5th year Exam #2
What minimum size THHN copper conductors are permitted to be run as the feeder conductors, where the feeder is three-phase 120/208-volts, and is protected by the maximum standard size overcurrent protective device(s) permitted by the Code, where run in EMT through an area with an ambient temperature of 47 degrees Celsius; the feeder supplies 35-amperes of 3-phase, fluorescent lighting load, and 27-amperes of three-phase, electric heating load?
#1, #2, #3, #4
What minimum size THHN copper conductors are permitted to be run as the feeder conductors, where the feeder is three-phase 120/208-volts, and is protected by the maximum standard size overcurrent protective device(s) permitted by the Code, where run in EMT through an area with an ambient temperature of 47 degrees Celsius; the feeder supplies 46-amperes of 3-phase, fluorescent lighting load, and 27-amperes of three-phase, electric heating load?
#1, #2, #3, #4
The bonding jumper required to connect the equipotential planes to the electrical grounding system for agricultural buildings shall be a __________ or larger?
#10 #8 #6 #4
Where a 4 kVA, single-phase, two-wire, AC transformer rated 480/208-volts is protected on the primary side only (when the protective device(s) are sized at the maximum standard size permitted by the Code), the minimum size THHN conductors permitted on the secondary side of the transformer in order to be considered protected by the overcurrent device on the primary side, are _____________, where all equipment is rated for use at 75 degrees Celsius?
#14 #12 #10 #8
The minimum size THHN feeder conductors permitted to be protected by a 700-ampere overcurrent device(s) when six conductors are paralleled per phase are ____________?
#2 #1 1/0 2/0
What is the minimum size THWN-2 that may be used as the branch circuit conductors, when the maximum standard size overcurrent device(s) permitted to be used for the branch circuit, short-circuit, ground-fault protective device for a roof-top unit at the time of the initial installation are used, all equipment is rated for use at 75 degrees Celsius, and the rooftop-unit nameplate contains the following information: 3-phase; 480-volts; compressor FLA: 37 amperes, three-phase; unit heater: 6.4 kW, three-phase; fan motor: 5 amperes, three-phase; MCA: 60 amperes max OCPD: 90 amperes?
#2, #3, #4, #6
What is the minimum size THWN-2 that may be used as the branch circuit conductors, when the maximum standard size overcurrent device(s) permitted to be used for the branch circuit, short-circuit, ground-fault protective device for a roof-top unit at the time of the initial installation are used, all equipment is rated for use at 75 degrees Celsius, and the rooftop-unit nameplate contains the following information: 3-phase; 480-volts; compressor FLA: 37 amperes, three-phase; unit heater: 8 kW, three-phase; fan motor: 6.38 amperes, three-phase; max OCPD: 90 amperes?
#2, #3, #4, #6
A metallic 4" x 2-1/8" square box is installed; the box is covered with a blank cover plate and all cables are secured to the box with external cable clamps. Two 14-2 NM-B cables and one 14-3 NM-B cable enter the box and are spliced together. What is the maximum number of 12-2 NM-B cables permitted by the Code to be added to the enclosure?
1 2 3 4
What minimum size EMT is required by the NEC, when EMT is run from a panelboard(cabinet) to a pull-box as part of a complete conduit system, where there will be four, #6 THHN conductors, and three #6 THWN-2 conductors installed in the EMT?
1-1/2" 1-1/4" 1" 3/4"
What minimum size RMC would the NEC require for the installation of six, #10, XHHW-2 conductors, three, #12, XHHW-2 conductors, and two, #14 XHHW-2 conductors?
1-1/4" 1" 3/4" 1/2"
What minimum size Schedule 80 PVC is required by the NEC to provide physical protection for a 2/0 bare conductor, when run as a grounding electrode conductor?
1/2" 3/4" 1" 1-1/4"
Where an existing 3/4" EMT contains eight, #12 THWN copper conductors, what is the maximum number of #14 THWN conductors that may be added without exceeding the permitted fill?
12 11 10 9
What is the maximum number of multi-conductor control and signal cables permitted to be installed in a solid-bottom cable tray 24-inches wide, and 9-inches deep, when the outside diameter of the cable is .898 inches?
137 136 91 90
What minimum size branch circuit NM-B cable is required to supply an air-conditioning heat pump with the following nameplate information: single-phase, with a voltage rating of 115/230-volts, an RLA of 15.2 amperes, and a maximum OCPD rating of 25 amperes?
14-2 NM-B 12-2 NM-B 12-3 NM-B 10-2 NM-B
The maximum number of #12 THHW conductors that are permitted to be pulled directly through (without splices) a standard 1" LB, which is installed in a 3/4" run of RMC is __________?
16 14 12 10
What minimum standard size solid-bottom cable tray would the NEC require for the installation of eight, three-conductor, 3/0 cables which have an outside diameter of 1.8 inches?
18" 20" 24" 30"
What minimum size RMC does the Code permit you to run between a cabinet and an auxiliary gutter, when the RMC is 18-inches long, and contains 24, #10 THWN-2 conductors?
2" 1-1/2" 1-1/4" 1"
What minimum size Schedule 80 PVC is permitted for the installation of four, 250 kcmil THHW conductors, and one, 1/0 bare equipment grounding conductor?
