Deck 14: Services Feeders and Equipment

Question 1

A(n) ____ minimum vertical clearance is required above finished grade for sidewalks, or from any platform or projection from which overhead conductors (of 150 volts, or less, to ground) might be reached.

A) 9-ft (2.7-m)
B) 10-ft (3.0-m)
C) 11-ft (3.3-m)
D) 12-ft (3.7-m)

Answer 1

B

Question 2

Ground-fault protection that functions to open the service disconnect will afford no protection from faults on the ____ of the protective element.

A) circuit side
B) panel box side
C) underside
D) line side

Answer 2

D

Question 3

Where 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 ____ of the area of the largest ungrounded supply conductor or equivalent area for parallel supply conductors.

A) 10½%
B) 12½%
C) 15½%
D) 18½%

Answer 3

B

Question 4

According to the NEC , live parts of electric equipment operating at 50 to 1000 volts, nominal, shall be guarded against ____ by approved enclosures.

A) water damage
B) overvoltage
C) accidental contact
D) phase transformations

Question 5

The alternating current phase arrangement on 3-phase busses are ____ from front to back, top to bottom, or left to right, as viewed from the front of the switchboard, switchgear, or panelboard.

A) A, B, C
B) C, B, A
C) 1, 2, 3
D) 3, 2, 1

Question 6

Vertical wiring clearances apply to ____.

A) commercial services
B) residential services
C) all electrical feeder and service installations
D) dwellings over six stories

Question 7

No secondary overcurrent protection is required for certain transformers 1000 volts, nominal, or less with currents of at least 9 amperes and a maximum primary overcurrent protection of ____.

A) 75%
B) 100%
C) 125%
D) 150%

Question 8

The connection between the grounded circuit conductor (neutral) and the equipment grounding conductor at the service is the ____.

A) main switching lead
B) main bonding jumper
C) central lead
D) transverse bridge

Question 9

Where rear access is required to work on nonelectrical parts at the back of enclosed equipment, a minimum working space of ____ horizontally is required.

A) 20 in.(508 mm)
B) 30 in.(762 mm)
C) 36 in.(914 mm)
D) 40 in.(1 m)

Question 10

According to the NEC , where a panelboard is supplied through a transformer, the overcurrent protection required by 408.36 shall be located on the ____ side of the transformer.

A) top
B) bottom
C) primary
D) secondary

Question 11

Equipment rated ____ amperes (or more) and over 6 ft (1.8 m) wide requires an entrance to and egress from the required working space at least 24 in.(610 mm) wide and 6½ ft (2.0 m) high at each end of the working space.

A) 700
B) 1000
C) 1100
D) 1200

Question 12

Overcurrent protection for transformers over ____ volts, nominal, is required.

A) 300
B) 500
C) 600
D) 1000

Question 13

Service equipment in other than dwelling units shall be legibly marked in the field with the ____.

A) average impedance
B) minimum current
C) maximum available fault current
D) maximum average current

Question 14

A structural ceiling may not ____.

A) contain any wiring
B) contain any lighting
C) be a suspended or drop type
D) contain ductwork

Question 15

A drip loop's lowest point has a minimum vertical clearance of ____.

A) 9 ft (2.7 m)
B) 10 ft (3.0 m)
C) 11 ft (3.3 m)
D) 12 ft (3.7 m)

Question 16

The ____ phase must be that phase having the higher voltage to ground on 3-phase, 4-wire, delta-connected systems.

A) A
B) B
C) C
D) D

Question 17

All panelboards shall have a rating not less than the ____ required for the load calculated in accordance with Part III, IV, or V of Article 220.

A) minimum feeder capacity
B) maximum feeder capacity
C) 50% of maximum feeder capacity
D) 50% of minimum feeder capacity

Question 18

One access means to a working space is permitted where the location provides ____.

A) a continuous and unobstructed exit
B) adequate sprinkler coverage
C) balcony exits
D) adequate overhead clearance

Question 19

Where ungrounded conductors are increased in size for any reason other than as required in 310.15(B) or 310.15(C), wire-type equipment grounding conductors (where installed) shall be increased in size ____, according to the circular mil area of the ungrounded conductors.

A) proportionately
B) inversely
C) directly
D) indirectly

Question 20

A ____ is a large single panel, frame, or assembly of panels with front- or rear-mounted switches, protective devices (overcurrent, etc.), buses, and, usually, instruments.

A) panelboard
B) switchboard
C) circuit cabinet
D) panel cabinet

Question 21

Live generator parts operating at more than ____ volts ac to ground shall not be exposed to accidental contact by unqualified persons.

A) 25
B) 50
C) 75
D) 100

Question 22

The maximum rating for overcurrent protection on a primary unit is ____.

A) 125%
B) 250%
C) 300%
D) 350%

Question 23

All mechanical elements used to terminate a grounding electrode conductor or bonding jumper to a grounding electrode shall be ____.

A) painted
B) waterproof
C) accessible
D) lubricated

Question 24

A system that supplies a ____ and is derived from a transformer rated no more than 1000 volt-amperes does not require a grounding electrode conductor.

A) Class A, EE, AE circuit
B) main branch circuit
C) secondary circuit
D) Class 1, 2, or 3 circuit

Question 25

Premises wiring (system) is defined as ____, including power, lighting, control, and signal circuit wiring together with all their associated hardware, fittings, and wiring devices, both permanently and temporarily installed.

A) interior and exterior wiring
B) interior wiring
C) exterior wiring
D) main service wiring