Short answer: C2 on an EICR means “potentially dangerous — urgent remedial action required”. It is the second-highest code (C1 is “danger present”), and a single C2 anywhere on the report makes the whole installation unsatisfactory. For a landlord that starts the 28-day clock to fix it under the 2020 Electrical Safety Regulations, with civil penalties up to £40,000 per breach since 1 May 2026. For an owner-occupier it is a strong recommendation, not a legal order. The good news: most C2s are one-visit fixes. F & A Electrical (NICEIC registered, 9.32/10 from 242 reviews) fixes C2s across North and East London from £108 labour-only and re-issues a satisfactory report. Call 07407 627542 or WhatsApp with a photo of your report and we’ll tell you what each item will cost before you book.
What “potentially dangerous” actually means
An inspector gives a C2 when a defect could cause injury or fire if something else goes wrong — a fault, a wet hand, a failed appliance — rather than being live and exposed right now (that is a C1). The test the inspector applies comes from BS 7671 and the industry guidance (Electrical Safety First’s Best Practice Guide 4): would a reasonably foreseeable event turn this into a danger? If yes, C2. If it is merely non-compliant with today’s rules but not dangerous, it is a C3 (“improvement recommended”) and does not fail the report. The C1/C2/C3 codes guide explains all four codes; this page is about the C2s you are most likely to be looking at.
The 15 most common C2s on London EICRs — and what each costs to fix
These are the C2 observations we see most often on reports in North and East London flats and houses, in rough order of frequency. Prices are labour-only from-prices, materials at trade cost, minimum charge £108 (£90 + VAT). Several items fixed on the same visit are quoted as a single job.
| # | C2 observation (as worded on the report) | Why it’s C2 | Fix | Labour from |
|---|---|---|---|---|
| 1 | No RCD protection to socket outlets / to circuits in bathroom | An RCD is what stops a shock being fatal; sockets and wet rooms without one are the classic C2 | RCBO board upgrade, or add RCD/RCBOs to existing board if space allows | £450 (board) / £180 (add RCBOs) |
| 2 | Main protective bonding to gas and/or water absent or undersized | Without bonding, a fault can make the pipework live | Run 10mm² bonding to gas meter and water stopcock | £140 |
| 3 | No supplementary bonding in bathroom (and no RCD) | Only a C2 when RCD protection is also missing; with RCDs it drops to C3 | Usually resolved by item 1 (adding RCD protection) | included in item 1 |
| 4 | Earthing conductor undersized / main earth missing or not verified | Nothing else protects you if the earth path is inadequate | New 16mm² earthing conductor to the supplier’s earth terminal, or DNO call to provide an earth | £140 |
| 5 | Damaged or broken socket / switch / light fitting exposing live parts | Live parts accessible once the crack widens | Replace accessory | £108 |
| 6 | Consumer unit of combustible (plastic) construction with signs of thermal damage | Plastic boards alone are C3; scorch marks or heat damage make it C2 | Replace with metal RCBO board | £450 |
| 7 | Loose connections / signs of overheating at consumer unit | Arcing at a loose terminal is a fire source | Strip, clean, re-terminate and torque every connection | £108 |
| 8 | Ring final circuit continuity fault (open ring / “broken ring”) | Half the ring carries the full load on cable rated for half | Trace the break, repair the joint or replace the leg | £140 |
| 9 | Low insulation resistance on a circuit (below 1 MΩ) | Cable insulation breaking down; leakage and fire risk | Locate the damaged section, replace or rewire the circuit | £180 (fault-find + repair); full circuit rewire quoted |
| 10 | Earth fault loop impedance (Zs) too high for the protective device | The breaker won’t trip fast enough under fault | Improve earth path, or fit RCBO to the circuit | £108–£140 |
| 11 | Borrowed neutral / shared neutral between circuits (usually lighting) | A circuit can stay live with its own breaker off — dangerous to anyone working on it | Separate the neutrals at the boards and switches | £140 |
| 12 | Unenclosed / exposed connections (chocolate-block joints in loft, under floor, behind appliances) | Live terminals reachable by hand or by vermin | Re-make in maintenance-free junction boxes | £108 |
| 13 | Cables not adequately supported / running through heat or damage zones | Mechanical damage exposes conductors over time | Re-route, clip and sleeve | £108 |
| 14 | Incorrect polarity at a socket or lighting point | Switches break the neutral — the fitting stays live “off” | Correct the connections; retest polarity on the circuit | £108 |
| 15 | Sockets or switches within reach of a bath or shower (Zone 1/2) | Shock risk with wet hands | Remove and blank, or relocate outside the zone | £108 |
Two things worth knowing. First, items 1–4 are the ones that turn up on almost every 1960s–1990s London installation that hasn’t been touched since — so a “failed” EICR on an older flat is usually a bonding-and-RCD story, not a rewire story. Second, a board upgrade clears several C2s at once (1, 3, 6, 7, often 10) and is frequently the cheapest route to a satisfactory report, which is why our fuse board replacement price is labour-only £450 including certificate. The full remedial pricing method is on the EICR remedial work cost guide.
