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IEC 4TH YEAR FINAL EXAM AND PRACTICE
EXAM 2024 | ALL QUESTIONS AND
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IEC 4TH YEAR FINAL EXAM
When emergency system power generators are out of service for major maintenance or repair, ___ shall be available. Select one: a. utility power b. a temporary or portable alternate source c. a wind powered source d. a solar powered source e. any of these ------CORRECT ANSWER---------------b. a temporary or portable alternate source A typical standby system ATS ___. Select one: a. transfers the electrical load to the generator when the normal source fails b. disconnects the normal power source connections when the normal power source fails c. signals the generator to stop when the normal power source is restored d. transfers the load back to the normal power source when the normal source is restored e. all of these ------CORRECT ANSWER---------------e. all of these
Transfer equipment for emergency systems shall be designed and installed to prevent the inadvertent interconnection of ___ sources of supply in any operation of the transfer equipment. Select one: a. normal and emergency b. grounded and ungrounded c. utility and permanent d. temporary and generator set ------CORRECT ANSWER---------------a. normal and emergency Audible and visual signal devices on emergency system transfer equipment shall be provided where practicable for ___. Select one: a. indicating that the battery is carrying the load b. indicating derangement of the emergency source c. indicating that the battery charger is not functioning d. indicating a ground fault in a solidly grounded wye emergency system of more than 150 volts to ground and circuit protective devices rated 1, amperes or more e. all of these ------CORRECT ANSWER---------------e. all of these Storage batteries, other than lead-acid batteries, shall be ___. Select one: a. exposed b. approved c. identified d. listed ------CORRECT ANSWER---------------d. listed For battery chemistries with ___ electrolyte, the structure that supports the battery shall be resistant to deteriorating action by the electrolyte. Select one: a. gaseous b. solid c. liquid
d. 6 ------CORRECT ANSWER---------------b. 12 Photovoltaic systems with PV system dc circuits operating at ___ volts dc or greater between any two conductors shall be protected by a listed PV arc-fault circuit interrupter or other system components listed to provide equivalent protection. Select one: a. 80 b. 30 c. 300 d. 150 ------CORRECT ANSWER---------------a. 80 A rapid shutdown switch for PV systems shall have a label located on or no more than ___ feet from the switch. Select one: a. 3 b. 6 c. 4 d. 2 ------CORRECT ANSWER---------------a. 3 Overcurrent protection for interconnected electric power production source conductors connected to the supply side of the service disconnect means for a dwelling shall be located within ___ feet of the point where the electric power production source conductors are connected to the service. Select one: a. 3 b. 5 c. 2 d. 10 ------CORRECT ANSWER---------------d. 10 What is the VA input of a fully-loaded, 5 hp, 230-volt, single-phase motor? Select one:
a. 12,8 80 b. 746 c. 3, d. 6,440 ------CORRECT ANSWER---------------d. 6, A code letter D is marked on a motor nameplate. What is its locked-rotor kVA per horsepower? Select one: a. 4.0 - 4. b. 3.55 - 3. c. 0 - 3. d. 3.15 - 3.54 ------CORRECT ANSWER---------------a. 4.0 - 4. Determine the minimum size THW copper branch-circuit conductors the NEC® requires to feed a 3-phase, continuous duty motor that draws 70 amps per phase. Assume terminations are rated at 75ºC. Select one: a. 4 AWG b. 2 AWG c. 3 AWG d. 1 AWG ------CORRECT ANSWER---------------c. 3 AWG A feeder supplying two continuous duty, induction type, Design B, 208-volt, three-phase motors (one 10 hp and one 71/2 hp) shall have a minimum ampacity of ___ amperes. Select one: a. 62. b. 55 c. 68. d. 38.5 ------CORRECT ANSWER---------------a. 62.
