Deck 14: Services, Feeders, and Equipment

Question 1

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

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

Answer 1

accidental contact

Question 2

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

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

Answer 2

D

Question 3

Where ungrounded conductors are increased in size from the minimum size that has sufficient ampacity for the intended installation, 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

Answer 3

A

Question 4

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

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

Question 5

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 6

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 7

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 8

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

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

Question 9

Equipment rated ____ amperes (or more) and over 6 ft (1.8 m) wide containing overcurrent devices, switching devices, or control are governed by specific entrance and egress requirements.

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

Question 10

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

Question 11

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 12

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 13

Vertical wiring clearances apply to ____.

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

Question 14

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 set of ungrounded supply conductors or equivalent area for parallel supply conductors.

A) 10 1/2%
B) 12 1/2%
C) 15 1/2%
D) 18 1/2%

Question 15

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
B) 30 in
C) 36 in
D) 40 in

Question 16

A ____ 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
B) 10-ft
C) 11-ft
D) 12-ft

Question 17

A structural ceiling may not ____.

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

Question 18

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 19

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

A) 9 ft
B) 10 ft
C) 11 ft
D) 12 ft

Question 20

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

Question 21

Live generator parts operating at more than ____ volts 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 an 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

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

Question 25

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