TRANSMISSION & DISTRIBUTION Centre Appendix 3 Book 1/APPENDIX.pdf · Draw a vector drawing illustrating the relationship between true power, ... A transformer primary has a resistance

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Appendix Training Development Centre

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PRACTICE QUESTIONS

Level III Power Line Apprenticeship

1. An AC 60Hz circuit contains a 6 ohm resistor connected inparallel with a motor which has .0398 Henrys of inductance. Thecurrent through the resistive load is 20A. Draw a vector drawingillustrating the relationship between volts and amps and indicatethe power factor, phase angle and whether it is a leading orlagging power factor.

2. Draw a vector drawing illustrating the relationship between truepower, reactive power and apparent power. Indicate the powerfactor, phase angle and whether it is leading or lagging.

This section is a review for your Power Line Apprenticeshipwritten exams. Complete the questions, and verify your answerswith the Review Question Solutions located at the end of thismodule.

2 T R A I N I N G M A N U A L .

0 2 / 2 4 / 0 5Copyright © 2001 by the Training and Development Centre, SaskPower. All rights reserved.

3. Using the below values, calculate the apparent power and thepower factor:

E = 120VI = 5ATP = 500W

4. Using the below information, calculate the value of Z in an AC60Hz parallel circuit:

E = 220VR = 5.5ΩXL = 4.0ΩXC = 2.0ΩIT = 68A

5. A voltmeter connected to an outlet reads 124V. Calculate themaximum value of the voltage.

6. Explain Kirchhoff’s Law I and II.

P R A C T I C E Q U E S T I O N S A N D S O L U T I O N S 3 .

0 2 / 2 4 / 0 5 Copyright © 2001 by the Training and Development Centre, SaskPower. All rights reserved.

7. Calculate the speed a 12-pole alternator must be driven to produce60 cycles per second.

8. A transformer primary has a resistance of 10 ohms and aninductance of 30 ohms connected across a 100V DC line. Theprimary fuse is rated at 3A. Will the fuse blow? Explain why orwhy not.

9. List two types of losses that occur in a transformer.

10. Indicate the characteristics of the secondary windings of adistribution transformer with regard to voltage and current whenconnected in:

(a) series

(b) parallel



11. List two reasons why oil circuit reclosers are used withcoordinated fuses.

12. List the four main checks to be done on the luminaire when doinggroup bulb replacement.

13. Indicate what an Electrical Permit is.

14. List four hazards to be aware of when opening or closing a cutout.

15. List four factors which affect the sag of a conductor.



16. Indicate four pieces of information which are found on a fulltension splicing sleeve.

17. A 300kg transformer is being lifted by a set of triple sheave ropeblocks in the standing position. Calculate the pull on the fall lineneeded to raise the transformer.

18. The load on a single-phase 240V service is 20hp. Calculate the:

(a) amperage

(b) resistance

(c) cost for 80 hours at 3.5 cents per kWh



19. Calculate the full rated secondary current of a 75kVA 14,400 -120/240V distribution transformer with the secondary windingsparalleled.

20. A 25kVA 14,400 - 120/240V transformer is connected with itssecondary windings in parallel. If the secondary voltage is 119Vand the tap changer is set on 104.5%, calculate the appliedprimary voltage.

21. Calculate the load on a 75kVA 14,400 - 120/240V transformerusing the following information:

Maximeters set on 40:1 scalePhase A = 6.5APhase B = 7.5ASecondary voltage = 122/244



22. List three precautions which must be adhered to when storingprotective rubber equipment.

23. Provincial grid maps are identified by ____________ from southto north and by ____________ from east to west.

24. List three characteristics of the second system of survey.

25. Calculate the power factor of a 3-wire circuit when the combinedwattmeter reading is 2.5kW, the voltmeter reading is 220V, theamperage on Phase A is 6.2A and the amperage on Phase B is18.2A.

26. Explain the purpose of a tap changer in a transformer.



27. Calculate the voltage available to each load in the circuit below.

28. The primary voltage is 24,500V and the turns ratio is 120/1. Themaximeters are on the 20:1 scale. The three ammeters havereadings of:

Y phase = 4.8AB phase = 5.2AR phase = 5A

Using the illustration below, calculate the load in kVA on the bank.



29. The primary line voltage is 25,250V and the transformers arerated at 14,400 - 347V. Build a three-phase bank using a star-starconnection and indicate all line and winding voltages.

30. List four precautions to observe when working with maximeters.

31. The primary voltage is 25kV and the transformer ratios equal25,000/2400V. Supply a 4160V three-phase secondary andindicate all line and winding voltages.



32. The primary voltage is 4200V and the transformer ratio is 2400 - 120/240V. Supply a three-phase 4-wire secondary, using astar-star connection. Indicate all line and winding voltages.

33. The below transformers are rated at 1734 - 60/120V. Connect thetransformers to supply a 120V three-phase 3-wire service andindicate all line and winding voltages.



34. The maximeters are set on 20:1 scale. The transformers in thebelow illustration are rated at 25,000 - 120/240V.

(a) Calculate the load in kVA on the bank.

(b) If the three-phase power factor is 86%, calculate the load inkW.



35. The below transformers are rated at 2595 - 70/140V. Connect thetransformers to supply a 70/140V three-phase 4-wire service andindicate all line and winding volts.

36. The below transformers are rated at 2000 - 100/200V. Using adelta-star connection, supply a three-phase 4-wire service.Indicate all line and winding voltages.



37. List three advantages of a three-phase system over a single-phasesystem.

38. The three windings of a three-phase 60Hz AC generator areconnected in star. Each of the three coil windings is rated at5000VA and 120V. Calculate:

(a) the line voltage

(b) the line current when the generator is delivering its full load

(c) the full load rating of the three-phase generator in kVA

(d) If the power factor of the circuit is 94%, calculate the load inreal or true power.



39. Three coils are connected in delta across a 240V three-phasesupply. The line current is 20A. The total power delivered to thethree coils is 6,000W. Calculate:

(a) the total load in volt amps

(b) the three-phase power factor

(c) the current and voltage in each coil

(d) the impedance in ohms of each coil

40. List three checks which must be made after the installation of anenergy meter and explain how each check is carried out.



41. What is the phase sequence of a three-phase system?

42. What is the Kh factor of a meter?

43. List three reasons for shorting out the secondaries of a CT beforeremoving the meter.

44. List four reasons for using instrument transformers.



45. A single-phase 3-wire 120/240V service has a 15hp loadconnected to it.

(a) What is the drawing number from the meter manual?

