2391-101 Inspection, Testing and Certification of Electrical Installations

City & Guilds 2391: Level 3 Certificate in Inspection, Testing and Certification of
Electrical Installations

This course is aimed at those with practical experience of inspection and testing of LV electrical installations, who require to become certificated as an Approved Contractor.
Course objectives:

This course covers the theory and practice of the inspection, testing and certification of electrical installations and provides full preparation for City & Guilds 2391 written and practical assessments. The National Inspection Council for Electrical Installation Contracting (NICEIC) recommends that all Qualified Supervisors and operatives having direct responsibility for or being involved in inspection and testing should gain the 2391 Certificate.

However, the course is open to anyone having a good working knowledge of BS 7671 and current practical experience of inspection and testing of low voltage installations. It is not suitable for beginners.

The course embraces:

Statutory duties and safe working practices

BS 7671 requirements for inspection, testing and certification

IEE Guidance Note Number 3, Inspection & Testing, 4th edition, guidance and recommendations

Demonstration of tests and “hands-on” experience

Preparation for practical and written assessments

By the end of the course participants should be fully aware of:

The BS 7671 requirements for initial verification and periodic inspection and testing

The information required to correctly conduct the inspection and testing of an installation

The statutory and non-statutory requirements and relevant guidance material, which apply to the activity of inspecting and testing of electrical installations

The information to be contained on forms, i.e. Certificates, Periodic Inspection Reports, etc., and how this information should be recorded.

Participants should also be fully prepared for the practical and written assessments City & Guilds 2391-001/002.

Note: The course material provided should not be construed as having legal status.
It may, however, be used to assist responsible duty holders in creating a regime for the inspection, testing and certification of electrical installations.

The following objectives indicate the level of skills and knowledge required for this assessment.

The assessments assume the following abilities: to apply standard electrical formulae a detailed working knowledge of BS 7671 to carry out relevant calculations

 

Practical Activities

The candidate will be able to

Select the correct instruments and appropriate scales to carry out tests

Check and prove instruments and leads for safety and function

Given the information required, carry out an inspection and testing of an installation to the requirements of the current edition B2 7671

Complete an initial verification report, as given in Guidance Note 2, for the installation in item 3, including the schedule of test results

Carry out an inspection of installation components and record the deviations and complete a schedule of inspection.

 

Underpinning Knowledge

Outcome 1: Preparation for inspection and testing

The candidate will be able to

State the requirements for initial verification and periodic inspection and testing

State the information required to correctly conduct the inspection and testing of an installation

State the statutory and non-statutory requirements and relevant guidance material that apply to the activity of inspecting and testing of electrical installations

State the need to comply with statutory and non-statutory requirements, and guidance material for particular locations and environments in which electrical installations are installed

State the essential and optional information to be contained on Certificates and Inspection Reports and how the information is recorded on all certificates as indicated on the Guidance Note 3.

Outcome 2 : Inspection

The candidate will be able to

State the human sense that may need to be employed during the inspection of an installation

Refer to and select the items to be checked during the inspection process for given systems and locations as detailed in BS 7671 (current edition) 712

State the particular requirements for a periodic inspection of an electrical installation as defined in BS 7671 (current edition) 731

State the need to establish the extent and limitation of a Periodic Inspection Report, with the client, prior to commencing the inspection, and the need to record these details on the Periodic Report Form

State the requirements of the Electricity at Work Regulations for safe inspection and testing in terms of those carrying out the work using the installation and building during the inspection and testing.

State the need for instruments to be regularly checked and the need for their compliance with the requirements of BS 7617 (current edition) and HSE document GS 38

List the correct instruments and appropriate scale to carry out each test and explain the reasons for each choice

 

Outcome 3 : Testing

For each topic the candidate will be able to

Instruments

State the need for instruments to be regularly checked and the need for their compliance with the requirements of BS 7617 (current edition) and HSE document GS 38

List the correct instruments and appropriate scale to carry out each test and explain the reasons for each choice

 

Sequence

State the recommended sequence of tests and the reasons for that sequence

 

Protective Conductors

State the requirements which need to be considered for protective conductors in the terms of

earthing conductors

main equipotential bonding conductors

supplementary equipotential bonding conductors

circuit protective conductors

Describe the need for and methods of verifying the continuity of protective conductors and the interpretation of results

State the relationship between conductor length, csa and resistance

State the effect of the temperature on a conductor

 

Ring Circuits

State the effect on resistance when cables are connected in parallel

Describe the need for and methods for verifying the continuity of ring final circuit conductors and the interpretation of results.

