Electrical Application Serviceperson (Qualified ...€¦ · You have 10 minutes to read this paper but do not start writing until instructed to do so by the supervisor

EASQ 3014

Candidate Code No.

For Board Use Only

Result Date Int

Result Date Int

ELECTRICAL APPLIANCE SERVICEPERSON (QUALIFIED) EXAMINATION

18 June 2016 QUESTION AND ANSWER BOOKLET

Time Allowed: 2 Hours INSTRUCTIONS – READ CAREFULLY

You have 10 minutes to read this paper but do not start writing until instructed to do so by the supervisor.

Write your Candidate Code Number in the box provided above. Your name must NOT appear anywhere in this paper.

Answer all questions.

The pass mark for this examination is 60 marks.

Use a pen for written answers. Do not use a pencil or a red pen.

Drawing instruments and pencils may be used when diagrams are required. Marks are allocated on the basis of correctness.

Do not use correcting fluid or correcting tape.

It is recommended that the reference source for your answers be included in the space provided if a question can be answered from the Act, Regulations, Standard or Code. However, just stating a reference only will earn no marks.

For calculation questions all workings, including formulae, must be shown to gain full marks.

You will need to use the following documents in this examination:

● Electricity (Safety) Regulations 2010 reprint dated 1 August 2014 or the Electricity (Safety) Regulations 2010 reprint dated 4 April 2016.

● AS/NZS 3760:2010

PLEASE HAND THIS PAPER TO THE SUPERVISOR BEFORE LEAVING THE ROOM

(turn over)

EASQ 3014 QUESTIONS – 18 JUNE 2016

2

Question 1 Each part in this question is worth 2 marks. Write the identifying number, 1 or 2 or 3 or 4, for each part in the box provided (a) A 230V heater comprises two elements connected in parallel across the

supply. If one element becomes open-circuited, what is the voltage across the other element?

1. 115 V 2. 460 V

3. 230 V 4. 0 V (b) A 240V/230V electric hair dryer is rated at 920 watts when operating at

240 volts? What current will be drawn when the hair dryer is operating at 230V? 1. 3.67 A 2. 2.5A

3. 0.25 A 4. 4.17 A (c) State the reason why a bayonet cap adaptor must not be used to supply a

230V, Class I, 2 kW electrical appliance. 1. Wrong voltage rating 2. The current rating is too low 3. It has the wrong colour coding 4. The cord supplying the adaptor is the wrong shape

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3

Question 1 continued (d) An insulation resistance test of a 230V, Class I, food mixer has been carried

out. Which of the following test results will permit the appliance to be returned to service?

1. 1.25 Ω 2. 1 Ω

3. 0.5 MΩ 4. 3 MΩ (e) An HRC fuse has a minimum fusing current of 12.5 amps and a Utilisation

category (fusing factor) of 1.25. The current rating of this fuse is: 1. 25 A 2. 16 A 3. 15 A 4. 10 A (f) Under which of the following circuit conditions is the electro-magnetic

mechanism of an MCB specifically designed to operate (trip)? 1. An earth leakage 2. An overload of short duration

3. A short circuit 4. A high motor starting current

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4

Question 1 continued (g) If the resistance in a circuit is doubled and the current flowing is halved,

the applied voltage will be: 1. The same 2. Doubled

3. Four times greater 4. Halved (h) Which of the following switches would be used in a single-phase, split-

phase motor to open the start winding? 1. A three heat switch 2. A centrifugal switch

3. A thermostat 4. A simmerstat (i) A 230V Class I electrical appliance with a phase to framework fault is being

used outdoors. Which of the following protection devices will prevent the operator receiving

a severe electric shock? 1. A RCD 2. An HRC fuse

3. An overload relay 4. A rewireable fuse

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5

Question 1 continued (j) Which type of switch has a bi-metal strip that heats up and controls load by

switching on and off on a time basis. 1. A three heat switch 2. A thermostat

3. A simmerstat 4. A centrifugal switch

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6

Question 2 Test instruments are used to test three live circuits. (a) The readings for Circuit 1 are:

Supply Voltage

Resistance Current Watts

6.53

1502

(i) Calculate the resistance of Circuit 1.

(2 marks) (ii) Calculate the supply voltage of Circuit 1.

(2 marks)

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7

Question 2 continued (b) The readings for Circuit 2 are:

Supply Voltage


51.3

236

(i) Calculate the supply voltage for Circuit 2.

(2 marks) (ii) Calculate the current drawn by Circuit 2.

(2 marks)

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8

Question 2 continued (c) The readings for Circuit 3 are:

Supply Voltage


30.65

7

Calculate the power dissipated by Circuit 3.

(2 marks)

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9

Question 3 (a) (i) Draw and label a circuit diagram showing of a 230V, 1500 W, Class

II, single phase electric heater that shows: ● The polarity of the supply. ● A fuse protecting the circuit. ● A switch controlling the circuit. ● The element.

(3½ marks) (ii) Calculate the maximum current the flexible cord supplying the heater

is required to carry. (2 marks)

(iii) State the minimum size HRC fuse that is requited to protect the

heater. (½ mark)

________________________________________________________

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10


11

Question 3 continued (b) The element in the heater in (a) has become faulty. The element has been replaced by two 1000 W elements connected in

parallel.

(i) Calculate the maximum current the flexible cord supplying the heater is required to carry with the two new elements installed.

(2 marks) (ii) Will the HRC fuse in the heater need to be changed because of the

new elements installed? State a reason to support your answer. (1½ marks)

________________________________________________________

(c) Will the power dissipated by the heater decrease or increase if the supply voltage was 240V

(½ mark) ____________________________________________________________

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12

Question 4 (a) (i) When replacing a blown HRC fuse cartridge, the replacement must

have characteristics the same as the original. One of these characteristics is the voltage rating.

State THREE other electrical characteristics to be checked for

similarity. (3 marks)

(1) ____________________________________________________

(2) ____________________________________________________

(3) ____________________________________________________ (ii) Define the term voltage rating as it applies to an HRC fuse.

(1 mark) ________________________________________________________ ________________________________________________________ ________________________________________________________ (b) State TWO advantages that HRC fuses have when compared to rewireable

fuses. (3 marks)

(1) ________________________________________________________

________________________________________________________

________________________________________________________ (2) ________________________________________________________

________________________________________________________

________________________________________________________

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13


14

Question 4 continued (c) A rewireable fuse is being reloaded. State TWO reasons why it is important to thread the fuse wire from

terminal to terminal through the tortuous path in the fuse carrier. (2 marks)

(1) ________________________________________________________

________________________________________________________

_______________________________________________________

(2) ________________________________________________________

________________________________________________________

________________________________________________________

(d) A 16A HRC fuse cartridge protecting a final subcircuit has blown. The cartridge has been replaced with a 32A fuse cartridge.

State what would happen if the number of electrical appliances being used

overloaded the final subcircuit. (2 marks)

____________________________________________________________

____________________________________________________________

____________________________________________________________

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15

Question 5 (a) The main switch on a switchboard is to be turned off so blown HRC fuse can

be placed. The fuse protects a socket outlet final subcircuit supplying a single-phase plug-in electrical appliance.

What important check should be made before turning off the main switch?

(1 mark)

____________________________________________________________

____________________________________________________________

(b) For a faulty permanently-connected electrical appliance: (i) What does switching off the appliance mean?

(1 mark)

________________________________________________________

________________________________________________________

(ii) What does isolating the appliance mean? (2 marks)

________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ (c) A 230V permanently-connected electrical appliance has been isolated and

tagged. Describe TWO methods of ensuring that the electrical appliance remains

isolated while left unattended (2 marks)

(1) ________________________________________________________ ________________________________________________________ (2) ________________________________________________________ ________________________________________________________

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16

Question 5 continued (d) Two multi-function test instruments are being used to measure voltage and

current values of a live 230V electrical appliance. State TWO precautions relating to the test instruments that will ensure

personal safety. Note: 1. All the necessary safety equipment (overalls, rubber mats

etc.) is available. 2. Set procedures are available. 3. All conductive items (e.g., rings) have been removed.

(2 marks) (1) ________________________________________________________

________________________________________________________

________________________________________________________

(2) ________________________________________________________

________________________________________________________

________________________________________________________

(e) Refer to the Electricity (Supply) Regulations 2010 and state ONE practical

step an employee must take when carrying out work requiring the use of personal protective equipment.

(2 marks) ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________

Ref: …………………………………………

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17

Question 6 (a) (i) Refer to the Electricity (Safety) Regulations 2010 and define the term

standard low voltage as it applies to single-phase plug-in electrical appliances.

(1 mark) ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________

Ref: ………………………………………… (ii) Refer the Electricity (Safety) Regulations 2010 and define the term

low voltage. (1 mark)

________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________

Ref: ………………………………………… (iii) Refer the Electricity (Safety) Regulations 2010 and define the term

insulated. (1 mark)

________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________

Ref: …………………………………………

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18

Question 6 continued (b) A 230V electrical appliance is not constructed so as to be safe under both

normal and abnormal conditions. Refer to the Electricity (Safety) Regulations 2010 and state the reason why

this electrical appliance cannot be put into service. (2 marks)

____________________________________________________________ ____________________________________________________________ ____________________________________________________________

Ref: ………………………………………… (c) For the New Zealand low voltage MEN system state: (i) The nominal voltage between the neutral conductor and earth

(½ mark) ________________________________________________________ (ii) The nominal voltage between any active conductor and the neutral

conductor (½ mark)

________________________________________________________ (iii) The nominal voltage between any active conductor and earth

(½ mark) ________________________________________________________ (iv) The nominal voltage between any two active conductors

(½ mark) ________________________________________________________

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19

Question 6 continued (d) The New Zealand single phase 230V a.c. supply operates at a frequency of

50 Hz. Define the term Hz. (1 mark)

____________________________________________________________

____________________________________________________________

____________________________________________________________ (e) An operator uses a Class I, 230V electrical appliance in damp conditions

without an electrical safeguard. Describe the danger that may exist for the operator if a phase to frame

fault occurs in the appliance. (2 marks)

____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________

(turn over)


20

Question 7 (a) The following is a circuit diagram of a 230V single-phase induction motor. (i) Name the parts of the diagram

(3 marks) A. ____________________________________________________ B. ____________________________________________________ C. ____________________________________________________ D. ____________________________________________________ E. ____________________________________________________ F. ____________________________________________________

(ii) From the diagram, name the part or parts you would alter to change

the direction of rotation of the motor. (1 mark)

________________________________________________________ ________________________________________________________

(turn over)

A

B

C

D

E

F


21

Question 7 continued (iii) What would occur if part B in the diagram was open-circuited and the

motor was switched on? (1 mark)

________________________________________________________ ________________________________________________________ (iv) What would occur if part D in the diagram was open-circuited while

the motor was running on load? (1 mark)

________________________________________________________ ________________________________________________________ ________________________________________________________ (b) Describe how the direction of rotation can be reversed for a universal

motor. (1 mark)

____________________________________________________________ ____________________________________________________________ (c) Calculate the current drawn by a motor if the nameplate information reads: Voltage 230 Phases 1 Horsepower 0.75 Speed 1425 r.p.m.

(3 marks)

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22


23

Question 8 (a) Instrument tests are being carried out on a 230V, Class I, plug-in electrical

appliance. (i) State ONE reason why an earth continuity test is carried out.

(1 mark) ________________________________________________________

________________________________________________________

________________________________________________________ ________________________________________________________ (ii) State ONE reason why a polarity test is carried out.

(1 mark) ________________________________________________________

________________________________________________________

________________________________________________________ ________________________________________________________ (iii) State ONE reason why an insulation resistance test is carried out.

(1 mark) ________________________________________________________

________________________________________________________

________________________________________________________ ________________________________________________________

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24

Question 8 continued (b) Explain why it is important to carry out an earth continuity test on a Class I

electrical appliance before carrying out an insulation resistance test (2 marks)

____________________________________________________________

____________________________________________________________

____________________________________________________________

____________________________________________________________ (c) A polarity test is carried out on a Class I electrical appliance after it has

been repaired and the flexible cord replaced. The appliance is controlled by a single-pole switch.

Detail the THREE important points this polarity test will confirm?

(4 marks) (1) ________________________________________________________

________________________________________________________

(2) ________________________________________________________

________________________________________________________

(3) ________________________________________________________

________________________________________________________

(d) (i) What type of test instrument would you use to test for polarity? (½ mark)

________________________________________________________ (ii) What range would you select on the test instrument?

(½ mark) ________________________________________________________

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25

Question 9 (a) An earth continuity test is required to be carried out test on a 230V, Class I

fixed-wired electrical appliance before it is reconnected to a permanent-connection unit.

(i) State the instrument used for this test.

(1 mark) ________________________________________________________

________________________________________________________ (ii) Describe how this test is carried out.

(2 marks) ________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________ (iii) State an acceptable resistance for this test that would permit the

appliance to be reconnected and returned to service. (1 mark)

________________________________________________________ (b) State ONE reason why an ohmmeter is not the correct instrument to carry

out an insulation resistance test on a portable electrical appliance. (1 mark)

____________________________________________________________

____________________________________________________________

____________________________________________________________

____________________________________________________________

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26

Question 9 continued (c) A replacement flexible cord is to be fitted to a 230V, Class I, plug-in

electrical appliance: (i) State the minimum number of cores required for the flexible cord.

(½ mark) ________________________________________________________ (ii) Refer to AS/NZS 3760 and state ONE set of colours and polarity for

the conductors of the flexible cord. (3 marks)

________________________________________________________ ________________________________________________________ ________________________________________________________

Ref: ………………………………………… (iii) State the actions detailed in AS/NZS 3760 that are required to be

carried out before the Class I electrical appliance can be returned to service.

(1½ marks) ________________________________________________________ ________________________________________________________ ________________________________________________________

Ref: …………………………………………


27

For Candidate’s Use For Examiner’s Use Only Questions

Answered Marks

In the box, write the number of EXTRA sheets you have used. Write NIL if you have not used any

1

2

3

4

5

6

7

8

9

TOTAL

Documents

Electrical Application Serviceperson (Qualified ...€¦ · You have 10 minutes to read this paper but do not start writing until instructed to do so by the supervisor