NEC 3&4

Pataasin ang iyong marka sa homework at exams ngayon gamit ang Quizwiz!

The equivalent of _____ is the maximum allowed between pull points.

four quarter bends (360 degrees total)

All cut ends of IMC and RMC must be

reamed

Volume shall be marked on all nonmetallic boxes and boxes with a volume of ___ cubic inches or less

100

Flexible metal conduit (FMC) is a raceway of circular cross section made of --------

Helically wound formed and interlocked metal strips

A multiconductor cable, optical fiber cable, or flexible cords of two or more conductors is treated as ____ for percentage conduit fill areas calculations

a single conductor

Surface nonmetallic raceways and their fittings must be designed so that sections can be mechanically coupled together and installed without subjecting the wires to ____

abrasion

Electric metal tubing (EMT) provides protection from ____

all but severe physical damage

Exposed runs of Type AC cable installed on the underside of joists must be supported at ____

every joist

Electrical installation openings that penetrate into or through fire-resistant-rated structures must be

firestopped

The maximum number of conductors applies only if the box does not contain any

fittings or devices

NEC identifies ______ types of rigid PVC conduit.

five

Type AC cable must have a bending radius at least ______ times the diameter of the cable

five

Cables running horizontally or diagonally are considered supported and secured when passing through a

framing member

Cables not installed on the face do not require

guard strips or running boards

Cable installed under a building must be _______ unless the wiring method is Type MC or Type MI cable that is identified for diret burial

in a raceway

Where a box contains both straight and angle or U pulls or straight pulls and splices calculate each type of pull ______ to find the dimension

individually

Equipment grounding conductors or equipment bonding jumpers entering a box count as ______

one conductor

Volume in boxes can be increased by using _____ rings, domed covers, extension rings, or similar items

plaster (mud)

A key provision found in most of the cable articles states that the cable must not be installed where subject to

pysical damage

No requirement specifies the depth of a box, unless a _______

raceway enters the back of the box

Box calculations for 4 AWG and larger conductors (under 600 volts) are performed based on the

size and number of raceways

Electrical metallic tubing must not be

threaded

Wireways are _______ housing and protecting electric wires ( and cables)

troughs with hinged or removable covers for

A cable assembly's ___ conductor can be used as a switch loop (leg) in single-pole three-way and four-way switch installations, even though it is an ungrounded (hot) conductor.

white or gray

Wire connectors pigtails locknuts bushings raceway connectors grounding screws and equipment bonding jumpers are not factors when calculating

box fill

Rigid metal conduit (RMC) is a thread-able raceway of ______ designed for the physical protection and routing of conductors and cables

cable abrasion

Cable connectors with a ______ outside the box are not counted when determining the number of conductors

clamping mechanism

Underfloor raceway dead ends must be

closed

Type AC cable shall have a

flexible metal tape armor

PVC bends must be made so that the conduit remains undamaged and the internal diameter of the conduit is

not reduced

Supporting screws for nonmetallic boxes must be mounted ____

outside of the box

The minimum approved electrical trade size for EMT is ____ inches

.5

Holes must be bored so that the edge of the hole is at least

1 1/4 inch

The minimum box width for U pulls must include ____

12 in. between raceways plus the thickness of the two raceways

Grounding conductors are required for circuits over ____ amperes

20

What is the angle pull for a raceway in the vertical dimension where the trade size of the largest raceway is 4 and the sum of the other raceways in the same row on the same wall is 5?

29 inches

A luminaire that weighs more than _______ pounds shall be supported independently of the outlet box, unless the outlet box is listed and marked on the interior of the box to indicate the maximum weight the box shall be permitted to support.

50

Half-round and flat-top raceways not over 4 inches in width must be covered by _____ or mor of concrete (or wood)

75 inches

A 3x2 inch device box 2.5 in deep has a volume of ___ cubic inches

12.5

Multiconductor cord or cable used to support a box must be protected in an approved manner so that the conductors are not subjected to

strain

Nonmetallic-sheathed cable not fastened to the box must be secured within ___ in. of the box.

8

________ or fewer luminaire wires (smaller than 14 AWG) and an equipment grounding conductor can be omitted fro box fill calculations where they enter a box from a domed luminaire (or similar canopy) and terminate within that box

four

____ in the ends of larger conduits (2 to 6 inches) can prevent conduit collapses or other deformities

installing PVC plugs

A group of conductors that fit into one conduit may not fit into another type because the ___ of different types of conduit vary

internal diameters

Generally ungrounded (hot) conductors can be any color except _____

white, gray, green, or green with yellow stripes

Article 100 defines raceway as a _____ designed expressly for holding wires, cable or busbars

enclosed channel of metallic (or nonmetallic) materials.

The definition for intermediate metal conduit (IMC) and rigid metal conduit (RMC) is _____

essentially the same

Contact of dissimilar metals (except for the combination of aluminum and steel) should be avoided wherever possible to lessen the potential for

galvanic action

Raceways installed within drop ceilings must

have secure support provided by the support wires and associated fittngs

Inspection of the connections between luminaire conductors and circuit conductors must be possible without ____

having to disconnect any part of the wiring

Nonmetallic sheathed cable passing through holes in metal framing must be protected by -------- covering all metal edges

listed bushings (or grommets)

Ducts used to transport dust, loose stock or flammable vapors shall not contain ___ of any type

wiring systems

The weight supported by any single conduit shall not exceed ___ pounds

20

What is the angle pull for a raceway in the horizontal dimension where the trade size of the largest raceway is 3 and the sum of the other raceways in the same row on the same wall is 4?

22 inches

_______ are permitted inside conduit bodies if the manufacturer durably and legibly marked the cubic inch capacity on the conduit body

Splices, taps, or devices

Protection is required for cables located within 6 ft (measured both vertically and horizontally) of the ________

attic entrance

Bends must be made so that the conduit or tubing remains undamaged with its internal diameter

basically undiminished

A widely accepted practice is to identify 3-phase ungrounded (hot) conductors as ____ in 208/120 volt, 4 wire, wye-connected systems.

black, red and blue

Cover measurement commences at the top surface of any direct burial wiring method and ends at the ____ of the finished grade's top surface

closest point

Raceway fill calculations are a prerequisite in _____ needed for particular circuits.

determining the size of raceway

The length of a straight pull for multiple raceways must be at least ___ times the trade size (metric designator) of the largest single raceway

eight

Snap switches (including dimmer switches) must be connected to a(n) ______ and must also provide a means to connect metal faceplates to the equipment grounding conductor, even if a metal faceplate in not installed

equipment grounding conductor

A header is a transverse raceway ____

for electric conductors, providing access to predetermined cells of a cellular metal floor

Liquidtight flexible metal conduit (LFMC) is a raceway of circular cross section having a(n) _________ over an inner flexible metal core

out liquidtight, nonmetallic sunlight resistant jacket

Conduit body support must be ________

rigid and secure

Splices and taps are permitted within surface metal raceway having a removable cover that

remains accessible after installation

Where multiple rows of raceways enter a box, calculate each row separately and use the ____

single row that provides the maximums distance


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