NSW Electrical Licence key terms

The fixed relationship in a resistive circuit where voltage equals current multiplied by resistance, so any one value can be calculated when the other two are known.

The total opposition a circuit presents to alternating current, combining resistance with reactance so that current and voltage may not peak together.

The ratio of real power to apparent power in an AC circuit, indicating how effectively current is being converted into useful work.

The product of root-mean-square voltage and current in an AC circuit, measured in volt-amperes and including both real and reactive components.

The reduction in voltage along a conductor caused by its resistance and current flow, which must be limited so equipment receives adequate voltage.

An AC supply using three conductors whose voltages are displaced by 120 electrical degrees, allowing efficient motor operation and balanced loading.

Two ways of connecting three-phase windings or loads, one giving higher voltage at lower current and the other lower voltage at higher current.

The order in which the three phase voltages reach their peaks, which determines the direction of rotation of three-phase motors.

The maximum continuous current a conductor can carry under stated installation conditions without exceeding its rated temperature, after applying correction factors.

A multiplier applied to a cable's tabulated current rating to account for conditions such as ambient temperature, grouping, or thermal insulation.

A reduced current rating applied when a cable is surrounded by thermal insulation, since heat cannot escape as readily and the conductor runs hotter.

The way a cable is fixed, buried, enclosed, or supported, which determines how effectively heat is dissipated and which current rating table applies.

Connecting conductive parts together so they sit at substantially the same potential, reducing the risk of shock between simultaneously accessible surfaces.

The designated bar or link in an installation where protective earth conductors, the earthing conductor, and bonding conductors are connected together.

Connecting exposed conductive parts of equipment to earth so that fault current flows and a protective device operates quickly to disconnect supply.

The total impedance of the path taken by fault current from the source through the fault and back, which must be low enough for prompt disconnection.

The current that would flow at a point in an installation if a short circuit or low-impedance fault occurred there, used to select protective devices.

A protective device that continuously compares currents in active and neutral conductors and trips when an imbalance indicates current leaking to earth.

An automatically operated switch that opens a circuit on overload or short circuit and can be reset once the fault is corrected.

A protective device containing a element that melts and opens the circuit when current exceeds its rating for a set time.

A condition where current exceeds the normal operating value without a fault, and if sustained will overheat conductors and equipment.

A construction where live parts are separated from accessible surfaces by both basic insulation and an additional independent layer of insulation.

Equipment that relies on basic insulation plus a protective earth connection to its exposed metal parts for protection against electric shock.

A two-digit code describing how well an enclosure resists entry of solid objects and water, guiding suitability for a given environment.

Disconnecting all active conductors from supply and securing the disconnection so work can proceed without the risk of re-energisation.

Confirming a circuit is de-energised using a tester that has been checked before and after the test to prove it is functioning.

A check that a conductive path is intact and has low resistance, commonly used for protective earth conductors and bonding connections.

A measurement applying a high DC voltage between conductors and earth to confirm insulation is sound and free of moisture or damage.

A verification that active, neutral, and protective earth conductors are connected to the correct terminals throughout an installation.

A procedure using locks and warning tags on isolation points so a circuit cannot be re-energised while work is in progress.

A structured process of identifying hazards, evaluating the likelihood and severity of harm, and deciding on controls before work begins.

An ordered set of risk controls starting with eliminating the hazard, then substituting, engineering, administrative measures, and finally personal protective equipment.

Clothing and equipment worn by a worker, such as gloves, eye protection, and insulated tools, as a last line of defence against hazards.

The minimum distance a person or conductive object must keep from exposed live parts to avoid arc or contact hazards.

The authorisation issued by the regulator permitting a person to carry out electrical wiring work within defined scope and conditions.

A document completed by the licensed worker declaring that electrical work has been carried out and tested in accordance with requirements.

The oversight a licensed electrical worker provides to less qualified persons, remaining responsible for the quality and safety of the work.

The set of verification checks and measurements performed on completed work to confirm it meets the wiring rules before being placed in service.