Periodic Inspection and Testing of Electrical installations

Periodic Inspection and Testing explained

Purpose of Periodic inspection and testing

To ascertain whether an electrical installation is in a satisfactory condition, such that it can continue to be used safely.

Why is periodic inspection and testing necessary?

All electrical installations deteriorate for many reasons, including damage, excessive electrical loading and environmental influences. Not to mention the wear and tear as a result of daily use.

Predominantly, periodic inspection and testing is carried out to ensure the safety of persons (and livestock) against the effects of electric shock and burns. Additionally, it is vital to reduce the risk of fire as a result of the heat produced from an electrical installation.

What does a periodic inspection and test consist of?

Typically, a periodic inspection consists of three parts:

  1. Visual inspection – This involves visually inspecting the parts of the installation without removing any covers. Items to be visually inspected will include but are not limited to sockets, switches, light fittings, appliance connection plates / Fused Connection Units (FCU's) wired-in appliances, exposed cabling and fuse boxes / consumer units. The electrician will also need to access the distributors equipment (meter box) and any earthing and bonding connections (green / yellow cable connected to earth rods, metallic parts of the building, metal pipes, gas or oil pipes).
  2. Physical inspection – A proportion of items contained within the installation will be physically inspected by removing the covers to check the wiring for deterioration. The proportion of items chosen to be physically inspected will depend on the condition of the fixed wiring and accessories found during the visual inspection and may be increased during the physical inspection.
  3. Electrical testing – Electrical testing is undertaken to determine whether the protective devices (such as fuses, circuit breakers, residual current devices) will operate as intended under fault conditions.

Will the power need to be switched off?

During the visual inspection stage the power should be on. During the physical inspection stage, parts of the installation may need to be switched off and locked off while covers are removed for safety reasons.

Whilst limited periodic inspection and testing can be carried out to commercial and industrial premises without switching off to ensure continuation of business, this is not appropriate for domestic properties. Switching off is essential to test residual current devices for example, particularly those which are relied upon to provide automatic disconnection of supply in earth fault conditions.

The electrician will endeavour to work with the occupier to ensure a convenient time for switching off the installation and ensure any disruption is minimised.

It is the responsibility of the occupier to ensure that any sensitive electrical appliances plugged-in to the installation are disconnected (un-plugged) prior to tests being carried out. This includes but is not limited to: TV’s, computer equipment and audio equipment.

I have a periodic inspection booked. Do I need to do anything to prepare for it?

The electrician will want to see the installation as it is normally used. However, please ensure that sockets and switches are generally accessible and there is sufficient space to work at the consumer unit and the hot water tank. In domestic properties lofts or voids will also need to be inspected. This is particularly important for older properties.

For safety of the engineer, please ensure that young children and animals remain outside the work area at all times during the inspection and test.

How long will the inspection and test take?

This can vary greatly. For relatively new, small domestic installations with no accessibility issues and with previous installation schedules available it can take less than 2 hours. For larger installations or if defects or deterioration are identified it may take much longer, or in some cases a return visit. Larger commercial or industrial installations are typically split into parts (scoped), each part with its own report. This typically reduces disruption to business.

What information will the electrician need to record during the inspection and testing?

  • Details of the electrical installation including the circuits in the premises;
  • Details of their observations regarding the condition of the installation;
  • Photo(s) taken depicting any defect / damage or non-compliance relating to the electrical installation (these will be reproduced in the report).

Typically, within 2 working days the occupier (and proprietor) of the premises with receive by email a copy of the Electrical Installation Condition Report (EICR) for the inspection carried out. This will contain a list of any faults and non-compliances identified, classified into the following codes:

  • C1 – Danger present – Immediate remedial action required.
  • C2 – Potentially dangerous – Urgent remedial action required
  • C3 – Improvement required
  • FI – Further investigation required without delay

Please note that the final conclusion of the EICR will be either “satisfactory” or “unsatisfactory”. Should a single observation attract a code of C1, C2 or FI then the overall assessment of the condition of the electrical installation is “unsatisfactory”.

Where a defect or fault is attributed a code of C1 this ideally would be made safe by the engineer before leaving site. Where this is not possible, partial isolation of the installation may be required to render the installation safe. Please note that any remedial work carried out relating to observations noted on the EICR will attract additional charges at the published rates.

Please remember that the purpose of Periodic Inspection and Testing is to ascertain the condition of an installation, not fix the faults or in any way certify a new installation or work carried out by others not competent to do so.


Limitations are any constraints placed on the inspection and testing process which have the potential to reduce the validity of the conclusions drawn by the assessor. Limitations may take the form of physical obstructions preventing access to parts of the installation, lack of permission to access parts of the installation, insufficient time to carry out an inspection and test or not be able to isolate necessary parts of the installation to undertake testing. Any limitations encountered will be noted on the report and a reason provided. Please note that limitations reduce the usefulness and potentially the validity of any conclusions drawn. Materially limited inspections will typically not satisfy regulatory bodies or insurance companies and so will result in a return visit and additional charges will apply.


The Scope of a periodic inspection is a detailed description outlining which parts of the electrical installation are included in the EICR. For domestic properties with a single electrical supply periodic inspection typically covers the full electrical installation. For properties with multiple supplies or large installations it is common to split the installation and carry out a separate periodic inspection on each part. Separate inspections can be scheduled throughout the year to minimise disruption.

Frequency of periodic inspections

The following table offers merely a starting point for the electrical engineer to assess the maximum period between inspections and testing. The inspection frequency specified on your EICR may be more or less frequent than tabulated below.

#Type of InstallationRoutine CheckSuggested period between Inspection and Test (maximum of)Notes
1Domestic accommodation - general-Change of occupancy or 5 years1
2Rented domestic accommodation (houses, flats)1 yearChange of occupancy or 5 years2
3Residential accommodation (HMO)1 yearChange of occupancy or 5 years2
4Commercial (unless Special Location)1 yearChange of occupancy or 5 years3
5Industrial (unless Special Location)1 year3 years3
  1. We believe that for the vast majority of domestic installations, the maximum period between inspection and testing of 10 years (as specified in GN3, IET 18 ed.) is inadequate. This IET recommendation has remained unchanged for years, (at least going back to the 15th ed. of BS7671). It is now not uncommon for homes to undergo much more frequent alterations by various trades which can render the existing installation not fit for purpose. Furthermore, they types of devices now commonplace within the fixed wiring did not exist 10 years ago. I am of course referring to LED lighting, ELV transformers within the building fabric, USB or network sockets, Smart devices to name but a few. The guarantees provided by the manufacturer on such devices rarely go beyond three years!
  2. Of particular focus when undertaking inspections in rental properties is the intake equipment. This comprises the distributors cut-out and the electricity meter, ensuring that they are in a safe condition for continued operation and have not been tampered with. Ref: Electrical Safety, Quality and Continuity Regulations.
  3. Electricity at Work Regulations 1989.

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