(b) What size CT is needed?

(c) If the load is run for 8 hours per day for 50 days, calculate thecost at 3.5 cents per kWh.

46. We have a single-phase 120/240V 3-wire service. The installationconsists of a 100/5 window type CT and a meter with an inherentmeter multiplier of 2. If the reading at the beginning of the monthwas 00002, and at the end of the month it read 00124, calculatethe month bill at 3-3/4 cents per kWh.



47. Which of the three-phase connections can be used as a primaryconnection only?

48. Connect the following transformers to the indicated primary tosupply the required service. Indicate all line and windingvoltages.

Primary line - 25,000V

Secondary required - 208V three-phase

Transformers - 14,400 - 120/240V




Primary line - 4160V

Secondary line - 240V three-phase 4-wire

Transformers - 2400 - 120/240V




Transformer - 2400 - 600V





Secondary required - 600V three-phase 4-wire

Transformers - 4160 - 347V


Primary line - 25,000V

Secondary required - 120/240V single-phase and 240V three-phase

Transformers - 14,400 - 120/240V




Primary line - 25kV


Transformers 14,400 - 2400V

54. A three-phase 240V circuit has 80A on each line. Calculate theamps on the three transformer coils supplying the circuit.



55. A star connected generator is supplying a 14,400V line which isstepped up by a delta-wye transformer to 230,000V.m This is thenstepped down by a wye-wye transformer to 72,000V which isthen stepped down by a delta-wye transformer to 25,000 - whichis then stepped down to 480V by a wye-delta transformer.

(a) Calculate the ratio of each transformer.

(b) Calculate the secondary current, primary current, and linecurrent of each transformer when there is 360A on thesecondary line of the 480V transformer.

(c) Calculate the primary voltage, secondary voltage, andsecondary line voltage of each transformer when thegenerator’s winding voltage is 8,000V.

56. List three characteristics of a series circuit.



57. List three characteristics of a parallel circuit.

58. Resistors of 50, 200 and 250 ohms are connected in series to a100V supply.

(a) Calculate the current through each resistor.

(b) Calculate the voltage drop at each resistor.

(c) Calculate the total resistance of the circuit.



59. Two wires connect a house to a pole. The service is 150 feet longand the resistance of the wire is 2.6 ohms per 1000 feet. If theload is 10 amps and the voltage at the pole is 120 volts, calculate:

(a) the resistance of the circuit

(b) the resistance of the line wires

(c) the voltage drop in the lines (both combined)

(d) the voltage at the house



60. A 4 ohm, 10 ohm and 6 ohm resistors are connected in parallel toa 240V supply. Calculate:

(a) the voltage drop of each resistor

(b) the current through each resistor

(c) the total resistance of the circuit

(d) the total current flow in the circuit

61. Three resistors are connected in parallel to a 120V line. The totalcurrent is 12A. One resistor is 20 ohms and the second is 30ohms. Calculate the resistance of the third resistor.



62. A 122 ohm resistor carrying 1.8A is connected in parallel with a46 ohm resistor. Calculate the current through the 46 ohmresistor.

63. Calculate the cross-sectional area (MCM or KCM) of a wire witha diameter of:

(a) .5 inches

(b) .25 inches

64. A three-phase circuit supplying power to several motors takes 275amperes. If the pressure is 220V and the power factor is 80%,calculate the load in kW.



65. The speed of a generator is 1200 rpm at 60 cycles. Calculate thenumber of poles.

66. A three-phase motor is drawing 12A from a 240V circuit. Thepower factor is 70. Calculate the horsepower output of thismotor.

67. The power in a circuit is 1600W and the current is 12A.Calculate the resistance in ohms.

68. The load on a 2400 - 120/240V three-phase transformer bank is asfollows:

Conductor A - 36AConductor B - 32AConductor C - 28A

Calculate the load on the bank.



69. The load on a single-phase 2400 - 120/240V transformer is asfollows:

A phase - 35AB phase - 43A

Calculate the load in kVA.

70. The primary voltage of a transformer is 600. The secondaryvoltage is 80. If the primary winding has 2400 turns, how manyturns will be on the secondary winding?

71. List three ways in which the strength of an electromagnet may beincreased.

72. List three requirements necessary to induce a current.



73. Explain the purpose of the core in a transformer.

74. A 2400 - 120/240V transformer is energized at 2300V. If 208Aare flowing in the secondary, calculate:

(a) the primary current

(b) the secondary voltage

75. Calculate the applied voltage and current of a 14,400 - 120/240Vtransformer on 104.5% when the secondary voltage is 240V andthe secondary current is 108A.



76. Explain the difference between the a 480 - 120/240V and a 480 - 120V transformer.

77. Calculate the full load current of the following 120/240Vtransformers.

(a) 50kVA

(b) 25kVA

(c) 100kVA

(d) 15kVA



78. The load on a 2400 - 120/240V transformer is as follows:A phase - 5AB phase - 3.8A

The check was done with maximeters on the secondary risers seton 8:1. The voltage was 237V. Calculate the load in kVA on thetransformer.

79. Calculate:

(a) how fast a 12 pole generator must turn to produce a frequencyof 60Hz

(b) how fast it must turn to produce 50Hz

(c) how fast it must turn to produce 60Hz with only two poles

(d) the frequency a 4-pole generator turning at 3600 rpm willproduce



80. Draw and label a sine wave of voltage and current with a 70.7%lagging power factor.

81. A 240V AC 60Hz series circuit contains a 60 ohm resistor and a30 ohm inductive coil. Calculate:

(a) the impedance

(b) the total current

(c) the voltage drop across R and XL

(d) draw a vector diagram of the circuit to illustrate therelationship between volts and amps



(e) the true power

(f) the reactive power

(g) the apparent power

(h) the power factor

(i) the phase angle



(j) draw a sine wave of Eapp and IT

82. Calculate the capacitive reactance using the values below:

(a) frequency = 60Hzcapacitance = 50 microfarads

(b) frequency = 50Hzcapacitance = 53mf

(c) frequency = 60Hzcapacitance = 100f

(d) frequency = 25Hcapacitance = 12f



83. Explain how the phase sequence of a three-phase system can bechanged.

84. Explain the common rule for connecting star and delta.

85. List the voltage and current characteristics of star and delta.

86. Explain what the phase sequence of a three-phase system is.



87. Calculate the phase voltage of the following star lines:

(a) 72kV

(b) 4.16kV

(c) 600V



88. Three coils are connected in delta across a 2400V three-phasesupply. The line current is 18A. The true power is 60,000W.Calculate:

