Study for the C&G 2391-52 Online

The City & Guilds 2391-52, officially titled "Inspection, Testing and Certification of Electrical Installations," is the current industry-standard qualification for electricians who carry out inspection and testing of electrical installations in the United Kingdom. It replaced the earlier 2391-51 and, before that, the separate 2394 (Initial Verification) and 2395 (Periodic Inspection and Testing) qualifications.

The 2391-52 demonstrates that you have the knowledge and practical skills to carry out two distinct types of inspection and testing. The first is initial verification — the inspection and testing of new installations or alterations before they are energised and handed over to the client. The second is periodic inspection and testing — the assessment of existing installations that are already in service, to identify deterioration, damage, defects, and departures from the current edition of BS 7671:2018+A4:2026.

The qualification is essential for any electrician who wants to work independently and certify their own installations. Without the 2391-52 (or its predecessor equivalents), you cannot join a competent person scheme such as NICEIC, NAPIT, or ELECSA as a qualified supervisor. Without scheme membership, you cannot self-certify notifiable electrical work under Part P of the Building Regulations in England and Wales, meaning your clients would need to involve their local authority building control for every job — an additional cost and delay that most clients will not accept.

The 2391-52 also underpins your ability to issue Electrical Installation Certificates (EICs) for new work and Electrical Installation Condition Reports (EICRs) for periodic inspections. Since the Electrical Safety Standards in the Private Rented Sector (England) Regulations 2020 made five-yearly EICRs mandatory for all rented properties, the demand for qualified inspection and testing professionals has increased significantly. Holding the 2391-52 opens a lucrative revenue stream for self-employed electricians and small contractors. Before sitting the 2391-52, ensure you have completed the 18th Edition wiring regulations course.

The 2391-52 is relevant to several groups within the electrical industry. Understanding whether you need it helps you plan your career development and training investment effectively.

The 2391-52 assessment is divided into two components, both of which must be passed to achieve the full qualification. Understanding the structure and marking criteria gives you a significant advantage in your preparation.

Component 1: Written Examination. The written paper is an open-book examination (you may bring BS 7671 and GN3) lasting approximately two hours. It includes a mixture of multiple-choice questions and short-answer questions. Topics covered include safe isolation procedures and their regulatory basis (HSE Guidance Note GS 38 and the Electricity at Work Regulations 1989), the full GN3 testing sequence with rationale for the test order, BS 7671:2018+A4:2026 regulation references relevant to inspection and testing (particularly Chapter 61 for initial verification and Chapter 62 for periodic inspection), testing instrument selection, operation, and calibration requirements, documentation requirements for EICs, EICRs, Minor Electrical Installation Works Certificates, and Schedule of Inspections and Test Results, and observation code assignment and overall condition assessment.

Component 2: Practical Assessment. The practical assessment lasts approximately three to four hours and is carried out at an approved assessment centre. You are presented with one or two installations (one for initial verification, one for periodic inspection) and must carry out a thorough inspection and testing procedure, record your findings accurately, and produce the correct certification. Assessors evaluate your safe isolation technique, adherence to the GN3 testing sequence, accuracy of instrument readings, identification of defects, correct observation code assignment, and completeness of documentation.

The practical assessment is where many candidates struggle, often not because of a lack of knowledge but because of nerves, poor time management, or unfamiliarity with the documentation format. Elec-Mate addresses all three issues: the scenario walkthroughs build confidence through repetition, the timed practice sessions develop your pace, and the certificate practice forms ensure you can complete every section of every document without hesitation.

A clear understanding of the differences between initial verification and periodic inspection is fundamental to the 2391-52. While both involve inspection and testing, their purpose, scope, and documentation differ significantly.

Initial verification is carried out on new installations or alterations before they are energised and handed over to the client. It confirms that the installation has been designed, constructed, inspected, and tested in accordance with BS 7671:2018+A4:2026. The process includes a detailed visual inspection against the design documentation (checking cable types, containment, accessory ratings, protective device coordination, and general workmanship), followed by the full GN3 testing sequence. The documentation produced is an Electrical Installation Certificate (EIC), which includes the design, construction, and inspection and testing sections, plus a Schedule of Inspections and a Schedule of Test Results.

Periodic inspection and testing is carried out on existing installations that are already in service. Its purpose is to assess the condition of the installation by identifying any deterioration, damage, defects, or non-compliance with the current edition of BS 7671. This is particularly important because installations degrade over time — cable insulation deteriorates, connections become loose, accessories suffer wear, and previous alterations may not have been carried out competently. The process includes a visual inspection (as far as reasonably practicable without dismantling the installation beyond what is necessary), followed by testing, followed by the identification and coding of any observations. The documentation produced is an Electrical Installation Condition Report (EICR), which includes observation codes (C1, C2, C3, FI) and an overall condition assessment of Satisfactory or Unsatisfactory.

A key difference in the testing is that periodic inspection may involve testing circuits that are already in service, which requires careful planning to minimise disruption to the occupants. The extent and limitations of the inspection must be agreed with the client beforehand and documented on the EICR. Initial verification, by contrast, is always carried out before the installation is energised, giving the inspector full access to all circuits without concern about disruption.

If you are new to inspection and testing qualifications, the landscape of qualification numbers can be confusing. Here is a clear summary of how they relate to each other and which one you should pursue.

The C&G 2394 (Initial Verification of Electrical Installations) was a standalone qualification covering the inspection and testing of new installations before they were energised. It taught candidates how to carry out initial verification and complete Electrical Installation Certificates. It has been withdrawn and is no longer available to new candidates.

The C&G 2395 (Periodic Inspection and Testing of Electrical Installations) was the companion qualification covering the inspection and testing of existing installations already in service. It taught candidates how to carry out periodic inspections and complete Electrical Installation Condition Reports. Like the 2394, it has been withdrawn.

The C&G 2391-51 combined both areas into a single qualification. It was the transitional replacement for the 2394 and 2395.

The C&G 2391-52 is the current version, with enhanced emphasis on certification and documentation accuracy. It is the only version available to new candidates. If you hold both the 2394 and 2395, most scheme providers consider this equivalent to the 2391. However, if you only hold one of the pair, you should take the 2391-52 to cover both areas. All new candidates should take the 2391-52.