 

Insulation Resistance

Explain, by example, the effect on insulation resistance of cables connected in parallel variation in cable length

Compare the difference between measurements taken for insulation resistance and conductor resistance, stating the order of magnitude that would be expected in each case

State the relationship between conductor length and conductor resistance

State the preconditions required for the performance of insulation testing

State the precautions to be taken before testing insulation resistance

Describe methods of testing insulation resistance

State the required test voltages and minimum values or insulation resistance for circuits operation at various voltages

 

Site Applied Insulation

State the requirements for penetration tests and flashover tests on site applied insulation

 

Electrical Separation

Describe the tests to verify the electrical separation of SELV circuits

State the particular requirements for protection by electrical separation (NOT SELV)

 

Special Installations and Locations

State the requirements for circuits in prescribed special installations and locations, in terms of identifying the installations and locations to which special requirements apply

Demonstrate the ability to make reference to the appropriate requirements in each case from given information be able to identify the requirements in relation to specific areas and installations

 

IP Code

State the appropriate degrees of protection required for given locations and environments afforded within the IP classification BS 605229

 

Polarity

Describe the need for and methods of testing used to identify correct polarity

 

Earth Electrodes

Differentiate between the requirements for testing of earth electrodes for RCD protected TT systems and electrodes for transformers and generators

 

Earth Fault Loop Impedance

Describe the earth fault loop impedance paths for the following systems

TN-S

TN-C-S

TT

Describe methods of determining earth fault loop impedance in terms of the tests used for measuring actual earth fault – loop impedance methods of calculation of earth fault loop impedance from given data and measurement of conductor impedance

Given maximum tabulated values of earth fault loop impedance, verify that measured values are acceptable, taking into account conductor operating and ambient temperatures

 

Residual Current Devices (RCDs/RCBO's)

Describe methods of testing the correct operation of RCD's, independent of in-built test facilities
State the applications for various RCD ratings

 

Prospective Fault Current

Describe methods of determining prospective fault current in terms of prospective short circuit current prospective earth fault current
Explain the importance of selecting protective devices appropriate to the prospective fault current

 

2391 – 102 Practical Assessments

The test rig and inspection and testing equipment

To carry out these inspections and testing practical assessments, simulated installations should be constructed in accordance with the diagrams given the Assessment Guide for Centres.

The test rigs should be located in an area of adequate space and light. All connections must be directly to the accessories, rather than simulated, and allowance should be made for the replacement of connections as they become worn.

 

The test equipment provided by the centre must meet the requirements of BS 7671 and HSE document GS 38

To ensure that the candidate has to make a selection from the equipment provided, there should be a greater range of test instruments available than is actually required to carry out the tests.

The test instruments for Assessment 4 must include a voltage indicator, with the necessary proving equipment, to test for correct isolation.

To simulate ‘real' conditions the test rig must be connected to a 400V three-phase and neutral supply.

 

Test Procedure

The candidate should be given the appropriate results sheet for the assessment a selection of hand tools where required, to carry out the test of installation a range of test instruments including those required to complete the tests.

Candidate identification and other relevant information should be completed on the appropriate result sheet prior to the commencement of each test.

The candidate will be expected to record all relevant information and test results for all circuits on the appropriate results sheet.

 

The tests and performance criteria for assessment

The tests that must be completed and the detailed performance criteria the candidate must meet in order to pass the test are provided in the Assessment Guide for Centres.   A copy of each set of performance criteria must be completed for each candidate

Consideration should be given to the Electricity at Work Regulations throughout the assessment process, and it should be made clear to the candidate that failure to observe appropriate safe working practices will result in the assessment being stopped

 

Inspection and Testing

Practical Activities

The candidate will be able to

Conduct an initial inspection meeting all relevant Safety Legislation and the Requirements of BS 7671.

 

Underpinning Knowledge

The candidate will be able to

Identify the four human senses that may be utilised during the inspection process

State the need to avoid danger to persons damage to property and installed equipment

Verify that installed electrical equipment is in compliance with British or Harmonised Standards meets design parameters and the requirements of BS 7671 is not damaged or defective

Identify the inspection check list in BS 7671 (items i to xvii) and apply those that are relevant to a given electrical installation

Describe the purpose of a periodic inspection for an existing electrical installation

Recognise a schedule of inspections as being an essential part of the documentation required for either an initial verification or periodic inspection

Explain the need for protective conductors within an electrical installation

Describe methods of verifying the continuity of protective conductors

Describe approves methods of verifying the continuity of ring final circuit conductors

Carry out calculations from given test results to verify the continuity of ring final circuit conductors

State the precautions required prior to conducting insulation resistance testing

Describe the procedures and methods of conducting insulation resistance testing

State the required test voltages and minimum values of insulation resistance for conventional circuits

Describe penetration tests and flashover tests for site applied insulation

Describe tests to verify electrical separation of SELV circuits

Identify the requirements within BS 7671 for SELV circuits

State the special requirements for protection by electrical separation (NOT SELV) and describe tests to verify these

Describe the degrees of protection set out in the Index of Protection Codes for Enclosures (BSEN 60529) relevant to BS 7671

Describe approved methods of testing polarity both before and after a circuit or an installation has been energised

Describe approved methods of measuring earth electrode resistance

Describe approved methods of measuring earth fault loop impedance

Determine, for given criteria, suitable types and ratings of protective devices

Describe approved methods of measuring prospective fault current

Describe methods of testing residual current devices, independent of inbuilt test facilities

Explain the difference in the requirements for both initial and periodic inspection and test procedures

Describe the requirements of BS 7671 that are relevant to alterations and additions to an existing circuit or installation

Identify the range of notices that may be located within an installation

Understand the onerous responsibility associated with the completion of electrical installation certificates

periodic inspection reports

associated inspection and test schedules

minor electrical installation and test schedules

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