Testing electrical equipment and circuits
Overview
This standard identifies the competences you need to carry out inspections and tests on electrical equipment, such as switchgear, wiring systems, power, heating and lighting systems, motors and motor drives, contactors and relays, control panels, sensors and actuators, and power electronic systems, in accordance with approved procedures. You will be required to carry out formal inspections and tests, which will include protective insulation and resistance values, load current, voltage levels and power ratings, on a range of electrical equipment, to establish that it is functioning at optimal level and to specification.
Your responsibilities will require you to comply with organisational policy and procedures for the testing activities undertaken, and to report any problems with these activities, or with the tools and equipment used that you cannot personally resolve or that are outside your permitted authority, to the relevant people. You will be expected to work with minimal supervision, taking personal responsibility for your own actions, and for the quality and accuracy of the work that you carry out.
Your underpinning knowledge will provide a sound understanding of your work, and will provide an informed approach to applying test procedures to electrical equipment and circuits. You will understand the equipment being worked on, the test equipment to be used, and the various test procedures, in adequate depth to provide a sound basis for carrying out the activities safely and correctly and ensuring that the equipment remains compliant with all standards and regulations. In addition, you will be expected to review the outcome of the tests, compare the results with appropriate standards, determine the action required, and to record and report the results in the appropriate format.
You will understand the safety precautions required when carrying out the inspection and testing activities, especially those for isolating the equipment and taking the necessary safeguards to protect yourself and others against direct and indirect electric shock. You will be required to demonstrate safe working practices throughout, and will understand the responsibility you owe to yourself and others in the workplace.
Performance criteria
You must be able to:
- work safely at all times, complying with health and safety legislation and other relevant regulations, directives and guidelines
- follow the appropriate procedures for use of tools and equipment to carry out the required tests
- set up and carry out the tests using the correct procedures and within agreed timescales
- complete and store all relevant documentation of the test outcome in accordance with organisational requirements
- review the results and carry out further tests if necessary
- dispose of waste materials in accordance with safe working practices and approved procedures and leave the work area in a safe condition
Knowledge and Understanding
You need to know and understand:
- the health and safety requirements of the work area where you are carrying out the testing activities, and the responsibility these requirements place on you
- the equipment isolation and lock-off procedure or permit-to-work procedure that applies to the testing activities (such as electrical isolation, locking off switchgear, removal of fuses, placing of maintenance warning notices, proving the isolation has been achieved and secured)
- the hazards associated with carrying out tests on electrical systems, and how to minimise these and reduce any risks
- the specific safety precautions to be taken when carrying out formal inspection and testing of electrical equipment
- how to recognise and deal with victims of electrical shock (to include methods of safely removing victim from the power source, isolating the power source) and the differences between AC and DC electric shock and how this affects the victim
- how to reduce the risks of a phase to earth shock (such as insulated tools, rubber matting and isolating transformers)
- the importance of wearing protective clothing and other appropriate safety equipment (PPE) during the electrical testing activities
- protection techniques for electrical systems (to prevent burn or fire risk)
- the precautions (such as use of wrist straps, special packaging and handling areas) to be taken to prevent electrostatic discharge (ESD) damage to circuits and components
- how to obtain and interpret drawings, circuit and physical layouts, charts, specifications, manufacturers' manuals, history/maintenance reports, graphical electrical symbols, wiring regulations, and other documents needed in the testing activities
- types of test equipment to be used, and their selection for particular types of tests
- how to ensure that the test equipment is maintained and correctly calibrated, in accordance with the appropriate organisational procedures
- how to connect the appropriate test equipment for the measurement of resistance, current, voltage, power, capacitance, inductance, frequency, power factor, and protective device disconnection/trip times
- the various testing methods and procedures, as recommended in approved electrical codes of practice, and how to apply them to different operating conditions
- displaying/recording test results, and the documentation to be used
- how to interpret the value and significance of the test readings
- how to analyse test results using tables in approved electrical codes of practice, and how to use comparison and sequential techniques
- the importance of ensuring that test equipment is used only for its intended purpose and within its specified range and limits
- problems or errors that may occur and which could affect the test results, and how they can be avoided
- the environmental control and organisational operating procedures relating to the testing activities
the documentation required and the procedures to be observed following the test
the extent of your own authority and to whom you should report if you have problems that you cannot resolve
Scope/range
Carry out all of the following during the testing activities:
- plan the inspection and testing activities to cause minimal disruption to normal working
- obtain and use the correct issue of organisational and/or manufacturers' drawings and maintenance documentation
- adhere to procedures or systems in place for risk assessment, COSHH, personal protective equipment and other relevant safety regulations and procedures to realise a safe system of work
- ensure the safe isolation of equipment
- provide and maintain safe access and working arrangements for the testing area
- carry out the inspection and testing activities using appropriate techniques and procedures
- re-connect and return the system to service on completion of the testing activities
- dispose of waste materials in accordance with safe working practices and approved procedures and leave the work area in a safe condition
Carry out inspections and tests on six of the following types of electrical equipment:
- distribution switchgear
- control panels
- sensors
- wiring systems
- programmable logic control (PLC) systems
- actuators
- electric motors
- power electronic systems
- power, heating and lighting systems
- contactors and relays
- accessories
- other specific electrical equipment
Use appropriate test equipment to carry out five of the following tests, as applicable to the equipment being maintained:
- protective conductor resistance values
- continuity
- RCD disconnection time
- polarity
- specialised tests (such as speed, sound, light, temperature)
- insulation resistance values
- power rating
- load current
- resistance
- voltage levels
- capacitance
- Impedance
- frequency values
Carry out all of the following checks to ensure the accuracy and quality of the tests carried out:
- the test equipment is correctly calibrated
- test equipment used is appropriate for the tests being carried out
- test procedures used are as recommended in the appropriate electrical codes of practice
- test equipment is operated within its specification range
Complete and store all relevant documentation of the test outcome in accordance with organisational requirements, using one of the following:
- preventative maintenance log/report
- inspection schedule
- organisational-specific reporting procedure
- specific test report
- electronic reporting system