Unit 11: General Practice Flashcards
Apply learned concepts to problem-solving exercises, identify knowledge gaps, and reinforce understanding through repetition.
Fill in the blank:
PVC conduit shall be securely fastened within ________ of each outlet box, junction box, device box, conduit body, or other conduit termination box.
3 feet
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A hazardous location where easily ignitable fibers or materials producing combustible flyings are handled, manufactured, or used, but where they are not likely to be in suspension in the air in quantities sufficient to produce ignitible mixtures is recognized as a ________ location in the NEC®.
Class III
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A copper-clad steel rod type grounding electrode shall be at LEAST ________ in diameter.
5/8 in.
Fill in the blank:
Given: A single-phase, 120/240-volt service of a single family dwelling has a chain-link metal fence opposite exposed live parts of the service equipment. The required depth of the working space in front of the service equipment must be at LEAST ________.
3 feet
Fill in the blank:
Tap conductors for a recessed luminaire shall be in a suitable raceway or Type AC or MC cable having a length not to exceed ________.
6 feet
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Where exposed Type NM cable passes through a floor, the cable shall be protected from physical damage by an approved means extending at LEAST ________ above the floor.
6 in.
When used as a direct buried cable, which of the wiring methods is permitted for use to supply a water well pump located 50 feet from a dwelling?
Type UF cable
Fill in the blank:
The supply to a portable switchboard on a stage shall be by means of listed extra-hard usage cords or cables. Single Conductor portable supply cable sets used for this purpose shall not be smaller than ________.
2 AWG
Fill in the blank:
The MINIMUM clearance for overhead feeder conductors, less than 1,000 volts, that pass above commercial areas subject to truck traffic is ________.
18 feet
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In regard to fixed electric space-heaters, factory assembled non heating leads of heating cables, if any, shall be at LEAST ________ in length.
7 feet
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Where the heating, air-conditioning or refrigeration equipment is installed on the roof of a commercial, industrial, or a multifamily apartment building, a single phase, 125-volt, 15- or 20- ampere rated receptacle outlet shall be located ________.
on the same level and within 25 ft. of the equipment
Given: An existing 150 kVA transformer with a 208Y/120-volt, 3-phase, secondary has a full load current of 220 amperes per phase. What approximate additional single-phase load, per phase, may be added to the secondary side of the transformer?
196 amperes
I = power I/E x 1.732 = 150 x 1000/208 x 1.732 = 150,000/360 = 416 amperes FLC
416 amperes (available FLC) – 220 amperes (existing load) =
196 amperes
Fill in the blank:
The conductors in multiconductor portable cables, of over 600 volts nominal, used to connect mobile equipment and machinery, shall be at LEAST size ________ copper or larger and employ flexible stranding.
12 AWG
Fill in the blank:
In metal raceways or enclosures, all conductors of feeders using a common neutral shall be enclosed within the same raceway or enclosure, with a MAXIMUM of ________ sets of 3-wire feeders permitted to utilize a common neutral.
three
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When installing surface-type metal panelboards, cabinets, disconnects or meter socket enclosures in damp or wet locations they shall be mounted so there is at LEAST ________ airspace between the enclosure and the wall or other supporting surface.
¼ in.
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On a 4-wire, 3-phase, wye circuit where more than ________ of the load consists of nonlinear loads such a fluorescent lighting, there are harmonic current present in the neutral conductor and the neutral conductor shall be considered to be a current-carrying conductor.
50%
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Where direct-buried conductors emerge from below grade and extend up a pole, the conductors must be protected by raceways up to a height of 8 feet above finished grade and in no case shall protection be required to exceed ________ below finished grade
18 in.
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Given: After all demand factors have been taken into consideration, a small office building with a single-phase, 120/240-volt electrical system has a demand load of 35,000 watts. The MINIMUM size copper conductors with THW insulation required for the ungrounded (line) service entrance conductors is ________.
1/0 AWG
I = 35,000 VA/240 volts = 145.8 amperes
Size 1/0 THW CU conductors with an ampacity of 150 amperes should be selected from Table 310.16.
Fill in the blank:
According to the NEC®, the ampacity of a conductor is the current, in amperes, that the conductor can carry continuously under the conditions of use without exceeding its ________.
temperature rating
What is the requirement when a building or structure receives more than one service from the local utility company?
A permanent plaque shall be installed at each service disconnect location denoting all other services.
Fill in the blank:
In Class I, Division 1 locations, all threaded conduit and fittings referred as National Standard Pipe Taper (NPT) thread that are entries into explosion proof equipment shall be made up with at LEAST ________ fully engaged threads.
five
Except as otherwise permitted in the NEC®, where the service entrance conductors for a commercial building or an industrial facility are size 350 kcmil aluminum with XHHW insulation, what MINIMUM size copper grounding electrode conductor is required?
2 AWG
Fill in the blank:
Where a wall-mounted central vacuum system is cord-and-plug connected to a single-phase, 125-volt, 20-ampere receptacle located in an attached garage of a residence, the receptacle shall be provided with ________ protection.
only GFCI
Fill in the blank:
For track lighting in other than dwelling units, or guest rooms of hotels and motels, a load of ________ shall be calculated for every two (2) feet of lighting track or fraction thereof.
150 VA