(a) the load in kVA

(b) the E and I of each coil

(c) the impedance of each coil

(d) the power factor



89. The three windings of a three-phase 60Hz AC generator areconnected in star. Each of the three coil windings is rated at500VA and 120V. Calculate:

(a) the line voltage

(b) the line current when the generator is delivering its full load

(c) the full load rating of the three-phase generator in kVA

(d) the load in real or true power if the power factor of the circuitis 94%



90. Three coils are connected in delta across a 240V three-phasesupply. The line current is 20A. The total power delivered to thethree coils is 6000W. Calculate:

(a) the total load in volt amps

(b) the three-phase power factor

(c) the current and voltage in each coil

(d) the impedance in ohms of each coil



91. Connect the two 2400 - 120/240V step down transformers inparallel to provide 240V on the secondary.

92. Parallel the two 4800/2400 - 120/240V step down transformers tothe 4800V line to provide a 3-wire 120/240V secondary.



93. Supply a 4160V three-phase secondary and indicate all line andwinding voltages.

Primary voltage = 25kV

Transformer ratios = 25000/2400

94. Supply a three-phase secondary using a star-star connection andindicate all line and winding voltages (208).

Primary voltage = 4200V

Transformer ratios = 2400 - 120/240



95. The transformers below are rated at 1734 - 60/120V. Connect thetransformers to supply a 120V three-phase 3-wire service.Indicate all line and winding voltages.

96. The transformers below are rated at 2595 - 70/140V. Connect thetransformers to supply a 70/140V three-phase 4-wire service.Indicate all line and winding voltages.



97. A three transformer substation is star delta connected to a 25kVline. If the primary phase current is 20A and the secondary linevoltage is 2400V, calculate the:

(a) voltage across the primary winding

(b) secondary phase current

(c) voltage across the secondary winding

(d) ratio of each transformer

(e) secondary line current



(f) primary line current

(g) kVA load on the bank

98. Calculate the power factor of a circuit in which the voltage is240V, the current is 20A, and the watts are 4000W.

99. Oil circuit reclosers are used with coordinated fuses for twopurposes. Explain each purpose.



100. Using the illustration below, calculate:

(a) the total resistance

(b) the current flow at Point A

(c) the current flow at Point B

(d) the voltage drop across R1, R2, and R3



101. The load on a single-phase 240V service is 20hp. This load is onthe circuit for a period of 8 hours. Calculate the:

(a) amperage

(b) kilowatts

(c) resistance

(d) watts

(e) cost at 7 cents per kWh



102. Calculate the full rated secondary current of a 75kVA transformerwhen the output voltage is 120/240:

(a) with the secondary in parallel

(b) with the secondary in series

103. The load on a 25000 - 2400/4160V substation with themaximeters set on a 40/1 ratio is as follows:

Red = 2Yellow = 2.4Blue = 1.9

Calculate the load on the bank in kVA.

104. A 1400 pound weight is lifted by a set of triple sheave blockswith the pull from the running block. Calculate the pull (in lbs)on the fall necessary to raise the weight (friction 10% per sheave).



105. A customer is located 750 feet from the existing secondary and atemporary 2-wire service of #8 copper is strung in to serve himuntil a line is built. The copper has a resistance of approximately.62 ohms per 1000 feet. If the voltage at the end of the permanentsecondary is 120V and the customer has a 40A load, calculate:

(a) the voltage at the customer’s switch during this load

(b) the power loss in the temporary service

(c) the voltage drop in the temporary service

106. Using the below circuit, calculate the:



(a) total resistance

(b) the current flow at Points A, B, and C

(c) the voltage drop across R1, R2, and R3



107. In the 3-wire circuit below, calculate:

(a) the voltage across the lamp

(b) the voltage across the heater

(c) the total power loss in the conductors



108. The primary voltage is 25,000V. The secondary voltage requiredis 2400/4160V. Using a delta-wye connection, draw in the correctconnections. Indicate all line-line, line-ground, and windingvoltages where applicable. If each transformer has a kVA ratingof 300kVA, calculate the total capacity of this bank to have abalanced load.

109. The primary voltage is 4160V. The secondary voltage required is120/240V three-phase. Using a wye-delta connection, draw in thecorrect connections. Indicate all line-line, line-ground, andwinding voltages where applicable. Show the correct connectionsof the secondary windings. If each transformer has a kVA ratingof 25kVA, calculate the total capacity of this bank for a balancedload.



110. The primary voltage is 25,000V. The secondary voltage requiredis 120/208V. Using a wye-wye connection, draw in the correctconnections. Indicate all line-line, line-ground and windingvoltages where applicable. Show the correct connections of thesecondary windings. Calculate the capacity of this bank for abalanced load.

111. The primary voltage is 25,000V and the transformer nameplatevoltage is 25,000 - 2400V. The secondary voltage required is2400V. What type of connection is required? Using thisconnection, draw in the correct connections. Indicate all line-line,line-ground, and winding voltages where applicable.



112. The primary voltage is 4160V. The secondary voltage required is120/240V three-phase. Using a special open-delta - open-deltaconnection, draw in the correct connections. Indicate all line-line,line-ground, and winding voltages where applicable. Indicate thebastard phase on the secondary. Show the proper connections ofthe secondary windings. If one transformer has a rating of 15kVAand the other has a rating of 10kVA, calculate the total capacity ofthis bank for a balanced load.

113. List four advantages of using a narrow trench when installingunderground cables.



114. List three precautions to observe while trenching.

115. List six points to observe when laying cable in a trench.

116. List two rules regarding backfilling.

117. Explain what duct work is and its purpose.

118. Explain what can be done to spare ducts before backfilling.



119. Explain how fault indicators help in finding a fault location.

120. List the points to consider when drawing underground asbuiltmaps.

121. List the information found on a primary schematic map (singleline drawing of the primary).

122. List the steps to de-energize a cable on a single-phase low profiledead-front load-break transformer.



123. List the steps to de-energize the cables on a three-phase dead-front dead-break transformer.

124. Explain what is done before actual work begins on a primarycable.

125. List the requirements for working in manholes.

126. Explain what is done to cables before they are energized.

127. List the three most common causes of a secondary outage on anunderground system.



128. List the equipment needed to reset a fault indicator on a live-frontsingle-phase transformer.

129. Explain the purpose of an Electrical Permit.

130. List four examples of when an Electrical Permit is required.

131. What is the normal location of an urban meter.



132. What clearance is required for a service:

(a) crossing over private property accessible to pedestrians only

(b) over a driveway (residential)

(c) over a garage

(d) over a SaskTel service

133. Explain the advantage of a four dial register over a five dialregister.



134. Explain what the watt-hour constant is.

135. List four defects which would render a meter unfit for installationon a customer service.

136. List four reasons for using instrument transformers.

137. Explain the main differences between a potential transformer anda distribution transformer.

138. Explain the main differences between a potential transformer anda current transformer.



139. Explain what is meant by the insulation class of a currenttransformer.

140. Explain what is meant by a current transformer rating of 100:5.

141. A current transformer with a rating of 50:5 has 15A flowing in itsprimary winding. Calculate the current flowing in the secondarywinding of the transformer.

