EICR Codes

Does the report pass?

BS 7671:2018+A4:2026 (the default here, and required for EICRs from 15 October 2026):

• Unsatisfactory: any C1 or C2.
• Satisfactory: only C3 and/or FI (advisory), and limitations.

The book and Amendment 3: any C1, C2 or FI is unsatisfactory; only C3s and limitations pass. Switch in Tools → Settings.

The client decides whether to fix C3s. Depending on the building, they may still have a duty of care. For rented homes, see Tools → Rented-home rules. Details of what changed: Tools → Changes since the book.

Each book entry gives (1) wording for the EICR, (2) the regulation it may breach (BS 7671 number, or ESQCR for supplier equipment) and (3) a suggested code.

If your fault isn't listed, find the closest example and follow its logic. Not being listed doesn't mean you can ignore it.

Agree limitations with the client before you start, and record them (and who agreed) in section D, "Extent and Limitations". Always safely isolate before removing covers.

• Tell the client straight away. Don't wait for the report.
• You may halt the inspection and carry on only once it's made safe, isolated or repaired. You have a duty of care to yourself and others.
• The NAPIT Dangerous Situation Report records that the client was told, and whether they gave permission to make it safe. If they refuse, they accept responsibility.

C2 and FI

You needn't tell the client until the inspection is finished and the report is issued. How urgent the repair is, is the client's decision.

These fall under the ESQCR, not BS 7671. Supplier remedial work is almost always free. The client chooses whether to call. If you call for them, that's on top of the EICR.

Urgency

C1: raise immediately where practicable. C2 or FI: as a matter of urgency. C3: client's choice.

Have ready before you call

1. Your name and number (if acting for the client)
2. Client's name and number
3. The most serious issue
4. Secondary issues, plus use of the installation and any access or environment problems
5. Address and postcode
6. MPAN (on the electricity bill or the meter)

Finding the DNO

The MPAN identifies it, or use the Energy Networks Association's postcode checker. Meter operators are usually named on the bill.

Supplier "emergency codes" include

• Burning, smell of smoke or smoke
• Exposed live conductors
• Cut-out running hot
• Physical damage needing immediate action
• Arcing sounds
• Broken fuse carrier exposing live parts
• Earthing issues that are an immediate risk

Rules

• One code per MPAN, most serious first.
• Report everything in one go. Don't drip-feed.
• Keep the reference number they give you.
• Make sure any C1 is properly resolved.

• First inspection: set under Reg 644.4, based on the use and who is responsible for the installation.
• Later inspections: Reg 653.4 says you must explain your recommended interval.
• The client (or responsible person) is the only one responsible for ongoing electrical safety. They know how the installation is really used and should supply the risk assessment behind their interval. The contractor isn't responsible for the interval.
• If the client gives documented evidence for a shorter or longer interval, you can adopt it by attaching their evidence to your report.
• Private rented homes have legal maximum intervals in Scotland and Wales, and England is following. Check the government site for the current rule.

Risk bands (Tools tab has a score calculator)

Likelihood factor and interval (book Table 3.1)

For landlords and others who find risk assessment daunting

Two simpler routes: a table of fixed frequencies (restrictive, but cautious when you know little about the installation) or a simplified sliding scale (the book's preferred, semi-risk-assessed route) that offers three possible frequencies depending on what you find and what the client can keep in place. Both need extra care where the installation is in poor repair.

The book includes full risk-assessment forms in Part 2 (book pages 62–81).

A limitation is a check or test you don't do, agreed with the client beforehand. It doesn't affect pass or fail.

• Agreed: set with the client before starting.
• Operational: site problems you hit. Raise them with the client straight away.

Don't overuse them. Too many weakens the report, and an investigator may apportion blame if something goes wrong in an area you limited.

Examples: sampling, locations (such as Part 7 areas needing a specialist), level of visual inspection, which tests are done.

Social housing: keep these running

Life-sustaining equipment, fire alarms and sprinklers, emergency lighting, warden call, induction loops, stairlifts and mobility access equipment.

