100+ Free HK Grade B Electrical Worker Exam Practice Questions

Pass your Examination for Registration as a Grade B Electrical Worker exam on the first try — instant access, no signup required.

✓ No registration✓ No credit card✓ No hidden fees✓ Start practicing immediately

100+ Questions

100% Free

Loading practice questions...

Same family resources

Explore More Hong Kong EMSD Electrical Worker Registration

Continue into nearby exams from the same family. Each card keeps practice questions, study guides, flashcards, videos, and articles in one place.

HK CIC Trade Test for Grade A Electrical Work

Practice Questions100 questions

HK EMSD Grade C Electrical Worker Registration Examination

Practice Questions100 questions

Sample HK Grade B Electrical Worker Exam Practice Questions

Try these sample questions to test your HK Grade B Electrical Worker Exam exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Under the Electricity Ordinance (Cap. 406), Grade B electrical work covers low-voltage fixed installations with maximum demand not exceeding:

A.400 A single or three phase

B.2,500 A

C.Any LV capacity

D.High-voltage installations only

Explanation: EMSD grading defines Grade B as LV fixed electrical installation work where maximum demand does not exceed 2,500 A. Grade A is limited to 400 A and Grade C covers any LV capacity.

2The HKEAA Grade B registration examination Part A consists of how many multiple-choice questions, and what is the pass mark?

A.50 questions at 70%

B.28 questions at 75%

C.72 questions at 50%

D.100 questions at 60%

Explanation: Official Grade B Part A is 28 MCQs with a 75% pass mark and no negative marking. Part B has 72 MCQs at 50%.

3For the Grade B registration examination Part B, the official pass requirement is:

A.75% with no negative marking

B.50% with no negative marking

C.70% with 0.25 mark deducted per wrong answer

D.60% with mandatory essay section

Explanation: Grade B Part B is 72 MCQs requiring 50% to pass, with no marks deducted for wrong answers. Candidates must pass both Part A and Part B.

4The total official Grade B registration examination (Part A plus Part B) contains:

A.50 MCQs in one sitting

B.100 MCQs over two parts

C.28 MCQs only

D.72 essay questions

Explanation: Grade B comprises Part A (28 MCQs) and Part B (72 MCQs), totalling 100 multiple-choice questions. The combined sitting is typically 2 hours, bilingual.

5The Code of Practice for the Electricity (Wiring) Regulations in Hong Kong is issued primarily to:

A.Replace the Electricity Ordinance as statute

B.Give technical guidance for complying with the Electricity (Wiring) Regulations

C.Set CLP Power tariff rates only

D.Certify CIC trade-test candidates automatically

Explanation: EMSD publishes the CoP as the principal technical guide for fixed electrical installations under Cap. 406 Wiring Regulations. It supports compliance but does not replace statute.

6Ohm's law for a purely resistive circuit states that voltage equals:

A.Current divided by resistance

B.Current multiplied by resistance

C.Resistance divided by current

D.Power multiplied by time

Explanation: V = IR is fundamental to circuit analysis in the Grade B syllabus. It links conductor heating, voltage drop and protective device coordination calculations.

7In a balanced three-phase star-connected load, the line voltage VL relates to phase voltage Vph by:

A.VL = Vph

B.VL = √3 × Vph

C.VL = 3 × Vph

D.VL = Vph / √3

Explanation: For star connection, line voltage is √3 times phase voltage. This relationship is essential when converting between line and phase values in 3-phase calculations.

8Kirchhoff's Current Law (KCL) at a node in an electrical network requires that:

A.The sum of voltage drops equals zero

B.The algebraic sum of currents entering and leaving equals zero

C.All resistors carry equal current

D.Line current equals phase current in every connection

Explanation: KCL states that current into a junction equals current out. It is used with KVL to solve complex LV distribution circuits in examination problems.

9The RMS value of a sinusoidal alternating current is related to its peak value Ip by:

A.Irms = Ip / 2

B.Irms = Ip / √2

C.Irms = √2 × Ip

D.Irms = 0.637 × Ip

Explanation: Irms = Ip/√2 ≈ 0.707 Ip for sinusoidal waveforms. CoP and exam questions use RMS values for cable rating, protection and power calculations.

10The average value of a full-cycle sinusoidal voltage is:

A.Equal to its RMS value

B.Zero

C.0.707 times the peak value

D.Equal to the peak value

Explanation: A symmetrical sine wave averages to zero over a complete cycle because positive and negative halves cancel. RMS and average-over-half-cycle values are non-zero and used differently.

