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LINEMAN APPRENTICE 1ST YEAR
EXAM QUESTIONS AND ANSWERS
Based on the safe work model shown in figure 1-2 name 3 elements that have the most direct influence on safe work - Correct Answers - 1.rules & regulations
- Employee training
- Lock out tagging Why is it important to report all accidents or near misses - Correct Answers - In case there is later a report of blood poisoning of a need for knee surgery it is recorded Based on the risk formula if the probability of tipping over while working from a bucket truck is low but the consequence could be very high why is the work considered high risk - Correct Answers - Lineman work is considered high risk because the consequences of accidents are often severe What is the rubber glove rule for your employee - Correct Answers - Ground to ground Cradle to cradle Extended reach Lock to lock What is the purpose for inflating a rubber glove when doing a pre use inspection? - Correct Answers - To inspect for any air leaks What is the difference between a Job briefing and a Job plan - Correct Answers - Job planning includes upstream documentation , written job sequence identification of major hazards Job briefing happens after / before work Name two ways to positively identify a natural wire - Correct Answers - Check if grounded to pole ground Check for neutral connections to transformer How can an isolated line be proven to be de-energized? - Correct Answers - Loto and use pd50 or hot horn What tests are performed before entering a confined space - Correct Answers - Oxygen deficiency, flammable gases and vapors
What are two signs that a coworker may be suffering from heat stress - Correct Answers - Clammy skin, pale and confusion How can a lineman help protect the public from making contact with power lines - Correct Answers - Use barricades, cover dug holes, traffic control, covers over hot meters How can a lineman reduce the risk of a pole falling to the ground while working aloft? - Correct Answers - Support the pole with a line truck Name four safety sources that are a necessity for line work - Correct Answers - CPR, aed, pole top rescue, fire fighting bucket rescue What physical matter is flowing in an electrical current - Correct Answers - The transferring of electrons from one atom to another is electrical current How is high voltage, over 750 V, measured safely - Correct Answers - Measurement of higher voltages is done at substations using voltage transformers (ut) to bring a representative voltage into the control room How can a person get into trouble when measuring voltage with a multimeter - Correct Answers - It is to easy to mistakenly plug the test leads into current jacks when testing voltage Why does a person normally not feel anything when hands are placed on easy post of a car battery - Correct Answers - The potential is only 12v which is not high enough to overcome the resistance of the skin What means can be used to positively identify the Nominal voltage of a primary circuit - Correct Answers - Phase to phase with a pd 50 Do electrons travel at the speed of light in an electrical circuit - Correct Answers - no the speed of electrons in a conductor is about 0.0001 inches. Voltage travels at the speed of light Does electrical current stop once it gets to the load it is feeding - Correct Answers - No electrical current needs a return path Why is opening a ground wire or a neutral on an energized circuit dangerous - Correct Answers - An electrical current could be interrupted when a current is interrupted a voltage will appear across the open point If a circuit is carrying 100 A, what portion of that current could induce ventricular fibrillation and probably death - Correct Answers - 100 milliamperes
What are three common energy sources used to drive a turbine - Correct Answers - Water, wind, steam What is the advantage of a cogeneration power plant - Correct Answers - The electric power can be sold to the grid and the heat, which would otherwise be a waste of heat is sold to a central heating plant Name four alternative electrical energy sources - Correct Answers - Wind energy, geothermal, engines, solar energy, the burning of biomass can be produced as steam. If the voltage on a transmission line could be doubled, how much more energy would it be able to transmit - Correct Answers - The energy that can be transmitted is quadrupled What is the purpose of communications systems between substations - Correct Answers - To transmit information and signals from station to station Name six main segments that make up a distribution systems - Correct Answers - Sub transmission circuits, distribution substation, primary feeders, distribution transformers, secondary systems, customer connections Name three advantages of an overhead distributions system versus an underground system - Correct Answers - Lower cost for conductor and associated switchgear and transformer Easier and quicker detection and repair of a breakdown within the system Much lower cost to upgrade and existing overhead system because of less need to dig up finished streets, curbs, and lawns Name three advantages of an underground distribution system vs an overhead system - Correct Answers - Almost no exposure to storms, trees , automobile , accidents, insulator breakage, and insulator contamination More aesthetically acceptable to public Less public exposure to the possibility of electrical shock. what advantages are there for a three phase versus a single phase circuit - Correct Answers - three interconnected phases provide a smoother power than the relatively more pulsating power of a single phase. what does it mean when the voltages of each phase of a three phase circuit are 120 degrees - Correct Answers - the power generated in each coil reaches its peak and direction at 120 degrees apart wye