142. A window type current transformer has a nameplate rating of200:5A. Calculate the operating ratio if the conductor measuredmakes four turns through the window of the CT.



143. Briefly describe the construction of the following:

(a) 2-wire current transformer

(b) 3-wire current transformer

(c) window or through type current transformer

144. Explain the purpose of a circuit closing device on a currenttransformer.

145. Explain the result of open circuiting the secondary side of a CTwhile the transformer is under load.



146. Explain the differences between a 2-wire self contained socketmeter and a 2-wire transformer type socket meter.

147. When using a current transformer to meter a 3-wire 120/240Vsingle-phase circuit, why is it not necessary to use a 3-wire meter?

148. Explain what is meant by the overall multiplying constant of ametering unit.

149. A metering unit consists of the following equipment:Potential transformer = 600 - 120VCurrent transformer = 50 - 5Meter with an inherent multiplier of 1

If the previous reading was 4628 and the present reading is 4993,calculate the total kWh used.



150. Calculate the overall multiplying constant of the metering unitdescribed in Question 149.

T / F 151. A kWh meter measures the electrical power in a circuit.

T / F 152. The number of kWh recorded for each disk revolution is knownas the watt-hour constant of the meter.

T / F 153. A current transformer is designed for connection in series with acircuit while a potential transformer is designed for connection inparallel with a circuit.

T / F 154. The ratio of a potential transformer is determined in the samemanner as that of a distribution transformer.

T / F 155. A current transformer with an insulation class of 5000V could beused to measure the current on a 600V circuit.

T / F 156. A 2-wire current transformer consists of two primary windingsand two secondary windings.

T / F 157. The circuit closing device in a meter socket is used to short circuitthe potential transformer when the meter is removed.

T / F 158. In a window type current transformer, the conductor measuredbecomes the primary winding.

T / F 159. The standard polarity for an instrument transformer is additive.

160. List three types of equipment used to protect a circuit from toomuch current.



161. Explain how a lightning arrestor protects equipment.

162. Explain the purpose of shield wire.

163. What is the purpose of a fuse and explain how it works.

164. Explain the difference between a cutout and a disconnect.

165. List four safety precautions to observe when operating a cutout.



166. Other than overcurrent protection, explain the purpose of a currenttotalizing breaker.

167. Explain what the two current ratings of a CT breaker mean (eg. 25/41).

168. Calculate the maximum load in kVA which can be put on a10kVA transformer protected by a CT breaker under balanced andunbalanced conditions.

169. Calculate the maximum unbalanced load in kVA which can be puton a 25kVA transformer protected by a CT breaker.

170. Explain what trip free means.



171. Explain the purpose of an OCR in a fuse coordinated circuit andhow it works.

172. Explain the steps to de-energize a single-phase line protected byan OCR.

173. List the steps required to put a regulator into service.

174. List the steps required to remove a regulator from service.

175. The phase-to-phase voltage of a 4-wire delta connection is 240V.Calculate the voltage to ground from the bastard phase.



176. The voltage of a star connected transmission line is 138,000V.Calculate the voltage to ground.

177. Two single-phase transformers connected in open delta areconnected together. Calculate the capacity of the bank.

178. Calculate the load in kVA on a 25,000 - 2400/4160V substation.The maximeter is set on a 8:1 ratio (on the secondary).

Red phase - 6.8ABlue phase - 4.4AYellow phase - 6.2A

179. Calculate the load on a 600/347V wye bank if the current readingis as follows:

Red phase - 42AYellow phase - 35ABlue phase - 21A



180. A three-phase transformer bank is delta-star connected. Eachtransformer is rated 2400 - 120/240V and the primary line currentis 20A. Calculate the:

(a) primary voltage

(b) primary line current

(c) secondary line current

(d) secondary line voltage

(e) secondary phase current



(f) kVA load

(g) ratio of each transformer

181. A three-phase system consists of three separate voltages which are____________ ____________ degrees apart.

182. The closure voltage on a delta bank secondary is ____________.

183. A customer with a lighting load and three-phase load on an open-delta - open-delta bank had his service changed. When the bankwas energized, the motors ran in reverse. Explain the steps youwould take to correct this.

184. A customer has a three-phase 240V load and a 10hp, 5hp and two2hp motors. The bank is served with three 15kVA transformers.Is this a large enough bank to serve him?



185. Draw an open-star - open-delta special connection to providegreater clearance from the transformer tank and grounded parts onthe structure. The primary voltage is 25,000 and the low voltageis 120/240V three-phase.

186. The number of watt hours corresponding to each revolution of thedisc is call the _______________.

187. List three things a meter should be checked for after connection.

188. The CT ratio is 300/5. The meter multiplier is 10. The overallmultiplying constant is _______________.

189. The standard polarity for an instrument transformer is_______________.

190. Explain three reasons why a current transformer should have thesecondary short-circuited during installation or while in a circuitwith the meter removed.


Copyright © 2001 by the Training and Development Centre, SaskPower. All rights reserved. 0 2 / 2 4 / 0 5

191. The nameplate of a current transformer may contain the followinginformation. Explain what each means.

(a) 3-wire

(b) 100/5A

(c) insulation class .6kV

192. Using the below values, calculate:Primary volts - 2400VPrimary turns - 1000Secondary turns - 100Secondary current - 250A

(a) the secondary volts

(b) the primary current



193. If R1 = 12 ohms, R2 = 14 ohms and R3 = 6 ohms, calculate:

(a) the value of RT if connected in parallel

(b) the value of RT if connected in series

194. Using the values below, calculate:E = 120VI = 5ATP = 500W

(a) the apparent power

(b) the power factor



195. Using the information below, calculate:Three-phase powerEL = 208VI = 40APower factor = 80%

(a) the kW

(b) the horse power

196. If R = 5.5 ohms, XL = 4.0 ohms and XC = 2.0 ohms:

(a) calculate the value of Z

(b) illustrate on an impedance triangle



197. The total load on a 2400V - 120/240V three-phase bank is asfollows:

A = 40AB = 45AC = 150A

Calculate the load in kVA.