A Routine Operational Visual Inspection (Electrical) between EICRs:

• Meter bypass or tampering
• Obvious damage to accessories
• Main earth conductor in place
• Protective bonding conductors in place
• RCDs and RCBOs trip on the test button
• Other safety devices operate on their test button

Tenants who have made unsafe, unregistered or non-compliant changes, or tampered with the supply, justify shorter inspection intervals.

A 30 mA RCD is required for socket-outlets up to 32 A and for mobile equipment up to 32 A used outdoors.

• Dwellings: mandatory. No risk assessment can remove it.
• Other premises: a documented risk assessment may show an RCD isn't needed.
• Cost or budget is never a valid reason.
• The 18th Edition no longer allows a labelled socket for one specific piece of equipment as a way round it.
• The client or duty-holder owns the assessment and any liability, even if a contractor helps. If they omit the RCD, the assessment must be attached to the EICR.

What to do when you find sockets with no RCD (non-dwelling)

1. C2: you've confirmed there's no suitable risk assessment.
2. FI: an assessment may exist and the client is looking for it (advisory under A4).
3. Agreed in limitations: the client assesses the risk. The outcome is either no code (satisfactory) or a C2 for them to address.

How the assessment works

Score likelihood (1–5) against severity (1–5). Multiply for a score, then match it to the bands (Tools tab). Likelihood draws on incident history, equipment type, environment and maintenance. Severity ranges from "no illness or lost time" up to a RIDDOR incident involving death or major injury.

Control measures can include procedures, physical barriers, specified equipment types, safe systems of work, training, supervision and PPE. The assessment should be reviewed periodically.

Max Zs = a constant ÷ the device rating. The 80% figure uses a lower constant. Use the Zs calculator in the Tools tab.

Example: Type B, 32 A → 43.7 ÷ 32 = 1.37 Ω (100%).

• For BS EN 60898/61009, the 0.4 s and 5 s values are the same, except Type D.
• For Type D, the 0.4 s value is much lower, so the external impedance Ze must be very low. Zs = Ze + (R1+R2).
• BS 3871 Type 4 values vary wildly between makers. If you use manufacturer's data, attach it to the EICR.

Under BS 7671:2018, an RCD of 30 mA or less must trip within 40 ms at 5 × IΔn (Reg 643.8 note). The 1 × IΔn test is no longer required but is still good practice. A much faster result than last time suggests nobody uses the test button.

Which type for which load

• AC: plain resistive, capacitive or inductive loads. Immersion heaters, resistive ovens and hobs, electric showers, tungsten and halogen lighting.
• A: single-phase with electronics. Inverters, dimmers, LED drivers, induction hobs, most washing machines, Class II power supplies, EV charging with DC fault current under 6 mA. Also covers AC applications.
• F: frequency-controlled. Some washing machines, dishwashers and driers, some Class I power tools, variable-speed air conditioning. Also covers A and AC.
• B: three-phase electronics. Inverters, UPS, PV, EV charging with DC fault current over 6 mA, industrial machines. Also covers AC, A and F.

Follow the manufacturer's instructions where they say otherwise.

BS 7671:2018 isn't retrospective, but EICRs are judged against the current edition.

SPD required (Reg 443.4) where overvoltage could cause

• Serious injury or loss of life
• Loss of public services or damage to cultural heritage
• Loss of supply to a business or industrial activity
• Risk to a large number of co-located people

Elsewhere, do the Reg 443.5 risk assessment (Tools tab has a CRL calculator). A CRL of 1000 or more lets the designer or client leave SPDs out. Under 1000 means fit them. With no assessment, SPDs must be fitted.

Single domestic dwelling: the client can choose to go without if they judge the extra cost outweighs what the SPD would protect. No assessment is needed.