e. 50 ------CORRECT ANSWER---------------c. 6 An RV campground has 150 campsites with electrical power. Twenty-five of the campsites are reserved as tent sites. How many sites are required to have a 30-amp, 125-volt receptacle? Select one: a. 0 b. 125 c. 150 d. 88 e. 25 ------CORRECT ANSWER---------------d. 88 Receptacles that provide shore power for boats shall be rated not less than ___ amperes. Select one: a. 20 b. 30 c. 40 d. 50 ------CORRECT ANSWER---------------b. 30 Supply cords for mobile homes shall be rated not less than ___ amperes. Select one: a. 100 b. 60 c. 50 d. 125 ------CORRECT ANSWER---------------c. 50 Overcurrent protection for feeders and branch circuits supplying electric vehicle supply equipment shall have a rating of not less than ___% of the maximum load of the electric vehicle supply equipment. Select one: a. 80
b. 200 c. 125 d. 100 e. 150 ------CORRECT ANSWER---------------c. 125 Lamps in cellulose nitrate film storage vaults shall be installed in rigid luminaires of the ___ type.I. glass-enclosed II. guarded III. gasketed Select one: a. I & III only b. I, II & III c. II & III only d. II only e. I & II only ------CORRECT ANSWER---------------a. I & III only A theater stage switchboard is used primarily to feed stage equipment and can contain ___, dimmers or relays with associated overcurrent protective devices, or overcurrent protective devices alone. Select one: a. fuses b. dimmers c. relays d. all of these ------CORRECT ANSWER---------------d. all of these A ___ is an assembly cable containing one male and two female cord connectors used to connect two loads to one branch circuit. Select one: a. tap box b. splitter c. transfer cable d. two-fer e. breakout assembly ------CORRECT ANSWER---------------d. two-fer
The power supply to the mobile home shall be a feeder assembly consisting of not more than one listed ___-ampere mobile power-supply cord with an integrally molded or securely attached plug cap or a permanently installed feeder. Select one: a. 60 b. 100 c. 30 d. 50 e. 20 ------CORRECT ANSWER---------------d. 50 Outdoor mobile home disconnecting means shall be installed so the bottom of the enclosure containing the disconnecting means is not less than ___ above finished grade or the working platform. Select one: a. 11/2 ft. b. 6 ft-7 in. c. 2 ft. d. 6 ft-6 in. e. 21/2 ft. ------CORRECT ANSWER---------------c. 2 ft. Switching devices shall be located at least ___ horizontally from the inside walls of the pool. Select one: a. 18" b. 5' c. 2' d. 4' ------CORRECT ANSWER---------------a. 18 All fixed metal parts that are within ___ feet horizontally of the inside walls of a permanently installed swimming pool must be bonded together. Select one: a. 10
b. 5 c. 20 d. 7 e. 8 ------CORRECT ANSWER---------------b. 5 A 120-volt receptacle located at ___ feet from the inside wall of a swimming pool must be GFCI protected. Select one: a. 19 b. 15 c. 10 d. all of these ------CORRECT ANSWER---------------d. all of these A wet-niche swimming pool luminaire is supplied by a 14 AWG flexible cord and protected with a 15-amp, GFCI breaker. The minimum size equipment grounding conductor required is ___ AWG. Select one: a. 10 b. 14 c. 8 d. 12 e. 16 ------CORRECT ANSWER---------------b. 14 No receptacle shall ever be permitted to be installed within ___ feet of the inside walls of a pool. Select one: a. 20 b. 18 c. 6 d. 15 ------CORRECT ANSWER---------------c. 6
b. provided with ground-fault circuit-interrupter protection for personnel c. provided with factory-installed ground-fault circuit-interrupter protection for personnel d. none of the these ------CORRECT ANSWER---------------c. provided with factory-installed ground-fault circuit-interrupter protection for personnel The maximum number of 15-amp receptacles permitted on a freestanding office partition is ___. Select one: a. 6 b. 13 c. 2 d. 10 ------CORRECT ANSWER---------------b. 13 Conductors that supply one or more arc welders shall be protected by an overcurrent device rated or set at not more than ___% of the conductor ampacity. Select one: a. 70 b. 200 c. 125 d. 50 e. 80 ------CORRECT ANSWER---------------b. 200 For PV systems, conductor ampacities must be correct if installed in ambient temperatures exceeding ___°F. Select one: a. 83 b. 78 c. 71 d. 86 ------CORRECT ANSWER---------------d. 86