2" 2-1/2" 3" 3-1/2"
What minimum size EMT is required by the NEC, when the EMT is installed as a complete conduit system, and contains six, #2 AWG THHW, two, #1 AWG THHW conductors, and one, #4 AWG THHW conductor, where all conductors are compact aluminum?
2-1/2" 2" 1-1/2" 1-1/4"
What is the minimum length the NEC requires for a pull-box where a three-inch run of IMC is installed for a straight pull, the conductors are #4 AWG or lager, and are spliced in the enclosure?
24" 20" 18" 12"
What is the ampacity of a #10 THHN copper conductor?
25 amperes 30 amperes 35 amperes 40 amperes
What minimum standard size metal wireway is required for the installation of four, 500 kcmil, THHW conductors, and three, 250 kcmil, THHW conductors, when the length of the run is 100-feet, and there is three, ninety-degree factory bends installed?
3" x 3" 4" x 4" 5" x 5" 6" x 6"
What minimum size Schedule 80 PVC is required for a surface mounted panelboard (cabinet) in the the garage of a single-family dwelling unit, where the cabinet is surface mounted, and you have a 24-inch straight section of schedule 80 run vertically from the top of the cabinet [meeting all of the conditions of 312.5(C), Exception #1], and the schedule 80 PVC is there to provide physical protection for the cables between the cabinet and the joists; the cables run in the conduit will be 4-12/2 NM-B cables with outside dimensions of .38" x .633", and 4-14/3 NM-B cables having an outside diameter of .65"?
3-1/2" 3" 2-1/2" 2"
The minimum size THHN feeder conductors permitted to be protected by a 1000-ampere overcurrent device(s) when four conductors are paralleled per phase are ____________?
3/0 4/0 250 kcmil 300 kcmil
What minimum size EMT would be required by the NEC, when EMT is run from one enclosure to another for a distance of 110' as part of a complete conduit system, where there will be two, 12/2 NM-B cables pulled through the EMT (the cables have outside dimensions of .38" x .633")?
3/4" 1" 1-1/2" 2"
What minimum size RMC is required by the NEC for the installation of two, three-phase, 460-volt, motor branch-circuits, when they are installed in the same conduit, where one circuit consists of #4, THWN-2 conductors, and the other consists of #2, THWN-2 conductors?
3/4" 1" 1-1/4" 1-1/2"
The minimum size THHN feeder conductors permitted to be protected by a 800-ampere overcurrent device(s) when two conductors are paralleled per phase are ____________?
350 kcmil 400 kcmil 500 kcmil 600 kcmil
What are the minimum dimensions required by the NEC for a pull-box where you have two conduits entering a box on each of two adjacent sides, where the conduits are 4" and 3-1/2", and all conductors are #4 or larger?
36" x 36" 30" x 30" 24" x 30" 24" x 24"
What is the maximum number of #2 THHW, compact conductors that the NEC permits you to install in 1-1/2" EMT where run as part of a complete conduit system?
4 5 6 7
What is the maximum number of multi-conductor control and signal cables permitted to be installed in a ventilated-trough cable tray 12-inches wide, and 4-inches deep, when the outside diameter of the cable is .799 inches?
45 46 47 48
Where two pieces of switchgear are installed directly across from each other in an electrical room, and they are rated three-phase, 277/480-volts, and three-phase, 120/208-volts respectively, what is the minimum work space (total) required between the two pieces of switchgear?
5 feet 4 feet 3.5 feet 3 feet
What is the minimum distance required between the back wall of a single-family dwelling unit clothes closet, and the nearest part of a recessed LED luminaire that is totally enclosed, installed in the closet ceiling?
6 inches 12 inches 16 inches 18 inches
What is the minimum width of the working space for a three-phase, 277/480-volt panelboard, installed in a boiler room?
60 inches 48 inches 36 inches 30 inches
An existing 1-1/2" EMT contains twelve, #8, XHHW conductors; what is the maximum number of #8, THHN conductors that the NEC permits you to add to this existing raceway without exceeding the permitted fill?
8 7 6 5
What is the maximum number of #12, THHN copper conductors permitted by the NEC to be installed in 1/2" ENT?
8 9 10 11
What minimum standard size solid-bottom cable tray would the NEC require for the installation of four, three-conductor, 750 kcmil cables which have an outside diameter of 2.90 inches?
8" 9" 12" 16"
Where a flexible connection is required to supply power for a hot tub installed on the deck of a single-family dwelling, from an enclosure located on the outside of the dwelling unit, which of the following would be an acceptable wiring method for this connection?
NM-B cable routed inside of flexible non-metallic conduit MC cable where a corrosion-resistant jacket is provided over the metallic covering, and the metallic covering is impervious to moisture SE cable UF cable listed as sunlight resistant
A circuit breaker rated 120/240-volts, shall be permitted to be applied in a solidly grounded, 120/208-volt, three-phase, three-wire system.
True False
A circuit breaker rated 240/480-volts, shall be permitted to be applied in a solidly grounded, 480-volt, three-phase, three-wire system.
True False
Enclosures for overcurrent devices are permitted to be mounted horizontally where the circuit breakers clearly indicate whether they are in the open "off" or closed "on" position, and when operated vertically, the "up" position of the handle shall be the on position.
True False