SPD inspection checklist

• Cable size at least 6 mm² for Type 2, 16 mm² for Type 1 (Reg 534.4.10 or manufacturer).
• Cables preferably no longer than 0.5 m, never over 1.0 m (Reg 534.4.8). If longer, an intermediate earth terminal or extra SPDs closer to the equipment.
• Label shows type: T1 at the origin of metallic services where the building has lightning protection. T2 at the origin where it hasn't, and where cables cross internal zone boundaries. T3 within 10 m of the end equipment.
• Status window: red or tell-tale means the SPD may need replacing. LED indicators are off during a power-down test, so true status is unknown until power is restored.
• Fuse for the SPD circuit: check lower-rated fuses haven't been fitted, and the fuse is intact. The whole SPD assembly must be rated at least the prospective short-circuit current there (Reg 534.4.4.7). Check any isolator in the SPD circuit is closed.
• kA rating: 5 kA per pole for Type 2 and 12.5 kA (Iimp) per pole for Type 1 in CT1 connections (Regs 534.4.4.4.1 and .2). See both regulations for CT2 values on TT supplies.
• Voltage protection level Up must not exceed the installation's required withstand voltage (Table 443.2). Consult the client if it does. Cable length affects the installed Up.
• SPD before the RCD with the CT2 connection is the only safe method there (Appendix 16, Fig 16A3), and the SPD should be marked for TT. SPD after the RCD (Fig 16A2) needs a type S RCD with 3 kA surge immunity, or the RCD is likely to be damaged.
• Cables crossing zones 0/1 (phone lines, TV coax, outside circuits, roof plant) need protecting where the client requires it.
• All SPDs on the same line or circuit must be a coordinated family. No mixing makers unless coordination has been tested.

Surge routes include TV and satellite coax, overhead phone lines, CCTV, outside and security lighting and electric gates.

Breaking these rules always earns a C2, because the protective device isn't deemed to be protecting the circuit. The rules ignore RCDs, SPDs, AFDDs and derating, which must be assessed as well.

Ring final circuit must

• Start and finish at the CU/DB
• Have continuity of all conductors along its length
• Be on a 30 or 32 A maximum protective device
• Use conductors rated for that device: at least 20 A for a 30/32 A device, at least 15 A for a 20 A device
• Not be part of a radial circuit
• Have no bridging link
• Historically cover up to 100 m²

Spurs on a ring

• Supply only one un-fused accessory (a single or double socket) or one fused connection unit (FCU) supplying a single piece of fixed equipment.
• Where several sockets are added, protect them with an FCU first.
• Un-fused spurs use the same rated conductor as the ring. After an FCU the conductor rating may drop (to at least above 13 A), because the FCU stops an overload upstream of it.

Radial final socket circuit must

• Start at a DB/CU, protected by a device suited to the lowest-rated conductor
• Have continuity of all conductors
• Not include a ring
• Not exceed 32 A for socket circuits
• Historically cover up to 50 m² on a 20 A device, or 75 m² on a 30/32 A device

Spurs on a radial

• Un-fused accessories fed by conductors adequately rated for the protective device, or FCUs supplying single items of fixed equipment.
• Where conductor size is reduced downstream, an FCU must protect it.
• A reduced-size spur (for example 2.5 mm² off a 4.0 mm² circuit) is allowed for one spur only. The 13 A fuses in the plug and socket arrangement protect it. Taking multiple accessories from that same reduced spur is not acceptable. You may also spur one accessory straight from the device in the CU/DB with the reduced size.

The book has diagrams of these layouts on book pages 159–162.

• Recommended by Reg 421.1.7.
• Some have a test button. There's no set frequency (RCDs: every 6 months). Ask the client before pressing it.
• After a test the device should disconnect. The tell-tale window may show an amber flag.
• A colour other than its normal state (often a green flag) means it detected a fault, or its self-test failed. Either way it disconnects the circuit.

Coding

• Tripped on a fault, cause not obvious: C2 or FI. It only remakes if the fault is gone.
• Failed self-test: it won't remake and has to be replaced. There's an argument for a C2, but the book calls that harsh (the circuit can't be energised). It suggests C3 as more realistic.

