How to Do Electrical Inspection and Testing

How to Carry Out Electrical Inspection and Testing

Electrical inspection and testing ensure installations remain safe and comply with regulations. You must perform them correctly to protect people, property, and equipment. There are two main types of inspections: Initial Verification and Periodic Inspection and Testing.

General Principles of Electrical Inspection

Only a skilled and competent person should carry out inspections. Competence means proper education, training, and practical skills to identify and avoid electrical hazards.

Before inspection, the verifier needs key information:

• Fundamental principles of BS 7671 (Chapter 13).

• General characteristics of the installation (Parts 311, 312, 313 of BS 7671).

• Diagrams, charts, or similar details (Regulation 514.9.1).

You must always follow safety precautions. Use safe isolation procedures before working on live parts to prevent harm or damage.

1. Initial Verification in Electrical Inspection and Testing

Initial verification applies to new electrical installations and to additions or alterations in existing systems.

The process has three steps:

The inspection comes before testing. Disconnect the installation from supply first. The visual check confirms that:

• • Equipment complies with standards.

  • Devices are correctly selected and installed.

  • No part shows visible damage.

Inspectors must check connections, conductor identification, cable routing, protection against damage, fire barriers, methods of shock protection, segregation of circuits, access to switchgear, and warning notices.

2. Testing Procedures for Electrical Inspection and Testing

Testing follows a preferred sequence. Use suitable instruments for each test. The main tests include:

• • Continuity of protective conductors.

  • Continuity of ring final circuit conductors.

  • Insulation resistance between live conductors and between live and earth.

  • Protection by barriers or enclosures.

  • Polarity of fuses, switches, and lamp holders.

  • Earth electrode resistance (for TT systems).

  • Earth fault loop impedance (Zs and Ze).

  • RCD effectiveness and trip times.

  • Prospective fault current (PFC/PSCC).

  • Phase sequence for polyphase systems.

  • Functional testing of switchgear, controls, and interlocks.

  • Voltage drop calculation or measurement (optional at this stage).

3. Certification After Electrical Inspection and Testing

Once complete, issue an Electrical Installation Certificate (EIC) for new installations or significant changes. For minor work without new circuits, issue a Minor Electrical Installation Works Certificate (MEIWC). Attach schedules of inspections and test results. Fix all defects before issuing certificates.

Periodic Electrical Inspection and Testing

Periodic inspection applies to existing installations. The goal is to confirm that the system remains safe for use.

When to Carry Out Periodic Electrical Inspection and Testing

You need a periodic inspection when:

• The previous inspection’s recommended interval expires.

• Insurance, mortgage, or licence conditions require it.

• Ownership or use of premises changes.

• Additions or alterations take place.

• The installation suffers damage or new loads are added.

What Inspectors Check

Inspectors review safety, age, corrosion, overloading, wear, external influences, and suitability. The scope must be agreed with the client, especially where wiring is concealed. Sampling may reduce the need for full dismantling. The focus is reporting, not fault finding.

Tests are usually the same as for initial verification. The sequence is flexible, but the initial verification order is preferred. In some cases, insulation resistance testing may be skipped if monitoring devices are in place and working.

Documentation and Reporting

After inspection, issue an Electrical Installation Condition Report (EICR) with inspection and test results. The report categorises observations:

• C1: Danger present.

• C2: Potentially dangerous.

• C3: Improvement recommended.

• FI: Further investigation needed.

An installation with C1 or C2 is classified as unsatisfactory. The report also states the next recommended inspection interval.

Standards and Regulations for Electrical Inspection and Testing

Electrical inspections in the UK must follow statutory and non-statutory standards:

• BS 7671:2018 (IET Wiring Regulations) for technical requirements.

• Electricity at Work Regulations 1989 (EAWR) for workplace electrical systems.

• Building Regulations Part P for domestic installations.

• Electricity Safety, Quality and Continuity Regulations (ESQCR) for suppliers.

• IET Guidance Note 3 (GN3) for inspection and testing guidance.

• HSE Guidance Note GS 38 for instrument and test lead requirements.

Why Electrical Inspection and Testing Matter

Electrical inspection and testing require strict procedures and skilled professionals. By following BS 7671 and related regulations, you can confirm safety, identify risks, and maintain compliance. Always document the process and act on any defects without delay.