This unit of competency has been developed for Engineering Tradesperson – industrial electrician apprenticeship training, and the recognition of trade-level skills in selecting cables for electrical installation work and equipment in areas including consumer mains, submains and final subcircuits for operating voltages up to 1000 V alternating current (AC) or 1500 V direct current (DC).

It covers a comprehensive understanding of the cable selection process of AS/NZS 3000:2007 Electrical Installations (known as the Australian/New Zealand Wiring Rules) and cable selection standards in determining maximum demand, voltage drop limitations, current carrying capacity and short circuit capability.

This unit covers the skills and knowledge required to meet the Electrical Regulatory Authorities Council (ERAC).

Essential Performance Capabilities (EPCs) classified as ‘critical’:

EPC 21 – Demonstrate the ability to select cables for mains and submains using AS/NZS 3000 and AS/NZS 3008.1 based on current carrying capacity, short circuit capability, maximum demand and voltage drop, for single phase and three phase installations including multiple installations.

EPC 22 – Demonstrate the ability to select cables for final subcircuits using AS/NZS 3000 and AS/NZS 3008.1 based on current carrying capacity, short circuit capability, maximum demand, earth loop impedance and voltage drop.

EPC 27 – Demonstrate knowledge of AS/NZS 3000 and local regulatory requirements for the installation of aerial conductors and underground wiring. Including specialist cables.

Some jurisdictions require the holder of this unit to be licensed or certified and users should check with the relevant authorities.

Band: A

Unit Weight: 4

Evidence required to demonstrate competence in this unit must be relevant to and satisfy the requirements of the elements and performance criteria on at least two (2) occasions and include:

following work instructions, standard operating procedures (SOPs) and safe work practices

identifying and interpreting circuits, drawings, plans and specifications relevant to the work to be undertaken

determining the cable routes, length and conditions in which the wiring system is to operate

complying with relevant Australian/New Zealand Wiring Rules, Cable Selection and Service Rules when selecting cables ensuring coordination between protective devices and conductors in regard to the following aspects:

design of the circuit taking into account the safety considerations

determining the final subcircuit arrangements

determining the factors affecting suitability of wiring systems

calculating the maximum demand on consumer mains/submains

calculating the current-carrying capacity requirements

calculating the voltage drop requirements

calculating the expected fault loop impedance

selecting cables to satisfy voltage drop, current-carrying capacity and fault loop impedance requirements

selecting the appropriate protection devices

selecting the appropriate isolation devices and switching arrangements

selecting earthing system parts to meet the multiple earthed neutral (MEN) system

documenting reasons for selection and installation requirements in accordance with SOPs.

Evidence required to demonstrate the required knowledge for this unit must be relevant to and satisfy the requirements of the elements and performance criteria and include knowledge of:

safe work practices and procedures and use of personal protective equipment (PPE)

Australian/New Zealand Wiring Rules, AS/NZS 3008.1.1:2009 Electrical Installations – Selection of cables – Cables for alternating voltages up to and including 0.6/1 kV – typical Australian installation conditions and other related standards in regards to the following:

design and safety performance requirements, including:

protection of persons, livestock and property from harmful effects

correct functioning of the electrical installation for intended use

compatibility with the electricity distribution system, or other source of supply, to which the electrical installation is to be connected

type of insulation required:

thermoplastic

elastomer

cross-linked polyethylene (XLPE)

mineral-insulated metal sheath (MIMS)

high temperature

supply characteristics

reasons for dividing installations into circuits and factors that determine their number and type

external influences that may damage installation and be considered in the design, including applying derating factors caused by the effect of:

grouping of cables

ambient temperature

depth of laying

thermal resistivity of soil

varying of loads

thermal insulation

direct sunlight

acceptable methods of protection against risks of ignition of flammable materials

likely sources of unwanted voltages and methods of dealing with this potential hazard

requirements for protection against fault current

protection against harmful effects of faults between live parts of circuits supplied at different voltages

mechanical movement protection

fire rated construction and how integrity of fire rating can be maintained

final subcircuit arrangements, including:

factors to consider when determining the number and type of circuits required

daily and seasonal demand for lighting, power, heating and other loads in a given installation

factors affecting current-carrying capacity of cables

layout/schedule of circuits

factors affecting suitability of wiring systems

acceptable methods of determining maximum demand on an installation’s consumer’s mains and submains up to 400 A per phase

external factors that require the use of a derating factor when determining current-carrying capacity

requirements for maximum voltage drop in an installation and relevant tables for unit values of voltage drop

requirements for maximum fault loop impedance in an installation and the relevant tables to determine cable impedances

accepted methods used against indirect contact when selecting protection devices to protect against overload and short circuit current situations

provision of isolation of every circuit for a range of installations and conditions

earthing system parts including the selection of earth electrode, main earthing conductor, main earthing terminal/connection or bar, MEN link, protective earthing conductors and equipotential bonding

effects of harmonic current on current-carrying capacity

conditions where short circuit performance may need to be considered.

Assessors must:

have vocational competency in selecting cable types and sizes to suit loads and electrical installation environment at least to the level being assessed with relevant industry knowledge and experience

satisfy the assessor requirements in the Standards for Registered Training Organisations 2015 and comply with the National Vocational Education and Training Regulator Act 2011 or equivalent legislation covering VET regulation in a non-referring State as the case requires.

Where possible assessment must occur in operational workplace situations. Where this is not possible or where personal safety or environmental damage are limiting factors, assessment must occur in a sufficiently rigorous simulated environment that reflects realistic operational workplace conditions. This must cover all aspects of workplace performance, including environment, task skills, task management skills, contingency management skills and job role environment skills.

Conditions for assessment must include access to all tools, equipment, materials and documentation required, including relevant workplace procedures, product and manufacturing specifications.

Assessment processes and techniques must be appropriate to the language, literacy and numeracy requirements of the work being performed and the needs of the candidate.

This section describes those required skills (reading, writing, oral communication and numeracy) that are essential to workplace performance in this unit of competency.

Foundation skills essential to performance are explicit in the performance criteria of this unit of competency.

Installation and commissioning