198. Calculate the speed at which a 12-pole alternator must be drivento produce 60 cycles per second.

199. Define inductance.

200. Define capacitance.



201. If the average voltage is 208V, calculate the maximum voltage.

202. A transformer primary has a resistance of 10 ohms and animpedance of 30 ohms across a 100V direct current line. Theprimary fuse is rated at 3A.

(a) Will the fuse blow?

(b) Explain why.

203. The AC armature is always the:

(a) rotating part of the generator.

(b) stationary part of the generator.

(c) conductor into which voltage is induced.

(d) conductor through which excitor current flows.



204. Explain Kirchhoff’s Law I (current) and Law II (voltage).

205. List two types of losses which occur in a transformer.

206. Explain the purpose of laminating an iron core.

207. Transformers over ____________ kVA and over ____________ Vare manufactured with subtractive polarity.

208. Sketch a diagram illustrating how a polarity check can be madeon a single-phase transformer.



209. The resultant voltage of two coils connected in series is____________ the voltage of one coil.

210. The current in two coils connected in series is ____________ thecurrent in one coil.

211. The resultant voltage of two coils connected in parallel is____________ the voltage in one coil.

212. The current in two coils connected in parallel is ____________the current of one coil.

213. Transposing or twisting lengths of wire:

(a) has no effect on its inductance.

(b) increases the inductance.

(c) doubles the inductance.

(d) decreases the inductance.

214. Explain who is held accountable when an accident occurs on acrew.

215. How often must crew tools and equipment be inspected?



216. List five points which must be covered during a tailboardmeeting.

217. Under what conditions may objects be thrown from the pole tothe ground or from the ground to the pole.

218. Explain what types of injuries must be reported.

219. List nine points to consider before using a ladder.

220. What are the cord requirements for electric hand tools?



221. If a ladder is used to climb a tree, can you then use a chainsaw?

222. List three points to consider when storing rubber equipment.

223. What precaution must be taken when measuring the clearance of aremotely controlled line?

224. List four points regarding the use of hard hats.

225. List two conditions for putting a wire hook on your body belt.



226. What is the minimum gaff length allowed?

227. On what voltages are Class 1 gloves used?

228. What is the minimum distance that the cuffs on Class 1 glovesmust extend past the covers?

229. How often should rubber gloves be inspected and explain how.

230. When is a lineman allowed to climb while wearing rubber gloves?



231. Explain the precaution necessary to reset a fault indicator on aremotely controlled underground primary.

232. What is the best position to be in when working on liveconductors?

233. List four precautions to observe when operating cutouts.

234. What must be done before installing safety grounds on an isolatedcircuit?

235. How many men are required for a job which involves handcontact on primary voltage?



236. How may a lineman extend his reach while working up a pole?

237. How long must an apprentice lineman have worked beforeworking on 240V secondary unsupervised?

238. Explain the difference between Part A and Part B of the StandardProtection Code.

239. What is a Stand-Off Order?

240. List seven reasons why a Stand-Off Order holder would want tocommunicate with the issuing authority.



241. Explain what information must be supplied by the applicantbefore a Stand-Off Order can be issued.

242. Which card or cards are used in conjunction with a Stand-Off?

243. What is a work permit?

244. What condition must the line be in before a work permit may beissued?

245. What information must be supplied before a work permit can beissued?



246. Which card or cards are used in conjunction with a work permit?

247. What instructions must a work permit holder give his crew beforestarting work?

248. When is a circuit said to be properly de-energized?

249. Explain the difference between system grounds and workinggrounds (safety grounds).

250. Shoring or sloping is needed for excavations of ____________and over in depth.



251. Define:

(a) alive

(b) de-energized

(c) grounded

(d) isolated

252. What should be checked for before entering a manhole?



253. List three methods of supporting an unsafe pole.

254. When setting a pole between or near live circuits, whatprecautions are required for the men guiding the pole?

255. List five things a lineman must determine before climbing a pole.

256. List the precautions which should be taken when stringing wireacross streets or highways.

257. What steps should be taken after rupturing a gas line?



258. How close to underground cable is equipment allowed to dig?

259. With regards to grounding, explain what should be done beforeenergizing a transformer.

260. List the steps to be taken before beginning work on undergroundprimary cable.

261. List the three objectives of first aid.

262. List the three steps of effective first aid.



1.

2.

3. (a) apparent power = 600VA(b) power factor = .83 or 83%

4. Z = 3.24Ω

5. Maximum value = 175.3V

6. Law I - the sum of the currents flowing away from a given point in acircuit must equal the sum of the currents flowing to that pointLaw II - the sum of the voltage drops in any one path of an electriccircuit must equal the sum of the voltages applied to that path

7. rpm = 600

8. Yes the fuse will blow. I = 10A while the fuse is 3A

9. copper losscore loss


REVIEW QUESTION SOLUTIONS

Practice Questions and Solutions


10. (a) The resultant voltage of the two windings is double that of onewinding. The current available is the same as that from one winding.

(b) The resultant voltage of the two is the same as that of one winding. The current available is double that of one winding.

11. clear temporary faultsisolate permanent faults

12. level headcheck all connectionscheck for burnt or broken componentsclean the luminaire

13. a form signed by the electrical contractor authorizing SaskPower toprovide a customer with electrical service

14. stand clear of any second point of contactalways use a fusing stick or shotgunprotect face and eyes from possible flashopen and close with firm positive motion

15. size of conductortype of conductorspan lengthtemperature

16. die numbernumber and spacing of crimpssize and type of conductorcatalogue numbertool

17. Tension = 80kg



REVIEW QUESTION SOLUTIONS (CONTINUED)Practice Questions and Solutions

18. (a) I = 62.16A(b) R = 3.86Ω(c) Cost = $41.78

19. I = 625A

20. EP = 14,923V

21. Load = 68.3kVA

22. store in a cool, dark and dry areastore in proper containersstore in natural shape

23. numbersletters

24. road allowances are 99 feet wideroad allowances running north and south are spaced one mile apart, as arethose running east and westsurplus deficiencies are divided among all quarter sections in thetownship

25. p.f. = .93 or 93%

26. to maintain the secondary at a standard or rated voltage

27. E2 = 192VE1 = 202V

28. Load = 35.3kVA


PRACTICE QUESTION SOLUTIONS

Practice Questions and Solutions


29.

