The C&G 2391 2391 Practical Exam - Periodic Inspection

In this guide the qualification we are covering is the C&G 2391-52 Level 3 Award in Initial and Periodic Inspection and Testing of Electrical Installations, which is the combined, full Inspection and Testing qualification.

The practical exam required for this qualification is broken into two separate parts:
- Initial Verification of a brand new installation
- Periodic Inspection of an existing installation.

On this page, we are covering the second part - Periodic Inspection and everything that is associated with that part of the practical exam.

This part of the practical exam consists of two tasks:
1. Visual inspection
2. Periodic Inspection and Testing with the completion of the Electrical Installation Condition Report

Visual Inspection

The installation consists of only a few demo circuits and of a single phase consumer unit.

Within 30 minutes the delegate will be required to visually identify 12 faults/non compliments with BS 7671.

The faults can be some of these, but the list is far from complete:

• Incorrect polarity
• Exposed live parts
• Wrong choice of circuit breakers
• Wrong circuit arrangements inside the consumer unit (Neutrals and Earths not in order in their respective terminal bars)
• Wrong choice of colour coding
• Missing earth
• Twisted cables
• Missing protective bonding conductor
• Missing danger notices or other warning notices
• Incorrect or missing labelling of protective devices, switches and terminals
• Wrong selection of conductors for current-carrying capacity
• Connection of conductors (exposed copper)
• Physical damage to accessories
• Missing earth sleeving
• Loose SWA cleats
• Missing identification of switch wires

Remember this is a visual inspection only! You are expected to find faults without the use of hands or other methods.

Periodic Inspection & Testing

In the final part of the C&G 2391 practical assessment the delegate will be required to perform a full Inspection & Testing procedure on a sample electrical installation. The term "full" indicates that the inspection must cover 100% of the electrical installation. Sampling is allowed in "real life" conditions, but not on the C&G 2391 exam.

The given time is 120 minutes for this task.

The delegate will be presented with a sample electrical installation consisting of:

- 3 Phase&Neutral board supplying:

• 3 phase motor supply in SWA cable (DOL starter, no motor connected)
• Sockets supplied by a ring circuit
• Radial circuit to a FCU with MI cable
• Sub-main supply to the single phase consumer unit

- Single Phase&Neutral consumer unit supplying:

• Lighting circuit with intermediate switching
• Lighting circuit with a dimmer switch
• Socket outlet supplied by a radial circuit.

Before anything else the delegate will be expected to perform a Safe Isolation Procedure.

The sequence of the inspection and testing is as follows:

• Assessment of general characteristics
• Continuity of protective conductors, including p rotective bonding
• Continuity of ring final circuit conductors
• Polarity dead tests
• Insulation resistance test
• Polarity live tests
• Earth fault loop impedance tests
• Prospective fault current test
• Phase sequence test
• RCD test
• Functional testing

The delegate will be expected to perform a 100% correct inspection and testing procedure in the correct sequence.

It is very important to remember that as part of the C&G 2391 practical assessment the extent of the installation to be inspected is 100%! The delegate will be expected to inspect the installation during the testing process for faults and signs of damage within the installation. To do a thorough inspection the delegate will be expected to remove all lids and covers so as to gain visual access to parts of the electrical installation.

Individual items to be inspected:

• Joints and connection
• Conductors
• Flexible cables and cords
• Accessories and switchgear
• Thermal effects
• Basic and fault protection
• Protective devices
• Enclosures and mechanical protection
• Marking and labelling

Any faults or damages found must be reported to the examiner and recorded on the Electrica Installation Condition Report.

On our next pages we will cover each of the tests in full detail.