Is a C2 ever wrong?
Yes, and it matters because a C2 costs you money. The commonest over-coding we see on other firms’ reports: a plastic consumer unit with no thermal damage coded C2 (should be C3); missing supplementary bonding in a bathroom that does have RCD protection (C3); absence of RCD on a lighting circuit only (C3 in most cases); and “no surge protection” coded as anything other than C3. Some cheap-EICR operators code aggressively to sell the remedials. If your report has more than four or five C2s on a flat that has been fine for years, a second-opinion EICR (£140) that re-codes every observation against BS 7671 is often cheaper than the remedials — and gives you a written report to send back. What happens after a fail, including the 28-day landlord clock, is on what happens when an EICR is unsatisfactory.
What a C2 means for landlords specifically
Under the Electrical Safety Standards in the Private Rented Sector (England) Regulations 2020, an unsatisfactory report (any C1, C2 or FI) means you must complete the remedial work within 28 days — or sooner if the report says so — using a qualified person, then give the tenant and, if asked, the council written confirmation within 28 days of the work being done. Since 1 May 2026 the Renters’ Rights Act raised civil penalties to up to £40,000 per breach, and councils in Hackney, Haringey, Tower Hamlets and Newham enforce actively through licensing. The full duty list is on the landlord EICR page. If your flat is leasehold and the C2 sits on the landlord’s supply (missing main earth from the block, for example), the leasehold flat EICR guide explains whose cost it is.
What happens after the fix
Once the C2s are cleared we issue either a Minor Works or an Electrical Installation Certificate for the remedial work, and — where the fix changes the outcome of the original inspection — an updated EICR marked satisfactory. Many landlords are surprised to learn that a satisfactory EICR does not require every C3 to be fixed: only C1, C2 and FI items fail a report. We list the C3s with prices anyway so you can decide. Same-day remedials and re-tests are usually possible when a tenancy start or licence deadline is close.
Frequently asked questions
Does one C2 fail an EICR?
Yes. A single C1, C2 or FI (further investigation) anywhere on the report makes the overall assessment unsatisfactory. C3 items never fail a report on their own.
How quickly must a C2 be fixed?
Landlords: within 28 days of the report (or the shorter period the report specifies). Owner-occupiers: no legal deadline, but “potentially dangerous” means it should not wait for the next inspection.
How much does it cost to fix C2s on an EICR in London?
Single items from £108 labour-only; bonding £140; adding RCD protection £180; full consumer unit replacement £450. A typical 1970s flat with the classic bonding + RCD C2s is £450–£600 labour all-in, including the satisfactory re-test.
Do I need a new EICR after the C2s are fixed?
Not always. The remedial certificate plus the original report is accepted by most councils and agents as evidence. Where the fix changes the original assessment, or the agent insists, we issue an updated satisfactory EICR — from £108 as a re-test on the same installation.
What’s the difference between C2 and FI?
FI means the inspector could not reach a conclusion — for example a circuit that could not be isolated for testing. It also fails the report, and the fix is to investigate (from £108) and then either clear it or code what is found.
Can a plastic fuse board be a C2?
Only if there is evidence of thermal damage, loose connections or missing blanks. An intact plastic board in a domestic setting is C3 under current guidance.
Related: C1, C2, C3 and FI explained, remedial work costs, EICR cost London 2026, EICR testing London, all service areas.