NSW Electrical Licence cheat sheet

Ohm's law: V = I × R; power P = V × I = I²R = V²/R, with V in volts, I in amperes, R in ohms, P in watts.

AC sine wave: RMS value = peak ÷ √2 (≈0.707 × peak); average value of a full sine wave is zero.

Impedance Z = √(R² + X²), where X is reactance in ohms; X_L = 2πfL and X_C = 1/(2πfC).

Three-phase power: P = √3 × V_L × I_L × cos φ for a balanced load, with V_L the line-to-line voltage.

Star connection: V_L = √3 × V_phase and I_L = I_phase; delta connection: V_L = V_phase and I_L = √3 × I_phase.

Conductor resistance R = ρL/A, so resistance rises with length and resistivity and falls as cross-sectional area increases.

Power factor = true power (W) ÷ apparent power (VA); a lagging power factor indicates an inductive load.

Series circuit: current is common, voltages add, R_total = R1 + R2 + …; parallel circuit: voltage is common, currents add.

Cable current-carrying capacity must be derated for ambient temperature, grouping, thermal insulation and installation method before comparing with load current.

Voltage drop limit for consumer mains and final subcircuits is conventionally 5% of nominal supply voltage from the point of supply.

Sheath colours: orange identifies circular cable, white identifies flat TPS; conductor colours are brown (active), blue (neutral), green/yellow (earth).

Cables in accessible roof spaces must be kept clear of walkways, fixed securely and protected where subject to mechanical damage.

Socket outlets in domestic premises require additional protection by a 30 mA RCD under AS/NZS 3000 requirements.

Minimum bending radius and support spacing are set by the cable manufacturer and AS/NZS 3000; supports are required at regular intervals.

Segregation: telecommunications and data cabling must be separated from low-voltage mains wiring by the prescribed clearance to limit induction.

Earth fault loop impedance Z_s = Z_external + Z_active + Z_protective earth; the measured value must allow the protective device to trip within the required time.

Maximum disconnection times under AS/NZS 3000: 0.4 s for final subcircuits up to 63 A, 5 s for distribution circuits and fixed equipment above 63 A.

An RCD with 30 mA rated residual current is required for socket outlets, lighting circuits in domestic installations and other prescribed circuits.

MEN system: the neutral is earthed at the point of supply and the protective earth is bonded to the neutral bar at the main switchboard.

Main earthing conductor size is determined by the active conductor cross-section per AS/NZS 3000 Table 5.1, not simply by load current.

Equipotential bonding connects metallic water, gas and structural services to the main earthing terminal to limit touch voltage.

Circuit breakers provide overload and short-circuit protection; RCDs provide additional protection against earth leakage and electric shock.

Equipment must be marked with its rated voltage, current or power, and be suitable for the supply and environment of installation.

Ingress protection code IPXY: first digit is protection against solids (0–6), second digit is protection against water (0–8).

Appliances supplied with a flexible cord must be connected via a plug and socket outlet or a fixed connection with a cord anchorage.

Class I equipment relies on basic insulation plus a protective earth; Class II equipment uses double or reinforced insulation and no earth.

Switchboards require a main switch, protective devices, a main earth bar and a neutral bar, with a legible diagram or schedule.

Motor circuits require overload protection, short-circuit protection and, where required, isolation and emergency stopping arrangements.

Socket outlets, switches and accessories must be installed so that live parts are not accessible and operation is not obstructed.

Verification sequence: visual inspection first, then continuity of protective earthing, insulation resistance, polarity, earth fault loop impedance and RCD operation.

Insulation resistance test at 500 V DC must give at least 1 MΩ for the installation, with sensitive equipment disconnected.

Continuity of the protective earthing conductor is confirmed by a low-resistance measurement from the main earth bar to each outlet earth.

Polarity testing confirms active and neutral are not reversed and that switches are in the active conductor.

RCD trip time test: the device must operate within 300 ms at rated residual current and must not trip at half rated residual current.

Earth fault loop impedance is measured at the farthest point of each circuit and compared with the maximum value for the protective device.

Live testing requires a voltage indicator proved before and after use on a known source, and fault finding follows a logical divide-and-test approach.

PCBUs must eliminate or minimise risks so far as is reasonably practicable, using the hierarchy of control from elimination to PPE.

De-energise, isolate, lock out and tag out before work; prove the circuit dead with a tested voltage indicator and test again after the work.

A safety observer is required for live work, and live work is only permitted where it is essential and the risk is controlled.

Personal protective equipment is the last line of defence: insulated gloves, safety glasses, arc-rated clothing and insulated tools.

Any electrical incident or near miss must be reported to the supervisor and recorded; notifiable incidents must be reported to the regulator.

Working at heights requires fall prevention, a stable ladder or platform, and exclusion zones below the work area.

Residual current devices, test-before-touch procedures and warning signs are administrative and engineering controls for electrical risk.

Electrical work in NSW must be carried out by or under the supervision of a licensed electrician, and the licence must be held by the individual.

A Certificate of Compliance for Electrical Work (CCEW) must be issued for prescribed electrical work and a copy given to the person for whom the work is done.

The CCEW must be sent to the network operator or regulator within the prescribed period, and records retained for the required period.

Only a licensed electrician may connect electrical installation work to the supply; the network operator authorises the connection.

Licence classes in NSW include electrician, qualified supervisor and contractor; a contractor licence is required to contract for electrical work.

AS/NZS 3000 (Wiring Rules) is the primary standard, supported by AS/NZS 3017 for verification and AS/NZS 4836 for safe work on low-voltage installations.

Continuing professional development and licence renewal are required; working outside the scope of the licence is an offence.

