is a C2, not an improvement recommendation.
Code it on site
TradePlanr lets you code every observation C1, C2, C3 or FI as you go, so the overall outcome and the remedial list write themselves — and the client gets a proper PDF before you leave.
Frequently asked questions
Does a C2 fail an EICR?
Yes. A single C2 (like a C1) means the overall condition of the installation is reported as unsatisfactory. Only reports carrying nothing worse than C3 observations remain satisfactory.
Do I have to make a C2 safe on site?
No — unlike a C1, a C2 is not an immediate danger, so there is no expectation to isolate it before leaving. But you must advise the client that urgent remedial work is required and record that clearly.
Is no RCD protection a C1, C2 or C3?
Where RCD protection is now required (for example on socket-outlets in most premises) and it's absent, that is normally a C2 — potentially dangerous — because a fault or contact with a live part would go uninterrupted. It is not usually a C1 unless there is also a present danger.
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 C3: Improvement Recommended
What C3 covers, why it does not fail an EICR, and common examples you can code C3.
RCD Keeps Tripping: Causes and Fixes
A structured method for tracing why an RCD trips — from nuisance tripping to real faults.
