NATIONAL CERTIFICATE (VOCATIONAL) ELECTRICAL WORKMANSHIP NQF LEVEL 4 NOVEMBER 2009

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1 NATIONAL CERTIFICATE (VOCATIONAL) ELECTRICAL WORKMANSHIP NQF LEVEL 4 NOVEMBER 2009 ( ) 25 November (X-Paper) 09:00 12:00 A non-programmable scientific calculator may be used. This question paper consists of 7 pages.

2 ( ) -2- NC750(E)(N25)V TIME: 3 HOURS MARKS: 100 NOTE: If you answer more than the required number of questions, only the required number of questions will be marked. All work you do not want to be marked, must be clearly crossed out. INSTRUCTIONS AND INFORMATION Answer ALL the questions in SECTION A. Answer any ONE question in SECTION B. Read ALL the questions carefully. Number the answers according to the numbering system used in this question paper. Use π = Write neatly and legibly.

3 ( ) -3- NC750(E)(N25)V SECTION A QUESTION 1: TYPICAL ELECTRICAL INSTALLATIONS 1.1 Refer to FIGURE 1 below and identify components A to D. Do NOT redraw the sketch. Write only the letter (A D) and the answer next to it in the ANSWER BOOK. 1.2 Draw the IEC symbol for the following: FIGURE 1 (4) Wires joined (1) A motor (1) Transformer (1) 1.3 A series circuit consists of a 25 ohm resistor, an inductor of 35 mh and a capacitor of 75 µf. This circuit is connected to a 220 V, 60 Hz supply. Calculate the following: Inductive reactance (2) Capacitance reactance (2) The impedance (3) Total current in the circuit (2) 1.4 Define potential difference (pd). (2) 1.5 Regulation in SABS 0142 (SANS ) focuses on equipment earthing. Briefly describe this regulation. (2)

4 ( ) -4- NC750(E)(N25)V QUESTION 2: DOMESTIC APPLIANCES 2.1 Define the term fixed appliance as per SABS 0142 (SANS ). (2) 2.2 A customer complains that the water in the geyser is not getting hot. After close inspection and testing you discover that the heating element is faulty. You are required to replace the heating element. Write ALL steps you would follow for the replacement of the heating element. (5 x 1) (5) 2.3 What does the SANS regulation stipulate with regard to the installation of water heaters, including geysers? (3) 2.4 TABLE 1 below shows the problems of a steam iron that were reported by the customer. Complete the table by providing the possible causes and remedies/corrective actions. Write only the answer next to the question number ( ) in the ANSWER BOOK. TABLE 1 PROBLEM POSSIBLE CAUSES REMEDIES/CORRECTIVE ACTIONS The steam iron does not work at all The steam iron overheats (6) 2.5 Earth continuity conductors form part of an installation and are compulsory for electrical installations as per SABS 0142 (SANS ) regulation List FOUR requirements of SABS 0142 (SANS ) for earth continuity conductors. (4) QUESTION 3: LOW VOLTAGE TRANSFORMER AND SWITCHGEAR 3.1 Design a work area checklist that can be used to assess the floors and storage space in your work area. (6) 3.2 State FIVE general operating procedures of a company. (5) 3.3 Transformer oil erodes from time to time. You, as the technician, need to do sampling. Indicate the basic equipment needed to perform this task. (2 x1) (2) 3.4 Name TWO types of main mechanisms that can be found in industrial switchgear. (2) 3.5 Regulation (SANS ) states that every distribution board must be controlled by a switch disconnector. Explain these regulations. (5 x 1) (5)

5 ( ) -5- NC750(E)(N25)V QUESTION 4: ELECTRICAL MACHINES AND CONTROL GEAR 4.1 Name THREE types of single-phase induction motors. (3) 4.2 Make a simple sketch that explains the operation of an auto-transformer. (5) 4.3 According to the Electrical Machinery Regulations, 1988, there are certain regulations that govern electrical control gear. State these regulations. (6 x 1) (6) 4.4 Indicate whether the following statements are TRUE or FALSE. Choose the answer and write only 'true' or 'false' next to the question number ( ) in the ANSWER BOOK Lockout is the use of a lock to make machinery or equipment inoperable, or to isolate an energy source. (1) Lockout is important for machine operators, maintenance crews and any personnel required to work near moving parts. (1) The purpose of lockout is to prevent the release of an energy source that could activate moving parts on equipment. (1) 4.5 Describe, with the aid of a sketch, how direct-on-line control gear is connected. (3) TOTAL SECTION A: 80

6 ( ) -6- NC750(E)(N25)V SECTION B Answer ONE question in this section. QUESTION 5: SAFETY AND FIRST AID 5.1 There are accidents that are caused by bad housekeeping. Indicate FOUR good housekeeping rules that can prevent these frequently occurring accidents from happening in the workplace. (4) 5.2 Complete TABLE 2 below by writing only the answer next to the question number ( ) in the ANSWER BOOK. TABLE 2 DEGREE OF THE SYMPTOMS TREATMENT BURN First Superficial 2 nd Cool water. Do not break blister Open wound, wet, white, temporary scarring Third Cool running water, wet bandages or burn shield, then transport to doctor (6) 5.3 State FIVE objectives of the Mine Health and Safety Act, 1996 (Act 29 of 1996). (5) 5.4 The safety officer needs to ensure that incidents are reported according to the Occupational Health and Safety Act, 1993 (Act 85 of 1993). Indicate how incidents should be treated and reported. (5) OR QUESTION 6: ELECTRICAL ENTREPRENEURSHIP 6.1 All business transactions have records that have to be kept for financial reasons. Name FOUR sources of transactional documents. (4) 6.2 A client consults with you regarding the setting up of an electrical business. As the consultant you need to conduct a feasibility study on the aspects of the business such as profits, sales, fixed costs, variable cost and operating costs. Discuss, using brief notes to your client, the above-mentioned aspects of an electrical business. (5 x 2) (10)

7 ( ) -7- NC750(E)(N25)V 6.3 There is a difference between an entrepreneur and intrapreneur. Tabulate THREE of these differences. (3 + 3) (6) TOTAL SECTION B: 20 GRAND TOTAL: 100

NATIONAL CERTIFICATE (VOCATIONAL) ELECTRICAL SYSTEMS AND CONSTRUCTION NQF LEVEL 3 NOVEMBER 2009

NATIONAL CERTIFICATE (VOCATIONAL) ELECTRICAL SYSTEMS AND CONSTRUCTION NQF LEVEL 3 NOVEMBER 2009 (12041033) 24 November (X-Paper) 09:00 12:00 This question paper consists of 6 pages. (12041033) -2- NC720(E)(N24)V