3.4 Why the Documents Exist: Reasons, Information Needed, Recording & Retention

Why an Inspection Happens at All

Assessment criterion 1.2 asks you to explain reasons for conducting types of inspection and testing, and the qualification specification lists them explicitly. They are worth learning as a set, because a question will often give you a scenario and ask which reason applies.

The first three are essentially external obligations imposed on the duty holder; the last four are changes in the installation or its use. An exam scenario that mentions a landlord, an insurer, or a licence is pointing at the first group.

Information the Inspector Needs Before Starting

Assessment criterion 1.6 lists three things you must establish before any test lead is connected.

1. Information to carry out the work to BS 7671 and GN3

• The design — circuit schedules, distribution board records, the intended use and the maximum demand.
• Previous certification — the original Electrical Installation Certificate, any Minor Works Certificates, and the most recent Condition Report. These give you the baseline Ze, prospective fault current and earthing arrangement, and tell you what has changed.
• The characteristics of the supply — earthing arrangement, nominal voltage, number of phases, and the protective device at the origin.
• Details of any special locations or equipment on site that bring additional requirements.

Where records do not exist — common on older installations — that absence is itself a finding. The inspector must then determine the supply characteristics by measurement and enquiry, and record the lack of records on the report.

2. Agreeing the extent and limitations

The extent is what the inspection covers: the whole installation, one distribution board, one floor. The limitations are what it does not cover, and they come in two flavours — those agreed with the client in advance (not lifting fitted floor coverings, not shutting down a server room) and those the inspector meets on the day (a locked plant room, a sealed accessory). Both are recorded.

Agreeing this in writing before starting protects everybody. The client knows what they are buying; the inspector knows what they are responsible for; and the person who reads the report in three years knows what was never looked at.

3. Determining the sampling regime

Periodic inspection is carried out on a sample rather than 100% of the installation. The proportion is the inspector’s professional judgement based on age, condition, usage and the records available — and it is agreed with the client, recorded on the report, and extended if defects appear. Sampling is covered fully in section 10.2.

Initial Verification and Periodic Inspection Compared

Assessment criterion 1.3 asks you to compare the two processes. The comparison is worth holding as a table, because exam stems frequently describe one and offer answers drawn from the other.

The last row is the one candidates most often get wrong. An installation wired to the 16th Edition is not automatically unsatisfactory because it no longer matches BS 7671:2018+A4:2026. The inspector asks whether the deviation presents or may present danger.

Purpose of the Documents, and the Recording Requirements

Assessment criterion 1.9 asks you to describe the purpose of the inspection and testing documents and the requirements for recording and retention. The purpose runs on three levels.

1. Evidence of compliance. BS 7671 is not law, but the Electricity at Work Regulations 1989 are. A certificate or report is the practical evidence that the duty holder took reasonable steps to construct or maintain a safe system. Without it, the duty holder has an assertion; with it, they have a record made by a named competent person on a stated date.
2. A technical baseline. The recorded Ze, prospective fault current, R1+R2, insulation resistance and Zs values are what the next inspector compares against. A circuit whose insulation resistance has fallen from 200 MΩ to 3 MΩ over ten years is still above the 1 MΩ minimum, but the trend is the finding — and you can only see it if the earlier figure was recorded.
3. Communication. The report tells a non-technical owner what is wrong, how urgent it is, and what to do next.

What must be recorded

• Supply characteristics — earthing arrangement, nominal voltage and frequency, number and type of live conductors, Ze and prospective fault current at the origin, and the protective device at the origin.
• Every circuit, on the schedule of circuit details: reference, description, conductor sizes, protective device type, rating and short-circuit capacity, and RCD details.
• Every test result, on the schedule of test results — the measured values, not ticks.
• Every inspection item, on the schedule of inspections.
• The instruments used — type and serial number, so the results can be traced to a calibration certificate.
• The extent and limitations, and for a condition report, the sampling applied.
• Names, signatures, capacities and dates for each signatory.

Distribution and retention

The original certificate or report goes to the person ordering the work, who should pass it to the owner or occupier of the installation. The inspector or contractor keeps a copy.

Certificates and reports should be retained for the life of the installation — an Electrical Installation Certificate stays relevant for decades, because it records what was installed and to what standard. On sale or transfer of the premises they should be handed to the new owner, together with any Minor Works Certificates and previous Condition Reports. In practice they are held with the operation and maintenance manual or the building’s health and safety file.

A certificate issued today should still be legible and meaningful to an inspector opening the consumer unit in 2036. That is the standard to write to: complete circuit descriptions, actual measured values, and limitations spelled out rather than abbreviated.