30. never change taps while energizedfasten each so they will not short outuse proper tap settingswhen storing meters, set on highest scale

31.

32.


PRACTICE QUESTION SOLUTIONS (CONTINUED)Practice Questions and Solutions


33.

34. (a) Load = 36.5kVA(b) Load = 31.4kW

35.

36.




37. A three-phase generator has a capacity that is about 150% of that of asingle-phase generator with the same size frame.Power generated from a three-phase generator is fairly uniform comparedto that of a single-phase generator.Copper required by a three-phase system is about 70% of that required bya single-phase system.

38. (a) Line E = 208V(b) Line I = 41.67A(c) Load = 14.99kVA or Load = 15kVA(d) Load = 14.1kW

39. (a) Load = 8304VA(b) p.f. = .72 or 72%(c) I = 11.56A

E = 240V(d) Z = 20.76Ω

40. rotation - disc must rotate in direction of the arrow on the face of themeterlight load start - should start to rotate with as little as 15 watts loadmeter creep - shouldn’t rotate more than half a turn after load is removed

41. This is the order in which the induced voltages of a three-phase systemfollow one another.

42. The kh factor of a meter indicates the number of watt hours perrevolution of the disc.

43. Dangerously high voltage buildup could be harmful to the worker.Excessive voltage could puncture isolation on CT windings.Core could become magnetized and alter CT characteristics.

44. A CT is used when wire is too large to fit into meter terminals.A CT is used to reduce amperage down to a level which can be metered.A PT is used to reduce high voltage down to a level which can bemetered (usually 120V).A CT is used to isolate meter installation from high voltage.




45. (a) CD-134(b) 50/50/5(c) Cost = $156.66

46. Cost = $91.50

47. open star

48.

49.

50.




51.

52.

53.

54. Coil I = 46.2A

55. (a) 1:9.223.19:15:130:1




(b) Iline = 7AEline = 2.4AEline = .76AEline = 12A

(c) EL = 221,280VEline = 69,366.8VEL = 24,029VEline = 462V

56. The current is constant.The sum of the voltage drops is equal to the applied voltage.The total resistance of the circuit is equal to the sum of all the resistors.

57. The sum of the branch currents equal the total amount of current.The voltage is constant.The total resistance is smaller than the smallest resistor.

58. (a) I = .2A(b) E1 = 10V

E2 = 40VE3 = 50V

(c) RT = 500Ω

59. (a) RT = 12Ω(b) RL = .78Ω(c) EL = 7.8V(d) EH = 112.2V

60. (a) EVD = 240V(b) I1 = 60A

I2 = 24AI3 = 40A

(c) RT = 1.94Ω(d) IT = 124A




61. R3 = 60Ω

62. I2 = 4.8A

63. (a) 250MCM(b) 625MCM

64. TP = 83.7kW

65. six poles

66. Motor = 4.7hp

67. R = 11.1Ω

68. Load = 23kVA

69. Load = 9.36kVA

70. NS = 320

71. add more wraps of wireincrease the currentmore permeable core

72. conductor in a closed circuitelectromagnetic fieldrelative motion between the two

73. to transfer electrical power by means of electromagnetic induction

74. (a) IP = 20.8A(b) ES = 230V

75. Eapp = 15,048VIP = 1.7A




76. (a) two types of connections resulting in two different voltages(b) only one type of connection resulting in one voltage

77. (a) I = 208.3A(b) I = 104.2A(c) I = 416.7A(d) I = 62.5A

78. Load = 8.34kVA

79. (a) S = 600 rpm(b) S = 500 rpm(c) S = 3600 rpm(d) F = 120Hz

80.

81. (a) Z = 67.1Ω(b) IT = 4A(c) ER = 216V

EXL = 108V(d)




(e) TP = 777.6W(f) RP = 388.8 vars(g) AP = 864VA(h) p.f. = 90%(i) phase angle = 26 degrees lag(j)

82. (a) XC = 53Ω(b) XC = .00008Ω(c) XC = .000027Ω(d) XC = .000221Ω

83. exchange any two connections

84. star - like points are connecteddelta - unlike points are connected

85. delta - Ecoil = Eline

- Iline = Icoil x 1.73- unlike points are connected together

star - Iline = Icoil

- Eline = Ecoil x 1.73- like points are connected together

86. Phase sequence is the way a generator generates or turns three-phasepower. A positive sequence is red, yellow and finally blue.




87. (a) Ephase = 41.618kV(b) Ephase = 2405V(c) Ephase = 347V

88. (a) Load = 75kVA(b) Ecoil = 2400V

Icoil = 10.4A(c) Zcoil = 230.8Ω(d) p.f. = 80.3%

89. (a) Eline = 208V(b) Iline = 41.7A(c) Load = 15kVA(d) TP = 14.1kW

90. (a) Load = 8300VA(b) p.f. = 72.3%(c) Icoil = 11.56A

Ecoil = 240V(d) Z = 20.7Ω

91.




92.

93.

94.




95.

96.

97. (a) Winding E = 14,400V(b) IS = 120A(c) Winding E = 2400V(d) Ratio = 6:1(e) Line I = 207.6A(f) I = 20A(g) Load = 861.95kVA

98. p.f. = 83%

99. clears a temporary fault without causing the fuse to blowisolates a permanent fault from the main line by blowing the fuse




100. (a) RT = 60Ω(b) I = 2A(c) Ed1 = 20V

Ed2 = 60VEd3 = 40V

101. (a) I = 62.16A(b) 14.920kW(c) R = 3.86Ω(d) 14,920W(e) Cost = $8.36

102. (a) I = 625A(b) I = 312.5A

103. Load = 604.5kVA

104. T = 320 lbs.

105. (a) E = 82.8V(b) Power loss = 1488W(c) Ed = 37.2V

106. (a) RT = 11.63Ω(b) IA = 10.315A

IB = 8.44AIC = .94A

(c) R1 = R2 = R3 = RT = 120V

107. (a) Ed of the lamp = 123V(b) E at the heater = 111V(c) WLA = 50W

WLN = 32WWLB = 2W




108.

109.

110.




111.

112.

