Electrical Installation Certificate Example UK

A Complete Worked Example: New Consumer Unit in a Domestic Property

Below is a realistic electrical installation certificate (EIC) based on a sole-trader electrician carrying out a consumer unit replacement in a three-bedroom semi-detached house. This is one of the most common notifiable jobs in domestic electrical work, and it illustrates every mandatory section of the certificate. Work through it field by field before reading the explanation sections that follow.

Job details: Electrician: James Hartley Electrical, sole trader, NICEIC registered. Address of installation: 14 Birchwood Close, Sheffield, S6 3TF. Date of work: 14 March 2025. Description of work: Replacement of existing consumer unit with a new 18-way dual RCD consumer unit, including installation of AFCI protection on bedroom circuits. BS 7671:2018 Amendment 2:2022 edition referenced. Works classified as notifiable under Part P.

Supply characteristics: Earthing arrangement: TN-C-S (PME). Nominal voltage: 230 V. Frequency: 50 Hz. Prospective fault current (Ipf) at origin: 1.8 kA. External earth fault loop impedance (Ze): 0.28 ohms. Confirmed by measurement on site. Supply protective device: 100 A BS 1361 service fuse (confirmed with network operator records).

Schedule of circuit details: Circuit 1, lighting ground floor, 6A Type B MCB, 1.5 mm2 twin and earth, 18 m, Zs 0.72 ohms, RCD protected 30 mA. Circuit 2, lighting first floor, 6A Type B MCB, 1.5 mm2 twin and earth, 21 m, Zs 0.84 ohms, RCD protected 30 mA. Circuit 3, ring final sockets ground floor, 32A Type B MCB, 2.5 mm2 twin and earth, 42 m total ring, Zs 0.38 ohms, RCD protected 30 mA. Circuit 4, ring final sockets first floor, 32A Type B MCB, 2.5 mm2 twin and earth, 38 m, Zs 0.35 ohms, RCD protected 30 mA. Circuit 5, cooker, 32A Type B MCB, 6 mm2 twin and earth, 12 m, Zs 0.61 ohms, RCD protected 30 mA. Circuit 6, shower 9.5 kW, 40A Type B MCB, 10 mm2 twin and earth, 9 m, Zs 0.54 ohms, RCD protected 30 mA. Circuit 7, immersion heater, 16A Type B MCB, 2.5 mm2 twin and earth, 14 m, Zs 0.67 ohms, RCD protected 30 mA.

• •Insulation resistance (line-line and line-earth): all circuits above 200 MOhm at 500 V DC
• •Polarity: confirmed correct on all circuits
• •Earth continuity: all CPC resistances measured and recorded
• •RCD operating times: 30 mA RCDs tripped within 40 ms on all circuits tested
• •AFCI devices fitted to circuits 1 and 2 per Regulation 421.1.7 of BS 7671:2018 Amendment 2:2022
• •Part P notification submitted to LABC Sheffield on 14 March 2025, notification reference SP2025-03847

The Legal Framework Behind the Certificate

The electrical installation certificate is not a form you fill in because it looks professional. It is a statutory requirement. Part P of the Building Regulations 2010 requires that most electrical work in dwellings either be notified to local authority building control (LABC) or be carried out and certified by a registered competent person scheme member such as NICEIC, NAPIT, or Elecsa. Failure to notify notifiable work is a criminal offence under section 35 of the Building Act 1984, with fines of up to £5,000.

BS 7671:2018 Amendment 2:2022 (the 18th Edition Wiring Regulations) is the technical standard that the certificate must reference and comply with. Regulation 631.1 of BS 7671 requires that on completion of an installation or an addition or alteration to an existing installation, an electrical installation certificate together with a schedule of inspections and a schedule of test results shall be given to the person ordering the work. That recipient is usually your customer. You must hand it over, not keep it yourself.

For landlords, there is an additional layer. The Electrical Safety Standards in the Private Rented Sector (England) Regulations 2020 require that landlords obtain a satisfactory EICR (electrical installation condition report) at least every five years. An EIC from new installation work does not replace an EICR for this purpose, but it does form part of the installation history that future inspectors will rely on. Getting your EIC right today protects the next electrician and, frankly, protects your own professional standing if there is ever a dispute.

Under the Consumer Rights Act 2015, section 49, any service you provide to a consumer must be carried out with reasonable care and skill. An incomplete or inaccurate certificate is direct evidence that you have not met that standard. If a fault occurs later and your certificate shows a Ze you never actually measured, or an Ipf figure copied from a previous job, you are exposed to a civil claim with a six-year limitation window under section 5 of the Limitation Act 1980.