Ohm's law: V = I × R; power P = V × I = I²R = V²/R, with V in volts, I in amperes, R in ohms, P in watts.

AC sine wave: RMS value = peak ÷ √2 (≈0.707 × peak); average value of a full sine wave is zero.

Impedance Z = √(R² + X²), where X is reactance in ohms; X_L = 2πfL and X_C = 1/(2πfC).

Three-phase power: P = √3 × V_L × I_L × cos φ for a balanced load, with V_L the line-to-line voltage.

Star connection: V_L = √3 × V_phase and I_L = I_phase; delta connection: V_L = V_phase and I_L = √3 × I_phase.

Conductor resistance R = ρL/A, so resistance rises with length and resistivity and falls as cross-sectional area increases.

Power factor = true power (W) ÷ apparent power (VA); a lagging power factor indicates an inductive load.

Series circuit: current is common, voltages add, R_total = R1 + R2 + …; parallel circuit: voltage is common, currents add.

Cable current-carrying capacity must be derated for ambient temperature, grouping, thermal insulation and installation method before comparing with load current.

Voltage drop limit for consumer mains and final subcircuits is conventionally 5% of nominal supply voltage from the point of supply.

Sheath colours: orange identifies circular cable, white identifies flat TPS; conductor colours are brown (active), blue (neutral), green/yellow (earth).

Cables in accessible roof spaces must be kept clear of walkways, fixed securely and protected where subject to mechanical damage.

Socket outlets in domestic premises require additional protection by a 30 mA RCD under AS/NZS 3000 requirements.

Minimum bending radius and support spacing are set by the cable manufacturer and AS/NZS 3000; supports are required at regular intervals.

Segregation: telecommunications and data cabling must be separated from low-voltage mains wiring by the prescribed clearance to limit induction.

Earth fault loop impedance Z_s = Z_external + Z_active + Z_protective earth; the measured value must allow the protective device to trip within the required time.

Maximum disconnection times under AS/NZS 3000: 0.4 s for final subcircuits up to 63 A, 5 s for distribution circuits and fixed equipment above 63 A.

An RCD with 30 mA rated residual current is required for socket outlets, lighting circuits in domestic installations and other prescribed circuits.

MEN system: the neutral is earthed at the point of supply and the protective earth is bonded to the neutral bar at the main switchboard.

Main earthing conductor size is determined by the active conductor cross-section per AS/NZS 3000 Table 5.1, not simply by load current.

Equipotential bonding connects metallic water, gas and structural services to the main earthing terminal to limit touch voltage.

Circuit breakers provide overload and short-circuit protection; RCDs provide additional protection against earth leakage and electric shock.

Equipment must be marked with its rated voltage, current or power, and be suitable for the supply and environment of installation.

Ingress protection code IPXY: first digit is protection against solids (0–6), second digit is protection against water (0–8).

Appliances supplied with a flexible cord must be connected via a plug and socket outlet or a fixed connection with a cord anchorage.

Class I equipment relies on basic insulation plus a protective earth; Class II equipment uses double or reinforced insulation and no earth.

Switchboards require a main switch, protective devices, a main earth bar and a neutral bar, with a legible diagram or schedule.

Motor circuits require overload protection, short-circuit protection and, where required, isolation and emergency stopping arrangements.

Socket outlets, switches and accessories must be installed so that live parts are not accessible and operation is not obstructed.

Verification sequence: visual inspection first, then continuity of protective earthing, insulation resistance, polarity, earth fault loop impedance and RCD operation.

Insulation resistance test at 500 V DC must give at least 1 MΩ for the installation, with sensitive equipment disconnected.

Continuity of the protective earthing conductor is confirmed by a low-resistance measurement from the main earth bar to each outlet earth.

Polarity testing confirms active and neutral are not reversed and that switches are in the active conductor.

RCD trip time test: the device must operate within 300 ms at rated residual current and must not trip at half rated residual current.

Earth fault loop impedance is measured at the farthest point of each circuit and compared with the maximum value for the protective device.

Live testing requires a voltage indicator proved before and after use on a known source, and fault finding follows a logical divide-and-test approach.

PCBUs must eliminate or minimise risks so far as is reasonably practicable, using the hierarchy of control from elimination to PPE.

De-energise, isolate, lock out and tag out before work; prove the circuit dead with a tested voltage indicator and test again after the work.

A safety observer is required for live work, and live work is only permitted where it is essential and the risk is controlled.

Personal protective equipment is the last line of defence: insulated gloves, safety glasses, arc-rated clothing and insulated tools.

Any electrical incident or near miss must be reported to the supervisor and recorded; notifiable incidents must be reported to the regulator.

Working at heights requires fall prevention, a stable ladder or platform, and exclusion zones below the work area.

Residual current devices, test-before-touch procedures and warning signs are administrative and engineering controls for electrical risk.

Electrical work in NSW must be carried out by or under the supervision of a licensed electrician, and the licence must be held by the individual.

A Certificate of Compliance for Electrical Work (CCEW) must be issued for prescribed electrical work and a copy given to the person for whom the work is done.

The CCEW must be sent to the network operator or regulator within the prescribed period, and records retained for the required period.

Only a licensed electrician may connect electrical installation work to the supply; the network operator authorises the connection.

Licence classes in NSW include electrician, qualified supervisor and contractor; a contractor licence is required to contract for electrical work.

AS/NZS 3000 (Wiring Rules) is the primary standard, supported by AS/NZS 3017 for verification and AS/NZS 4836 for safe work on low-voltage installations.

Continuing professional development and licence renewal are required; working outside the scope of the licence is an offence.