HK Grade B Electrical Worker Exam study plan

Classify the common Hong Kong wiring systems (surface conduit, concealed conduit, trunking, cable tray, MICC, armoured, flexible cord) and state where each is permitted or restricted under the Wiring Regulations (BS 7671 as applied in HK) and the Electricity Ordinance (Cap. 406) and its subsidiary regulations

Calculate current-carrying capacity for a given cable size, installation method (enclosed in conduit in thermally insulating wall, clipped direct, on tray, buried), ambient temperature and grouping, applying correction factors Ca, Cg, Ci and Ci

Determine the minimum cross-sectional area of earthing and protective conductors from the phase conductor size using the tabulated rule and verify with the adiabatic equation for a stated fault current and disconnection time

Distinguish the statutory duties of the registered electrical worker (Grade B) from the contractor's duties under the Electricity (Wiring) Regulations, including who may design, install, inspect, test and certify

Produce a one-page decision flowchart from load current to final selected cable size, showing every correction factor applied in order

Select wiring enclosures and support methods for a given environment (corrosive, damp, high-temperature, exposed to mechanical damage) and justify the choice against the relevant code requirements

Explain the TN-S, TN-C-S and TT supply arrangements as found in Hong Kong installations and identify the earthing arrangement from a described supply intake

Size main protective bonding conductors for water, gas and structural metalwork and state the locations where bonding is mandatory versus supplementary

Describe the requirements for earthing the consumer's installation, including earth electrode resistance expectations for TT systems and the role of the residual current device

Calculate voltage drop for a single-phase and a three-phase circuit and confirm compliance with the 3% lighting and 5% other-uses limits used in design

Design final circuits for lighting, socket outlets (ring and radial), immersion heater, cooker and air-conditioner loads, choosing protective device type and rating to protect the cable and the load

Assess maximum demand for a dwelling and a small shop using diversity allowances, and produce a load schedule with connected load, diversity factor and design current

Select MCB, MCCB, RCBO and fuse types by tripping characteristic and explain discrimination between upstream and downstream devices

State the requirements for RCD protection (30 mA for socket outlets and locations with increased shock risk), and explain the difference between RCD, RCBO and isolated RCBO arrangements

Verify that protective conductor disconnection times are met for a 220 V single-phase and 380 V three-phase final circuit using the relevant maximum earth fault loop impedance values

Sequence the inspection and testing process: visual inspection, continuity of protective and bonding conductors, ring final circuit continuity, insulation resistance, polarity, earth electrode resistance, earth fault loop impedance, RCD operation and functional testing

State the test instrument, expected reading and pass criterion for each of the tests above on a 220 V single-phase installation

Interpret insulation resistance results and explain why a reading below 1 megohm requires investigation before energisation

Identify the certificates and reports required under the Electricity (Wiring) Regulations and explain the role of the Work Completion Certificate and periodic inspection

Diagnose five typical faults (open circuit CPC, reversed polarity, high Zs, nuisance RCD tripping, borrowed neutral) from given test readings and state the remedy

Solve DC and single-phase AC series-parallel circuits for current, voltage, impedance, phase angle and power, including power factor correction by capacitor

Explain the operation of a three-phase induction motor, including slip, synchronous speed, star-delta starting and direct-on-line starting, and select a starter for a given load

Describe the protective functions for motors: overload relay, short-circuit protection, phase failure and undervoltage, and set an overload relay from nameplate full-load current

Explain transformer principles, turns ratio, losses and the reason for isolating transformers in special locations

Read and explain a simple motor control circuit with start, stop, emergency stop, contactor and interlock, and trace the circuit to identify why the motor will not start

Apply the zone rules for bathrooms (zones 0, 1, 2 and outside zones) and state permitted equipment IP ratings and the supplementary bonding requirements

State the requirements for construction site installations: reduced voltage for hand-held tools, RCD protection, isolation and the inspection regime for temporary supplies

Classify a hazardous area by zone and gas group and select equipment by explosion protection concept (flameproof, increased safety, intrinsic safety) appropriate to the zone

Specify protection and isolation requirements for swimming pools, saunas and agricultural locations where water and livestock increase risk

Explain the role of emergency lighting, fire alarm supply and escape route circuits in special locations and the requirement for independent isolation

Consolidate the statutory framework: Electricity Ordinance, Electricity (Wiring) Regulations, Electricity (Registration) Regulations and the Code of Practice for the Electricity (Wiring) Regulations, and state which document governs which activity

Re-derive the key design checks (cable capacity, voltage drop, disconnection time, RCD selection) from memory using the tabulated data

Work through timed mixed calculation sets combining demand assessment, cable sizing and earth fault loop impedance

Review inspection and testing procedures and practise writing a defect report in the style expected by an examiner

Identify your three weakest topics from practice results and build a targeted revision list for week 8

Review the full syllabus against a checklist and confirm every domain has been covered at least once with worked examples

Re-test the weak topics identified in week 7 and confirm improvement with a second timed mock

Practise explaining statutory and earthing answers aloud in short structured form (requirement, reference, application) to build exam recall

Rehearse the calculation set that most often loses marks: correction factors, voltage drop, Zs and RCD disconnection time

Finalise an exam-day plan covering time allocation per section and the order in which to attempt questions