Breaking Down the Designer, Constructor and Inspector Sections

The standard EIC form from the IET or your competent person scheme has three signature boxes: Designer, Constructor, and Inspector/Tester. For a sole trader doing a straightforward domestic job, all three are usually you. That is entirely legitimate and common, but you must complete all three sections. Leaving the designer box blank because you assumed it was for commercial jobs is one of the most frequent mistakes on EICs.

The designer section confirms that the design meets BS 7671. Even swapping a consumer unit involves design decisions: the earthing arrangement, the type of RCD protection, the selection of MCB ratings, and whether AFCI protection is required under Regulation 421.1.7. Write your name, your registration number, and the date you confirmed the design. If the design was done by someone else, that person signs the designer box and you sign constructor only.

The constructor section is your confirmation that the installation was built to the design. The inspector/tester section is your confirmation that the completed installation was inspected and tested in accordance with Part 6 of BS 7671. All three dates can be the same for a one-day job. What matters is that all three fields are completed and legible.

• •Designer: confirms design complies with BS 7671:2018 Amendment 2:2022
• •Constructor: confirms work was carried out to the design
• •Inspector/Tester: confirms inspection and testing was completed per BS 7671 Part 6
• •All three can be the same person on a sole-trader job
• •Registration number, signature, and date are mandatory in each box

Supply Characteristics and Earth Fault Loop Impedance: Measure, Do Not Guess

The supply characteristics section trips up more electricians than any other part of the certificate. The earthing arrangement (TN-S, TN-C-S, TT, or IT), the prospective fault current (Ipf), and the external earth fault loop impedance (Ze) must be measured or confirmed on site. Writing figures from memory, using a neighbouring property's results, or simply copying the previous certificate is professionally indefensible and potentially dangerous.

In the worked example above, Ze was measured at 0.28 ohms. For a TN-C-S (PME) system in an urban area, that is a realistic figure. An Ipf of 1.8 kA is similarly typical. However, these figures vary street by street and even house by house depending on network infrastructure. If you cannot access the tails to measure Ze directly, you must use an approved alternative method and note it on the certificate, not just leave the box blank or insert a figure you consider reasonable.

The maximum permitted earth fault loop impedance (Zs) for each circuit must be recorded in the schedule of test results and must not exceed the values given in Tables 41.2 to 41.6 of BS 7671. For the ring final socket circuit in the example above, the measured Zs of 0.38 ohms is well within the 1.44 ohm limit for a 32A Type B MCB under Table 41.3. You need to show that calculation, or at least the measured result, clearly.

A common error is failing to apply the temperature correction factor. Test results are taken at ambient temperature, but the standard requires compliance at maximum operating temperature. The correction factor for copper conductors is typically 1.2 applied to the ambient-temperature Zs measurement to give the value at operating temperature. If your corrected Zs exceeds the permitted maximum, the circuit does not comply, and you cannot certify it as satisfactory.

The Schedule of Inspections: What You Actually Checked

The schedule of inspections is a tick-list of every visual check carried out before testing. It covers items including: correct identification of conductors, presence and adequacy of earthing and bonding, routing of cables in safe zones or protected by RCD, connection of conductors, selection of equipment, and so on. The full list is derived from Chapter 61 of BS 7671 and the IET's Guidance Note 3 on inspection and testing.

Every item must be marked as satisfactory (tick), not applicable (N/A), or a limitation noted. Do not leave items blank. A blank field on an inspection schedule is ambiguous. Was it missed? Was it inaccessible? Did you not bother? An LABC inspector, a scheme auditor, or a solicitor instructed by a claimant will ask that question. Mark N/A where it genuinely does not apply and note any limitations in the limitations box on the front of the certificate.

For the consumer unit replacement example, items such as presence of fire barriers within the consumer unit enclosure and correct application of the 1 m rule for PME earthing connections are inspection items that electricians sometimes skip because they seem obvious. They are not optional on the form.