what can be done are a three phase transformer bank if a customers three phase motor is running backward - Correct Answers - check rotation to have the three phases in a sequence and change at the transformer or at the service box what determines weather a three phase circuit is considered a wye or a delta circuit - Correct Answers - wye phases are connected together at one point and in parallel to each other delta phases are connected in series what is the voltage to ground on a 4,160 v delta circuit - Correct Answers - 4,160 if one phase of a delta circuit became grounded the voltage between the other two phases and ground becomes equal to the phase to phase voltage why does a source breaker see a phase to ground fault on a delta circuit - Correct Answers - the current flowing back to the source will flow through the transformer and send a signal to the ground fault relay the relay will detect this current and trip out the circuit if the phase to phase voltage on a wye feeder is 25kv, what is the phase to ground voltage - Correct Answers - 25kv / 1.75= 14.4kv what condition would put a very high current on the neutral and also raise the voltage between the neutral and ground - Correct Answers - phase to ground fault the neutral current gets very high and the voltage between the neutral and ground also rise name two advantages for converting a delta circuit to a wye circuit - Correct Answers - fuses and circuit breakers trip out quicker due to over current when there is a good return to path to the source multi grounded neutral on a wye system is an excellent ground and is available for transformers and secondary services a control room operator tells you a 115kv circuit is carrying 70 mva. how much current would a temporary jumper have to carry - Correct Answers - 70,000/198.950= 350 amps 70 kva x 1,000/ 1.73 x e 115kv What are the two types of electrical contact that a Person can make - Correct Answers - In series or in parallel Why does a full-line voltage (recovery voltage) appear across the two ends of a cut conductor - Correct Answers - The resistance across the open point is infinite the voltage (IR) is at full line voltage When making a cut to an isolated and grounded conductor is it necessary to install a jumper across the cut? - Correct Answers - Yes one can accidentally put them self into series with the circuit even an isolated and grounded circuit
why is there voltage across a break in a neutral - Correct Answers - multi grounded neutral all the voltage pushing current appears when cutting or opening when a truck boom is used in the vicinity of an energized circuit, what two ways can a lineman prevent an electric shock should the truck become energized - Correct Answers
- park on ground gradient mat high resistance foot wear truck barricading why is a person not safe when touching a vehicle that is making contact with an energized circuit even though the vehicle is grounded - Correct Answers - parallel path to ground, different potentials what is the purpose for grounding a line truck - Correct Answers - promotes a fast trip out of the circuit if a boom contacts an energized line when a truck boom or crane is used for transmission line work where a circuit is isolated and grounded, should the truck be bonded to the portable line grounds - Correct Answers - yes which electric magnetic fields can cause an immediate health effect - Correct Answers - working close to a microwave tower working in sunlight what two factors are used to make up minimum approach distance tables - Correct Answers - phase to ground exposure distance phase to phase exposure name three other types of underground utilities that can be encountered when digging a new trench for a power cable - Correct Answers - water, gas, communication cable which of the two main types of underground systems require the most civil work to install - Correct Answers - duct and vault systems how does a rope used to a cable get installed into a duct vault - Correct Answers - using a bird line carrier what methods are used to ensure that the maximum cable tension is not exceeded when pulling it into a duct - Correct Answers - checking manufactures cable specifications calculating estimated pulling rates use gauges and monitors name three types of underground Transmisson cables - Correct Answers - HPFF- high pressure fluid filled
HPGF- high pressure gas filled GIL- gas insulated line how does the backfill for an underground cable affect the current-carrying capacity of the cable - Correct Answers - by effecting heat dissipation name three methods used to protect direct buried cable - Correct Answers - sand big pipe pvc pipe name three advantages of a vault and duct system for an underground system over a direct bury system - Correct Answers - easy access section of cable can be installed or replaced no excavation true or false in a joint use trench, power cables are laid in the top position - Correct Answers - false identify cables in this joint use trench - Correct Answers - electric, gas, oil, steam, communications, water, sewer, arrogation, proposed excavation, temporary source tape .