113. cable location is easiercable can be covered with planksfaster installationless disturbed earth so relandscaping is easier

114. Use proper shoring.Open trenches must be barricaded.Trench for one days work only.

115. Avoid wrapping of power and SaskTel cables.Do not drag cable over ground.Cables should be snaked for settling and frost heaving.Leave additional cable at pedestals and transformers.Cap the ends of all cables (moisture).All cables must be marked.Keep cables away from other utilities (gas, private).




116. Backfill must be free of debris or sand must be used.When backfilling is completed, the area must look the same as when youarrived.

117. Duct is a hollow tube used for connecting manholes, and crossing roadsand private property. They allow for easy installation and removal ofcables.

118. Leave a nylon twine in them and seal the ends.

119. When the fault current passes through the fault indicator, it turns the flagto the red side. Starting at the blown fuse, check the color of theindicators along the line until you come to one which is black. Thisindicates the fault occurred between the the black one and the one beforeit.

120. accurate, clear, concise, up-to-date

121. take-offsdirection of feedtransformer code numbershouse address where the transformer is locatednormal openstype of transformerobvious hazards (N/O at tap-off)

122. Install the feed through and attach the grounds to the transformer ground.Remove the cap from the feed-through.Insert the load break elbow.Put the cap from the feed-through on the bushing insert.Remove the other cap from the feed-through.Insert the test probe.Buzz and ground.




123. Turn the cable oil switch to off.Hang the grounds on the tank and connect to the transformer ground.Test the cables/modiewark.Install cables on the grounds.Put caps on the bushings.

124. Isolate and ground both ends.Spear at the work location.

125. Do not re-rack energized cables.Never close the opening.Do not work alone.Check the atmosphere before entering (gas detector).Have a ladder and rescue rope in position.Use barricades around open manholes.Have a fire extinguisher.Assure proper ventilation.

126. primary - hi-pot to test insulationsecondary - meggar to test insulation and check for cross phasing

127. a dig indamaged pedestalfaulty transformer

128. rubber gloves and a hotstick

129. It gives SaskPower authorization to connect a service.

130. to connect a new permanent serviceto connect a temporary serviceto connect a moved buildingto connect a building which has been vacant for more than one year

131. normally outside 1.5 - 1.7 meters from the final grade, on the side of thehouse closest to the supply




132. (a) 3.5 metres(b) 4 metres(c) 2.5 metres(d) .3 metres

133. Meters are read once a month or every third month. If the load is suchthat it consumes more than 10,000kW in this time frame, it would bedifficult to detect. A five dial meter would reduce this problem.

134. the amount of energy (watt-hours) per revolution of the aluminum disc(represented as kh on the meter)

135. meter creepMeasurements Canada Seal missingdamaged meterinaccurate meter

136. when the load of the service is greater than the meter capacitythe size of the wire makes it impossible to connect to the meter sockethigh voltage insulationreduce high voltage to a meterable level

137. A potential transformer has a very low capacity (rated in volt-amps) andis extremely accurate in its ratio of transformation.

138. Potential transformers reduce the voltage and are always connected inparallel. Current transformers reduce the current and are alwaysconnected in series.

139. the maximum size of voltage the CT can be used on

140. 100A on the service will produce 5A on the metering side of the CT.

141. 1.5A




142. CT ratio = 10:1

143. (a) one primary and secondary winding(b) two primary and one secondary winding(c) no primary winding (the service conductor is the winding), but

has secondary windings. The ratio can be altered by the number of service conductors that pass through it.

144. to short out the secondary windings on the CT

145. the core can become magnetized, thereby altering its characteristicshigh voltage occurring and possibly puncturing the windingsseverely shock anyone coming into contact with it

146. A 2-wire self contained socket meter measures 120V and 100A, whereasa 2-wire transformer type measures 120V and 5A (indicated by a black Xin a yellow box on the meter face).

147. The current transformer replaces the current coils in the 3-wire meter at apredetermined ratio so the 3-wire meter is not needed.

148. It is the multiplication total of the inherent meter multiplier and theinstrument transformers multiplied together and by which the meterreading must be multiplied by for an accurate reading.

149. 18250kW

150. OMC (BM) =50

151. true

152. true

153. true

154. true




155. true

156. false

157. false

158. true

159. false

160. fuses, breakers, OCRs

161. When lightning strikes and the voltage level of the arrestor is reached, itbecomes a low resistance conductor in parallel with the equipment whichit is protecting. Due to its low resistance, it and the equipment receives alow voltage drop and the bulk of the fault current will flow through itinstead of the equipment.

162. Its purpose is to bring ground potential above the lines and structures toprotect them from lightning.

163. Its purpose is to be a weak link which will open the circuit if too muchcurrent flows. When the current flow exceeds the fuse rating, it gets hotand melts.

164. A cutout is a fused device which will open a circuit automatically whenoverloaded. A disconnect is a solid blade which can be operated underno load conditions only.

165. Use a hotstick.Stay clear of ground wires.Shield eyes and face.Use a firm positive motion.

166. Its purpose is to discriminate between the balanced and unbalancedconditions that exist on 3-wire single-phase services.




167. The 25 means that a balanced load of 25A can flow in each hot legbefore the breaker will trip. The 41 means that an unbalanced load of 0Ain one hot leg and 41A in the other can flow before the breaker trips.

168. balanced - 18kVA, unbalanced - 13.2kVA

169. load = 36kVA

170. if the operating handle is held in the closed position, the breaker will stillopen under overload

171. (a) to clear temporary faults and isolate permanent faults(b) When a fault current flows in the circuit, the OCR goes through

two fast operations which allows time for transient faults to be cleared. It then goes through a retarded operation so the fuses canburn and isolate a fault of a permanent nature. If the fault is between the fuses and the OCR, the OCR will go to its fourth operation and lockout.

172. Open the OCR and buzz the line to ensure the OCR has opened.Open the solid disconnect blades and remove the hot tap.Buzz and ground.

173. Set regulator on manual.Set the tap to neutral and confirm neutral.Bypass the regulator.Isolate the line and load.

174. Set the regulator on manual.Set the tap on neutral.Close the line and load.Open the bypass. Set back to automatic.

175. 208V

176. 79,768.8V

177. 86% of two times the smallest transformer




178. Load = 334kVA

179. Load = 33.9kVA

180. (a) EP = 2400V(b) IPline = 20A(c) ISline = 231.2A(d) Eline = 208V(e) 231.2A(f) 83.2kVA(g) 20:1

181. vectorally, 120

182. 0V

183. change any two service cable connections around

184. yes

185.