• •Identification of conductors: correct colour coding confirmed (brown live, blue neutral, green/yellow CPC)
• •Earthing and bonding: main protective bonding to gas, water, and structural steel confirmed
• •Cable routing: cables in safe zones or mechanically protected throughout
• •RCD protection: 30 mA RCDs protecting all socket circuits as required by Regulation 411.3.4
• •Consumer unit: metal consumer unit fitted in compliance with Regulation 421.1.201 of BS 7671 Amendment 2:2022
• •Fire barriers: compartmentation within consumer unit enclosure confirmed

Test Results: The Numbers That Actually Matter

The schedule of test results is the numerical heart of the certificate. For each circuit you must record: the circuit description, the overcurrent protective device type and rating, the cable cross-sectional area and type, the design current, the maximum permitted Zs, the measured insulation resistance (IR) values at 500 V DC, the measured Zs, the measured RCD operating time at 1x and 5x rated tripping current where applicable, and polarity confirmation.

In the worked example, circuit 6 (the 9.5 kW shower) uses a 10 mm2 cable with a measured Zs of 0.54 ohms. For a 40A Type B MCB, the maximum permitted Zs from Table 41.3 is 1.04 ohms, so 0.54 ohms passes comfortably. But note that the overcurrent protection for a 9.5 kW load at 230 V draws approximately 41 A at full load. A 40A MCB is technically marginally loaded. The correct approach is to confirm that the cooker control unit or isolator is rated for the load and that diversity factors do not apply in a way that creates sustained overload.

Insulation resistance results in the example are recorded as above 200 MOhm on all circuits. In practice, if any circuit reads below 1 MOhm it should be investigated before the installation is certified. A result of exactly 200 MOhm is a red flag: it may mean the meter has reached its upper display limit. Record the actual reading your instrument shows, including the upper limit notation if applicable, and use a calibrated instrument with a current calibration certificate.

RCD operating times must be tested at 50% rated tripping current (should not trip within 300 ms), at 100% rated tripping current (must trip within 300 ms), and at 500% rated tripping current (must trip within 40 ms). For a 30 mA RCD those test currents are 15 mA, 30 mA, and 150 mA respectively. Record all three results, not just the 5x result.

Part P Notification: When and How

Part P of the Building Regulations 2010 applies to electrical installations in or associated with a dwelling. Notifiable work includes: installing a new circuit, replacing a consumer unit, and work in special locations such as bathrooms, swimming pools, or locations with limiting dimensions. Adding a spur to an existing ring final circuit in a kitchen is also notifiable if it is in a kitchen and involves a new circuit to supply a fixed appliance.

If you are a registered member of a competent person scheme (NICEIC, NAPIT, Elecsa, STROMA, or similar), you self-certify by notifying your scheme within the timescale they specify, typically 30 days. Your scheme then notifies LABC on your behalf and issues a building regulations compliance certificate to the homeowner. That compliance certificate is not the same as the electrical installation certificate. Both must be given to the homeowner.

If you are not scheme-registered, you must notify LABC before work begins or immediately on starting work. LABC will inspect and issue a completion certificate on satisfactory conclusion. Either route is lawful, but scheme registration is the practical standard for sole traders doing regular domestic work because LABC fees and inspection delays are avoided. The penalty for failing to notify is enforcement action under the Building Act 1984, plus the homeowner being unable to demonstrate compliance when they come to sell the property. That creates a civil claim against you.

• •New circuits in dwellings: notifiable
• •Consumer unit replacements: notifiable
• •Work in bathrooms, shower rooms, and swimming pool zones: notifiable
• •Adding a socket to an existing ring final outside a special location: not notifiable if no new circuit
• •Work in garages, outbuildings, and garden buildings connected to the house supply: notifiable
• •Scheme self-certification deadline: typically 30 days from completion (check your scheme rules)

Common Mistakes That Will Come Back to Bite You

The Ze box contains a figure that matches the previous EIC for the property. This is the single most common mistake on consumer unit replacements. The supply infrastructure changes over time. Network operators replace cables, add or remove neutral-earth links, and alter transformer impedances. Measure Ze on every job, every time.

The schedule of test results is missing circuits. On a real installation this often happens when the original consumer unit had more circuits than the replacement, or when the electrician forgot to record the smoke alarm interlink circuit or the garage circuit. Every circuit that exists after your work must be on your schedule. If there were already circuits present that you did not touch, they must appear in the schedule with at minimum an annotation confirming they were not part of the current work but were visually inspected.

The certificate is not given to the customer at practical completion. BS 7671 Regulation 631.1 requires the certificate to be given to the person ordering the work. Emailing it three weeks later is not compliance. If you hand over a paper copy on the day, note that on your job record. If you use a digital certificate, ensure the customer has actually received and can access it, not just that you sent an email.