Insulation resistance with AFDDs

Test voltages above 250 V are very likely to damage them. A global 500 V test is out. Instead:

• Live to live: disconnect one live conductor from the AFDD. 500 V is then fine.
• To earth: test live–earth, neutral–earth, and live and neutral joined–earth. 500 V is fine.

Earth fault loop impedance

AFDDs contain coils like an RCD, so set the instrument to its no-trip (RCD) setting when testing a circuit with an AFDD.

An EICR only covers BS 7671. For anything outside it, you can:

1. Do nothing.
2. Add a comment on the EICR and tell the client no code can be given and they should use a specific contractor.
3. Agree in the limitations that you'll write a separate report against the relevant standard.

Common examples

• Gas meter or pipes near electrics: segregation is set by BS 6891, not BS 7671 (minimum distances are in book Table 6.2).
• Emergency lighting (BS 5266): positioning, type, number, lumens, operation and testing aren't EICR items. Wiring faults still are.
• Fire and smoke alarms (BS 5839): positioning, type, number, sound level, interconnection and testing aren't EICR items. Wiring faults still are.
• Socket distance from sinks and cookers: BS 7671 sets no minimum. The book gives industry guidance only, such as 100 mm from a hob and no sockets above hobs or sinks (book p.170).

Best practice: feed smoke alarms from a commonly used lighting circuit, so they're less likely to be isolated deliberately.

• Electricians are an at-risk trade. See HSE L143 and the Control of Asbestos Regulations 2012.
• Before starting, ask for the Asbestos Management Plan/Register.
• Old switchgear, distribution boards, consumer units and BS 3036 fuse carriers often contain asbestos (as packing or arc covers).
• If you find damaged or suspect material, make sure you and others are safe, and tell the client at the earliest opportunity.

1. Check with the occupier that it's acceptable to isolate.
2. Identify the supply type (TN-S, TN-C-S, TT) and the means of isolation.
3. Locate and identify the circuit or equipment to isolate.
4. Select an approved voltage indicator.
5. Prove the indicator on a known supply or proving unit.
6. Isolate and secure the circuit (switch off, remove fuse or lock off).
7. Fit a lock-off device and keep the key.
8. Fit a warning label.
9. Test the circuit is dead between all conductors (L–N, L–E, N–E).
10. Re-check the indicator on the same known supply or proving unit as step 5.
11. If the check fails, don't work on it. Investigate.
12. Circuit is safe to work on.

To re-energise: inspect and test (Part 6), remove locks and labels, restore supply, complete live tests, then issue certificates.

Rebuilt from the book's flowchart (book p.176). The commercial and industrial version is on book p.177.

All 636 observations from Part 1 of the NAPIT Codebreakers book (Sections 1–7), each with its code, regulation and book page. About 200 of the longer or harder ones have an “In plain terms” line that I wrote. Those are paraphrases, not the book’s wording, so keep the book’s text for the report.

Certificates: EICR, EIC and minor works documents in the IET’s A4 model-form layout, with a “before you issue” checklist. The IET allows its forms to be reproduced for your own contracting business without its logo, and says it hasn’t checked them. Check your scheme provider’s requirements before issuing.

Also: remedial tracker with a 28-day clock and completion letters, property folders and landlord packs, customer reminders by SMS, WhatsApp or email, a test instruments register, cable size and voltage drop, and tester CSV import.

Walk-through follows the IET’s A4 schedule of inspection. Report collects observations with locations, photos and suggested remedial jobs. Customer summary turns it into plain English. Saved reports support follow-up visits.

The book is a scan, read by OCR. Codes were checked two ways and several pages checked by eye. About 4% of regulation numbers may still be misread. The book predates Amendment 4, so see Tools → Changes since the book. Always confirm against the printed book and the current BS 7671.

Not reproduced: the full risk-assessment forms and the figure diagrams. The book page numbers show where to find them.