186. kh factor

187. meter creep, light load starting, correct disc rotation

188. 600

189. subtractive




190. prevents the core from becoming magnetized due to high current, therebyaltering its characteristicshigh voltage occurring and possible puncturing the windingssevere shock to anyone coming into contact with it

191. (a) two primary coils and one secondary coil(b) 100A will produce 5A on the CT at full load (20:1 ratio)(c) can be used on voltages up to 600V

192. ES = 240VIP = 25A

193. (a) RT = 3.11Ω(b) RT = 32Ω

194. (a) AP = 600VA(b) p.f. = 83.3%

195. (a) kW = 11.514(b) HP = 15.43

196. (a) Z = 5.85Ω(b)

197. kVA = 18.684

198. rpm = 600




199. Inductance is the property of an electrical circuit which develops acounter voltage within itself by means of electromagnetic induction.Inductance tends to oppose any changes in current flow in an AC circuit.

200. Capacitance is the property of an electrical circuit that can alternatelystore and release electrical energy by means of an electrostatic field.Capacitance tends to oppose any change in voltage in an AC circuit.

201. Max V = 327

202. (a) yes(b) the load = 10A and the fuse is rated at 3A

203. c

204. Law I - the sum of the currents flowing away from a given point in acircuit must equal the sum of the currents flowing to that pointLaw II - the sum of the voltage drops in any path of an electric circuitmust equal the sum of the voltages applied to that same path

205. copper losscore loss

206. reduce eddy currents, thus reducing heat

207. 500kVA, 34,500V

208.

209. double

210. the same as




211. same as

212. double

213. d

214. The foreman is held accountable for all accidents unless investigationshows the accident was due to conditions beyond his control.

215. at least once a month by the foreman

216. plan or procedure to be followedpotential hazards and ways to eliminate or protect against themindividual work assignmentsuse of special tools or equipmentensure instructions are understood

217. There are no exceptions - tools or equipment may not be thrown up ordown

218. Employees must report all injuries, regardless of severity.

219. Only ladders supplied or approved by the Corporation shall be used.Metal ladders shall not be used on or near live circuits.Linemen shall not wear climbers while on ladders.Ladders shall not be painted.Defective ladders shall be destroyed or cut down.Ladders must be equipped with safety feet or securely held in place.Always face the ladder when climbing.When in a substation, carry the ladder horizontally.The ladder base should not be closer than one quarter of its length andnot further than one third its length from the wall.

220. They must have a three wire cord or be double insulated.

221. Chainsaws shall not be operated from a ladder or in a tree.




222. Rubber should be stored in its natural shape, in the proper container andin a cool dry place.

223. obtain a Stand Off and wear rubber gloves

224. Approved safety helmets shall be worn by all those in the work area.They shall be kept clean.They shall not be used if they are damaged.There should be 32mm (1-1/4 inches) clearance from head.

225. They must be permanently installed and not closer than 150mm (6inches) from the D-ring.

226. 32mm (1-1/4 inches)

227. 300 - 5000V line to line

228. 50mm (2 inches)

229. immediately prior to use by means of an air test and a visual/stretchinspection

230. while climbing into or out of a high voltage areawhile climbing a pole which is supporting live equipment which isknown or suspected of being defective

231. Obtain a Stand-Off.Wear rubber gloves.Use a hotstick.

232. below the wires

233. Use a hotstickShield your face.Avoid the second point of contact.Use a firm positive motion.




234. The circuit must be buzzed with an underground live line tool or checkedfor potential by some other means.

235. There is no minimum providing the lineman is not working alone andone of the people on the ground is wearing climbers and is available incase of emergency.

236. Since you may not fasten both ends of the safety strap to one D-ring, youmust either take the time to let it out or use an extension belt.

237. 2 1/2 years (30 months)

238. Part A applies to remotely controlled circuits and Part B applies to non-remotely controlled circuits.

239. A Stand-Off order is a limited protection which ensures the holder thatauto-reclose features are removed and that making the apparatus alive inthe event of an interruption is forbidden without the consent of the Stand-Off order holder.

240. If he suspects an outage has occurred.If there is an outage, to tell the issuing authority he is clear of the line.If he plans to do any switching on the line.If he wants to temporarily suspend his Stand-Off.Communication checkTo transfer the Stand-Off to another person.To surrender the Stand-Off.

241. name of the supervisor in chargethe apparatus to be coverednature and location of the workdurationradio call signmethod of communication which will be used

242. caution (do not make alive)hold (do not operate)




243. A work permit is a protection guarantee under which specified work is tobe done on specified de-energized apparatus.

244. The line must be de-energized before the work permit may be issued.

245. identity of the applicanta description and location of the apparatusthe protection requiredwork to be donetime and date the work will start and finishname of the intended permit holderif there is to be a power interruption

246. hold (do not operate)grounded

247. apparatus on which work is authorizedneighboring apparatus which is alivesafe guards provided against neighboring apparatus and the precautionsnecessarypoints of isolation and groundingdanger of sectionalizing the apparatus covered

248. when it is grounded at the work location

249. System grounds are usually placed at the point of isolation and are notmandatory. Working grounds are placed at all work locations and aremandatory.

250. 1.5m or 5 feet

251. (a) capable of delivering energy(b) isolated and grounded(c) metallically connected to earth and therefore at earth potential(d) physically disconnected or separated from sources of dynamic

energy




252. dangerous gassesoxygen deficiency

253. rope guysboom trucklashing to a new pole

254. under 5000V - Class 1 rubber glovesover 5000V - rope or insulated sticks

255. voltagedirection of feedbest climbing spaceample protective equipmentpole is in a safe condition

256. Avoid interfering with traffic or pedestrians.Erect warning signs on both sides of the work location.Station flagmen where required.

257. Shut off the engine.Get off, move upwind and do not return.Do not use mobile radio close to the rupture.Post guards to keep people 25m (75 feet) away.Do not smoke in the vicinity.Notify gas staff to shut off the gas.Do not attempt to make your own repairs.

258. The last 1 metre shall be exposed by hand digging.

259. Megger the grid or rod.Ensure all grounds and connections are properly completed.




260. Make sure it is the correct cable.Isolate at both ends.Test for potential and ground at both ends.Spear the cable at the work location.

261. preserve lifeminimize the effects of the injuryrelieve pain and distress

262. diagnosistreatmentdisposal




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TRANSMISSION & DISTRIBUTION Centre Appendix 3 Book 1/APPENDIX.pdf · Draw a vector drawing illustrating the relationship between true power, ... A transformer primary has a resistance