Deck 17: Industrial Locations

Question 1

Knife switches rated more than ____, and at over 1000 amperes at 251 to 1000 volts, shall be used only as isolating switches and shall not be opened under load.

A) 1000 amperes at 250 volts or less
B) 1100 amperes at 200 volts or less
C) 1200 amperes at 250 volts or less
D) 1200 amperes at 200 volts or less

Answer 1

C

Question 2

Means shall be provided to disconnect all conductors in a building (or other structure) from the ____.

A) main feeder line
B) auxiliary panel board
C) primary panel board
D) service-entrance conductors

Answer 2

D

Question 3

The combined length of one primary plus one secondary conductor (excluding any portion of the primary conductor protected at its ampacity) shall not exceed ____.

A) 5 ft
B) 10 ft
C) 15 ft
D) 25 ft

Answer 3

D

Question 4

Cable tray systems should be ____.

A) water tight
B) insulated from frost damage
C) mounted at least 8 ft. above grade
D) corrosion resistant

Question 5

Barriers are required in all service-entrance motor-control centers to ____ and terminals from the remainder of the motor-control center.

A) isolate service busbars
B) connect the branch circuit
C) provide protection to the motor
D) isolate vertical sections

Question 6

A transformer's primary conductors shall have an ampacity at least ____ of the feeder conductors' overcurrent device rating.

A) one-third
B) one-half
C) three-quarters
D) two-thirds

Question 7

If the ungrounded supply conductors are larger than 1100 kcmil copper or 1750 kcmil aluminum, the supply-side bonding jumper shall have an area not less than ____ percent of the area of the largest ungrounded supply conductor or equivalent area for parallel supply conductors.

A) 10.5
B) 12.5
C) 12.75
D) 14.0

Question 8

Cartridge fuse and fuseholder overcurrent protection provisions are located in ____.

A) 240.12
B) 240.21
C) 240.60 and 240.61
D) 404.8 and 404.13

Question 9

A transformer vault door must be ____.

A) made of dual layer steel
B) equipped with fully engaged locks
C) installed with a door sill
D) accessible to all

Question 10

____ branch circuits shall be protected at the motor nameplate current rating.

A) Transformer
B) HVAC
C) Torque motor
D) Circuit breaker

Question 11

Overload is defined as operation of equipment in excess of normal, full-load rating, or of a conductor ____ that, when it persists for a sufficient length of time, would cause damage or dangerous overheating.

A) at 75% or of rated ampacity
B) in excess of rated ampacity
C) at 90% of rated ampacity
D) in excess calculated peak voltage

Question 12

To calculate the ampacity of conductors supplying several motors (feeder conductors), multiply the largest motor full-load current (FLC) rating by ____% and add the FLC ratings of all other motors (or loads) in the group.

A) 90
B) 100
C) 115
D) 125

Question 13

Motor circuits rated 1000 volts, nominal, or less, shall have a disconnecting means with an ampere rating of at least ____% of the motor's full-load current rating.

A) 75
B) 90
C) 115
D) 150

Question 14

Wherever such an arrangement is practicable, transformer vaults shall be located so that ____.

A) they are directly under the main service line entrance
B) all junction boxes are adjacent to them on a vertical line
C) ventilation to outside air does not rely on flues or ducts
D) all junction boxes are adjacent to them on a horizontal line

Question 15

A tap conductor is a ____ that exceeds the value permitted for similar conductors protected as otherwise described in 240.4.

A) conductor having overcurrent protection ahead of its point of supply
B) switch that redirects service to a branch having a total capacity
C) spliced line having an average peak load
D) dual-phase system having branches to an overload system

Question 16

A ____ is the minimum size allowed if the overcurrent protection on the tap conductor's line side is 600 amperes.

A) 100-ampere rated conductor
B) 200-ampere rated conductor
C) 300-ampere rated conductor
D) 400-ampere rated conductor

Question 17

The tap conductor's ampacity shall not be less than the ____ on the circuits it supplies.

A) inverse of the total load
B) combined calculated loads
C) total capacity for the circuit breaker
D) rating for the combined wires

Question 18

Where an orderly shutdown is required to minimize the personnel/equipment hazard(s), a system of coordination based on the following two conditions is permitted: (1) coordinated short-circuit protection and (2) ____.

A) overload indication based on monitoring systems or devices
B) coordinated service (a single main feeder line)
C) a single switching source
D) integrated circuitry

Question 19

If a single raceway supplies an equipment grounding conductor, only one ____ equipment grounding conductor is required.

A) 3/0 AWG copper
B) 4/0 AWG copper
C) 5/0 AWG copper
D) 6/0 AWG copper

Question 20

A 60-ampere rated conductor is the minimum size allowed if the overcurrent protection on the tap conductor's line side is ____.

A) 300 amperes
B) 500 amperes
C) 600 amperes
D) 800 amperes

Question 21

Where multiple power supplies serve the same dc system, the dc side of each power supply shall have a ____.

A) disconnecting means
B) suitable ground
C) removable conductor
D) removable fuses

Question 22

Conductors used in the secondary circuit of electric welders shall have ____.

A) polymer insulation
B) flame-retardant insulation
C) hybrid insulation
D) terminal busbars

Question 23

If a crane, hoist, or monorail hoist operates above readily combustible material, specific requirements shall apply to ____.

A) capacitors
B) resistors
C) overload protection
D) receptacle placement

Question 24

The capacitor circuit conductor's ampacity shall be at least ____% of the capacitor's rated current.

A) 100
B) 125
C) 135
D) 150

Question 25

Minimum ampacity of arc welder conductors supplying a group of welders shall be based on ____ as determined in 630.11(A)

A) total branch capacity
B) aggregate load
C) individual resistances
D) individual currents