10.1 Purpose, Scope & Limitations of Periodic Inspection

Purpose of Periodic Inspection

A periodic inspection of an existing electrical installation is carried out to determine whether the installation is in a satisfactory condition for continued safe use. The outcome is recorded on an Electrical Installation Condition Report (EICR). The critical distinction is what the inspection is not: it is not a certification that new work complies with BS 7671 — that is the function of an Electrical Installation Certificate (EIC) issued after initial verification. A periodic inspection reports the condition at the time of inspection; it is a snapshot, not a warranty for the future.

The purpose, as set out in BS 7671 and GN3 (10th Edition, 2026), is to:

• identify any damage, deterioration, defects, or dangerous conditions;
• identify any non-compliance with the current edition of BS 7671 that presents or may present danger;
• ensure the installation is safe for continued use until the next inspection;
• provide the dutyholder or owner with a record of the installation's condition so remedial work can be planned.

Because BS 7671 is updated periodically (the current edition is BS 7671:2018+A4:2026), an installation that complied when it was first certified may no longer comply in every detail. The inspector judges each deviation on whether it presents or may present danger, not merely whether it differs from the latest text.

Reasons for Periodic Inspection

A periodic inspection is triggered by several reasons. The most common are summarised below.

Note the change of tenancy or ownership trigger: a domestic installation may be inspected more frequently than every 10 years if the occupancy changes, because a new occupier may use the installation differently — placing heavier loads on circuits that were previously lightly loaded. A periodic inspection after flood or fire is also common: the visible wiring may look intact, but water ingress or heat can damage insulation and terminations that only testing will reveal.

Scope and Limitations

The scope of a periodic inspection is agreed with the client before the inspection begins. The inspector and client agree what is included — typically the entire installation from the origin (the supply intake) onwards — and, crucially, what is excluded.

There are two categories of limitation:

• Agreed limitations — negotiated with the client in advance. Examples: not lifting floor coverings, not moving heavy furniture, not isolating essential equipment (such as a server room that cannot be shut down), not testing certain circuits that cannot be de-energised.
• Operational limitations — things the inspector could not reasonably access or do on the day. Examples: concealed wiring behind fixed structures, terminations inside sealed equipment, circuits that could not be isolated because the lock-off key was unavailable.

Both categories are recorded on the EICR. The reason is twofold: they bound the inspector's responsibility (the inspector is not liable for what was not examined), and they inform the user or dutyholder that those areas were not assessed and may need separate investigation.

Why Limitations Matter

An EICR carrying heavy limitations has reduced certainty — the inspector could only report on what was accessible. A responsible inspector draws the client's attention to significant limitations before signing the report, and may recommend a further inspection once the limitations can be removed (for example, once floorboards are lifted or equipment is isolated). Limitations are not a way to avoid work; they are an honest statement of what was and was not done.

The client must understand that a report stating "50% of accessories not inspected due to agreed limitations" cannot give the same confidence as one with full access. Where a limitation prevents confirmation of safety-critical items (earthing, bonding), the inspector should consider whether an FI code is appropriate (covered in section 10.3).

The Legal and Dutyholder Context

For landlords and employers, a current EICR is often a legal or contractual requirement, not merely a recommendation. The Electricity at Work Regulations 1989 require that electrical systems be maintained so as to prevent danger, and a periodic inspection is the standard way to demonstrate compliance. Private sector landlords in England are required to have an EICR carried out at least every 5 years (or on change of tenancy), and must remedy any C1 or C2 defect within 28 days. The inspector's report is therefore evidence both for the dutyholder and for any enforcing authority. Understanding this context helps the inspector explain to the client why a C1 or C2 cannot wait, and why the report must be delivered promptly and without ambiguity.

EICR vs EIC — A Summary