A disconnecting means shall be provided for all ungrounded conductors derived from a stationary battery system with a voltage over ___ volts dc. Select one: a. 100 b. 60 c. 50 d. 30 ------CORRECT ANSWER---------------b. 60 Automatic transfer switches (ATS) for emergency systems shall be electrically operated and ___ held. Select one: a. mechanically b. manually c. automatically d. pneumatically e. electrically ------CORRECT ANSWER---------------a. mechanically The optional standby system wiring ___ be permitted to occupy the same raceways, cables, boxes, and cabinets with other general wiring. Select one: a. shall b. shall not ------CORRECT ANSWER---------------a. shall Branch-circuit conductors that supply a single motor used in a continuous duty application shall have an ampacity of not less than ___ of the motor's full-load current rating as determined by 430.6(A)(1). Select one: a. 190% b. 150% c. 50% d. 58% e. 125% ------CORRECT ANSWER---------------e. 125%
b. 802 c. 130 d. 114 e. 179 ------CORRECT ANSWER---------------c. 130 A 14 AWG THHN copper conductor is used between a motor starter and a remote start/stop station. What is the maximum size circuit breaker permitted for the motor short-circuit ground-fault protection that will also protect the 14 AWG conductor? Select one: a. 15 amp b. 10 amp c. 45 amp d. 60 amp ------CORRECT ANSWER---------------c. 45 amp Where the motor control circuit transformer rated primary current is less than 2 amperes, an overcurrent device rated or set at not more than ___% of the rated primary current shall be permitted in the primary circuit. Select one: a. 250 b. 167 c. 125 d. 300 e. 500 ------CORRECT ANSWER---------------e. 500 Determine the minimum size overload protection required for a 480-volt, 3- phase, 15 hp, continuous duty motor given the following information.* Design B * temperature rise - 40ºC* service factor - 1.12 * actual nameplate rating - 18 amps Select one: a. 23.4 amps b. 22.5 amps c. 18 amps d. 20.7 amps ------CORRECT ANSWER---------------d. 20.7 amps
For a nonautomatically started motor, the overload protection shall be permitted to be shunted or cut out of the circuit during the starting period of the motor if the device by which the overload protection is shunted or cut out cannot be left in the starting position and if fuses or inverse time circuit breakers rated or set at not over ___ percent of the full-load current of the motor are located in the circuit so as to be operative during the starting period of the motor. Select one: a. 130 b. 140 c. 11 5 d. 125 e. 400 ------CORRECT ANSWER---------------b. 140 Determine the maximum current setting permitted for overload protection for a motor that has a thermal protector integral with the motor, given the following information.* 71/2 hp - wound rotor type * two-phase, 4 wire, AC * 230 volts Select one: a. 32.3 amps b. 29.6 amps c. 26.6 amps d. 19 amps ------CORRECT ANSWER---------------b. 29.6 amps When service-entrance conductors exceed 1100 kcmil for copper, the required grounded conductor must be sized not less than ___ percent of the area of the largest phase conductor. Select one: a. 15 b. 12. c. 19 d. 25 ------CORRECT ANSWER---------------b. 12.
Under the optional method for a single-family dwelling, general loads beyond the initial 10 kW are calculated at a ___ percent demand factor. Select one: a. 40 b. 75 c. 50 d. 60 ------CORRECT ANSWER---------------a. 40 It shall be permissible to apply a demand factor of ___% to the nameplate ratings of 4 or more fastened-in-place water heaters in a multifamily dwelling. Select one: a. 50 b. 80 c. 90 d. 75 ------CORRECT ANSWER---------------d. 75 Where fixed multioutlet assemblies are employed, each ___ feet or fraction thereof of each separate and continuous length shall be considered as one outlet of not less than 180 volt-amperes where the connected appliances are unlikely to be used simultaneously. Select one: a. 1 b. 8 c. 10 d. 5 e. 6 ------CORRECT ANSWER---------------d. 5 A single-family dwelling unit has three ovens rated at 6, 8, and 3.5 kW; a cooktop rated at 6 kW, and a broiler rated at 3.5 kW. The minimum demand factor to be calculated for the ungrounded service entrance conductors is ___. Select one:
a. 18.6 kW b. 12.2 kW c. 30.1 kW d. 27.3 kW ------CORRECT ANSWER---------------b. 12.2 kW The minimum number of 120-volt, 15-amp lighting branch circuits required for a dwelling that has 70 X 30 ft. of livable space is ___. Select one: a. 5 b. 3 c. 2 d. 4 ------CORRECT ANSWER---------------d. 4 The demand factor for six residential clothes dryers in a multifamily dwelling unit is ___. Select one: a. 70% b. 80% c. 75% d. 60% ------CORRECT ANSWER---------------c. 75% In a dwelling, the minimum feeder neutral for a 5 kVA clothes washer/dryer would be ___ kVA. Select one: a. 5 b. 4. c. 3. d. 3.5 ------CORRECT ANSWER---------------d. 3. For track lighting installed in a retail store, a maximum of 2 feet of lighting track or fraction thereof shall be considered ___. Select one:
