MULTIPLE CHOICE:

MULTIPLE CHOICE:

INSTRUCTION: Each item in this section has FOUR (4) suggested answers letters (A), (B), (C), (D). Read each item carefully before ticking () the best choice.

1. Which of the following is the factor that determines a good bend?

(A) The radius of it

(B) The uniformity of the conduit throughout

(C) The smoothness of the finished job

(D) The type of machine used to produce it

2. An electrical conduit is to be installed on the surface of a wall; however it is to cross an already installed conduit. Which of the following is the best way of overcoming this obstacle?

(A) Creating a saddle bend

(B) Creating an offset bend

(C) Cutting through the installed conduit to make way for the one to be installed

(D) Using spacer bars

3. All of the following are devices used in changing the direction of a conduit run EXCEPT.

(A) Bending Block

(B) Spring Bender

(C) Bending Machine

(D) Bending Mould

4. Which of following is the main advantage of using electrical conduit?

(A) Ease of erection

(B) Current capacity

(C) Mechanical protection

(D) Neatness of finish

5. After completing an electrical installation the following tests should be carried out EXCEPT.

(A) Earth continuity

(B) Continuity

(C) Open circuit

(D) Verification of polarity

6. A Phillips screw driver can be identified by the

A.flat point

B.star looking points

C.long nose

D.square point7The improper selection of hand tools for a particular job can result in damages to

A.person and equipment

B.tools and tool kit

C.the supply authority equipment

D.the electrical installation and equipment

8.An open-ended wrench that has one moveable jaw is called a/an

A.tubing wrench

B.adjustable wrench

C.ratcheting wrench

D. convenient wrench

9.Which is the BEST definition of an insulator?

A. An insulator is oil resistant, heat resistant and flame retardant

B. Includes all devices, fittings, accessories and appliances in which conductors are used

C. All non-metallic substances such as rubber and glass maintained at 00C

D. Any substance that when put against a live conductor does not allow the holder to get shock

10.The entry of cable end into an

accessory is known as

A. termination

B. connection

C. jointing

D. soldering

SHORT ANSWER

INSTRUCTION: Read each question in this section and place their correct responses in the corresponding space provided.

1. What is the effect of NOT connecting ALL live wires through switches?

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2. How should handy boxes, octagonal boxes and other metal components, not designed to carry current in an installation, addressed according to the regulation?

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3. For a domestic dwelling, what is the standard height in which switches are placed?

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4. What is the recommended type of outlet that should be used in bathrooms and kitchens?

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5. A resistor which is coded Red, Orange, Red-Silver was measured to be 3 000 ( should this resistor be replaced? Why?

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6.Which instrument is used to measure voltage?

7.Which instrument is used to measure current?

8.When measuring the current going into load how the meter is connected?

9.Which of the following; voltage, current and resistance; is measured when the circuit is de-energised?10.The flow of charged particles in one direction is called?

11.The opposition to the flow of electric current is called?

12.What is the symbol for electric current?

13. The unit for electrical resistance is the?

14.What type of current does a battery supplies?

15.In which type of circuit is the voltage constant?

16.In which type of circuit is the current constant?

17.What is a close path for current flow called?

18.A circuit condition in which there is direct connection between the live and neutral is called?

19.Which meter is used to test for an open circuit?

20.Which of the following, the Ohm-meter, voltmeter, and the Ammeter, is used to test for continuity?

LISTING

INSTRUCTION: Read each question in this section and place their correct responses in the corresponding space provided.

1. State TWO advantages of PVC conduit over metallic conduit

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2. List THREE (3) accessories that are used in the termination of conduits.

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3. Name TWO (2) devices that are used for cutting conduits.

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4. State TWO advantages of connecting lamps in parallel

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5. List THREE (3) regulations relating conductors and cables used in electrical installation.

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6.Identify the TWO (2) types of current.

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CASE STUDY

INSTRUCTION: Read the following case then answer correctly the questions that follows in the space provided.

William, an electrician employed to Nedricks Electrical, was given the task of completing an installation for a TWO (2) bedroom board house. On completion, he was recalled by the customer due to discomfort expressed of having the light switch placed behind a door. The customer also complained of lights not lighting at times and going out periodically.

When his supervisor came to rectify the concerns he further found lights and outlets were protected by the same circuit breaker.

1. What regulations did William not conform to?

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2. What are the possible reasons that would lead to the lights slow, periodical or non-response?

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3. What test should be carried out when finding the fault in this circuit?

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APPLICATION1. For the householder below calculate the cost for the total energy usage for a 1 month period at a rate of $9.50 per kwh.

(12 marks)

Table 1: The number of Watts used by each appliance per hour

Name of Appliance No. of Watts Name of Appliance No. of Watts

Clock

10 Refrigerator/Freezer 326

Range/Oven

12,200 Television

200

Washing Machine

512 Iron

1100 Toaster

1620 Microwave Oven

1500 Vacuum Cleaner 1500

Fan

100

Householder A

Name of Appliance Hours used No. of Kilowatt Hours used

Refrigerator/Freezer 720

Television 130

Washing Machine 140

Iron

240

Vacuum Cleaner 20

Coffee Maker 120

Range/Oven

30

Microwave Oven 240

Fan

400

Total No. of Kilowatt hours for the month =

2. A 400KVA, 50Hz single phase transformer has a turns ratio of 60:1, if the unit is connected to a 24kv supply, determine the full load secondary current at unity power factor.

(4 marks)

3. Find the length in cm of the aluminium wire needed to obtain a resistance of 16 ohms for this wire P = 0.00013 ohm-cm and A = 0.013cm (Round to the nearest centimetre)

(3 marks)

4. A d.c. motor with a terminal voltage of 500 V has an armature resistance of 0.2 . Calculate (a) the value of the back e.m.f. when the armature current is 50 A, and (b) the value of the armature current when the back e.m.f. is 495 V. Ignore field current and brush drop.

(4 marks)

5.

(a) Calculate (i) RT (2 marks)

(ii) IT (2 marks)

(iii) IR2 (2 marks)