About the HK Grade B Electrical Worker Exam Exam

The Grade B Electrical Worker Registration Examination is the approved technical-knowledge route for candidates who have substantial practical experience but lack recognised academic qualifications for Grade B registration under the Electricity (Registration) Regulations. Grade B work covers LV fixed installations with maximum demand not exceeding 2500 A. The syllabus follows HKEAA Appendix II: general knowledge and circuit theory (including Cap. 406 and the CoP for the Wiring Regulations), cables/enclosures/protection/circuit arrangements, transformers and machines, lighting, and inspection/testing/commissioning.

Assessment

Bilingual (English/Chinese) multiple-choice technical knowledge paper in two parts at a single sitting: Part A 28 questions (pass mark 75%) and Part B 72 questions (pass mark 50%). Candidates must pass both parts together. The exam assesses competence to design, install and maintain low-voltage fixed electrical installations with maximum demand not exceeding 2500 A.

Time Limit

2 hours

Passing Score

Part A ≥75% and Part B ≥50% in the same sitting (both required).

Exam Fee

HK$1,418 per candidate (May 2026 HKEAA online registration). Confirm the live fee on online.hkeaa.edu.hk when you register. (HKEAA (exam delivery) and EMSD (registration of electrical workers after experience assessment))

HK Grade B Electrical Worker Exam Exam Content Outline

22%

General Knowledge and Electrical Engineering Theories

Ordinance/CoP/registration duties, Grade B 2500 A scope, circuit theorems, a.c. quantities, three-phase calculations and power factor.

38%

Cables, Enclosures, Protection and Circuit Arrangement

Cable selection and derating, containment, overcurrent/earth-fault protection, bonding, special locations and discrimination on larger LV boards.

16%

Transformers and Electrical Machines

Transformer operation and paralleling; induction, synchronous and d.c. motors; starting and protection.

Lighting Installations

Lamp types and controllers, installation wiring, stroboscopic effect and exterior/emergency lighting considerations.

16%

Inspection, Testing and Commissioning

CoP test sequence, IR/polarity/Zs/RCD checks, WR1/WR2 certification and equipment commissioning.

How to Pass the HK Grade B Electrical Worker Exam Exam

What You Need to Know

Passing score: Part A ≥75% and Part B ≥50% in the same sitting (both required).
Assessment: Bilingual (English/Chinese) multiple-choice technical knowledge paper in two parts at a single sitting: Part A 28 questions (pass mark 75%) and Part B 72 questions (pass mark 50%). Candidates must pass both parts together. The exam assesses competence to design, install and maintain low-voltage fixed electrical installations with maximum demand not exceeding 2500 A.
Time limit: 2 hours
Exam fee: HK$1,418 per candidate (May 2026 HKEAA online registration). Confirm the live fee on online.hkeaa.edu.hk when you register.

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

HK Grade B Electrical Worker Exam Study Tips from Top Performers

1Memorise the Part A vs Part B pass rules (75% and 50%) and practise under a strict 2-hour limit so you do not spend too long on calculation items.

2Drill CoP bathroom/RCD, insulation-resistance (≥1 MΩ), WR1/WR2 and Grade A/B/C/H scope questions — these are high-yield legislation items that often sit in the harder-marked Part A style.

3Work adiabatic CPC and three-phase/power-factor calculations on paper (as in the official sample: S = √(I²t)/k) and always cross-check cable derating and discrimination on larger LV boards up to 2500 A.

Frequently Asked Questions

What does Grade B electrical work cover in Hong Kong?

Under the Electricity (Registration) Regulations, Grade B electrical work is work on that part of a low-voltage fixed electrical installation whose maximum demand does not exceed 2500 A (single-phase or three-phase). It sits above Grade A (LV ≤400 A) and below Grade C (LV of any capacity), with Grade H covering high-voltage installations.

How is the Grade B registration examination structured and marked?

HKEAA sets a 2-hour bilingual MCQ paper of 100 questions: Part A has 28 questions (pass mark 75%) and Part B has 72 questions (pass mark 50%). You must pass both parts in the same sitting. Passing the exam satisfies the approved-examination qualification route, but EMSD still assesses your practical experience when you apply for registration.

How much does the Grade B exam cost and who runs it?

The May 2026 sitting fee shown on the HKEAA online registration platform is HK$1,418 per candidate. The examination is jointly organised by EMSD, VTC, HKIE and HKEAA; HKEAA handles registration and delivery. There is no entry prerequisite to sit the exam.

What topics does this free practice bank cover?

This bank has 100 multiple-choice questions mapped to HKEAA Appendix II: general knowledge and electrical engineering theories (22%), cables/enclosures/protection/circuits (38%), transformers and machines (16%), lighting (8%), and inspection/testing/commissioning (16%), grounded in the CoP for the Electricity (Wiring) Regulations and Cap. 406.