The AFCI requirement is ignored. Regulation 421.1.7 of BS 7671:2018 Amendment 2:2022 requires arc fault detection devices (AFDDs) to be installed on final circuits supplying socket outlets in high-risk premises including houses of multiple occupation (HMOs) and on circuits supplying socket outlets in bedrooms of other dwellings. The requirement applies to new and replacement consumer units. Not fitting AFDDs where required and not noting a reason for their absence is a certifiable defect.

Variations: Minor Works, EICRs, and Landlord Situations

An electrical installation certificate is not the correct document for every job. A minor electrical installation works certificate (MEIWC) is used when work involves an addition or alteration to an existing circuit and does not constitute a new circuit. Adding an extra socket to an existing ring final, for example, requires a MEIWC rather than a full EIC. The MEIWC requires fewer test results but still requires insulation resistance, earth continuity, and polarity checks, plus confirmation that the existing installation is adequate for the addition.

For landlords and letting agents, the relevant document for periodic inspection is the electrical installation condition report (EICR), governed by the Electrical Safety Standards in the Private Rented Sector (England) Regulations 2020. Under Regulation 3 of those Regulations, a landlord must ensure that the electrical safety standards in the 18th Edition Wiring Regulations are met, that an inspection is carried out at least every five years by a qualified person, and that a copy of the EICR report is given to existing tenants within 28 days and to new tenants before they occupy. The fine for non-compliance is up to £30,000 per breach.

In commercial premises, the same general principles of BS 7671 apply but the EIC form and the obligation to notify under Part P do not apply (Part P is domestic only). For commercial work you are still required under the Health and Safety at Work etc. Act 1974 (section 2 general duties, and section 3 duties to non-employees) to ensure the installation is safe. An EIC or equivalent test certificate is the practical evidence that you have done so. Many commercial clients require it under the terms of their insurance policies and the Electricity at Work Regulations 1989.

• •EIC: new circuits, consumer unit replacements, new installations
• •MEIWC: additions or alterations to existing circuits (new sockets, extending a circuit)
• •EICR: periodic inspection and testing of existing installations, including landlord five-yearly inspections
• •Landlord EICR fines: up to £30,000 under the Electrical Safety Standards in the Private Rented Sector (England) Regulations 2020
• •Commercial EIC: no Part P requirement but required by BS 7671, H&S legislation, and most commercial insurance policies

Pricing, VAT, and CIS on Electrical Certificate Work

For a sole trader, the job that generates an EIC is typically a one-off domestic contract. Under the Consumer Rights Act 2015, section 51, where a price has not been agreed in advance the customer is only required to pay a reasonable price. This rarely causes problems on jobs where you have quoted in writing beforehand, but if you quoted verbally and the customer disputes the invoice, section 51 becomes relevant. Get your quote in writing every time.

VAT on domestic electrical installation work is standard-rated at 20%. However, where the work is an energy-saving installation such as the installation of certain insulation materials or controls, reduced rating at 5% may apply under VAT Notice 708. For a standard consumer unit replacement or new circuit installation in a dwelling, 20% applies. The domestic reverse charge under VAT Notice 735 applies where you are a VAT-registered subcontractor supplying services to a VAT-registered contractor who in turn supplies those services onward. This is relevant if you work for a main contractor, not if you work directly for a homeowner.

If you work as a subcontractor for a contractor who is registered under the Construction Industry Scheme, the contractor must deduct CIS tax at 20% (verified) or 30% (unverified) from your labour element before paying you, under the Income Tax (Construction Industry Scheme) Regulations 2005. Domestic electrical installation work for homeowners direct is not within CIS. CIS applies to construction operations as defined under the Finance Act 2004, and construction operations do not include work on a dwelling that is the private residence of the person commissioning the work where the work is carried out by a person engaged directly by that householder.

Generate Your Certificate in About Two Minutes with TradeDoc

Filling in an EIC by hand or working from a generic PDF template is time-consuming and prone to the kind of errors this guide has described. TradeDoc (tradedoc.co.uk) is a document generation tool built for UK sole-trader tradespeople that produces correctly structured electrical certificates, minor works certificates, and other trade documents with all the mandatory fields pre-mapped to current BS 7671 and Part P requirements.

You enter the job details, the test results, and your registration information, and TradeDoc generates a completed certificate you can send directly to the customer or print on site. It takes around two minutes per certificate once your details are saved, and the output reflects the current 18th Edition requirements including the AFDD notation fields introduced by Amendment 2:2022.

It does not replace your professional judgement or your obligation to actually carry out the tests. But it does mean you are not wrestling with a PDF on your phone in a van at 6pm trying to remember whether the circuit description goes in column 3 or column 4.