level 1 quarter 4

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

whit is the neutral current for a 4-wire, 120/280V circuit, where L1 =20A, L2= 20A, and L3 = 20A?

0A

a minimum working space depth of ___ ft to live parts of equipment operating at 277 volts-to-ground is required where there are exposed live parts on one side and no live grounded parts on the other side

3

The required working space for access to live parts of equipment operating at 300 volts-to-ground, where there are exposed live parts on one side and grounded parts on the other side, is ___ ft

3.5

where equipment operating at 1,000 volts, nominal or less to ground and likely to require examination, adjustment, servicing, or maintenance while energized is required by installation instruction or function to be located in a space with limited access, the width of the working space shall be the width of the equipment enclosure or a minimum of ___ in, whichever is greater

30

the required working space for access to live parts of equipment operating at 300 colts-to-ground, where there are exposed live parts on both sides of the workspace is ___ ft

4

live parts of electrical equipment operating at ___ nominal, shall be guarded against accidental contact by approved enclosures or by suitable permanent, substantial partitions or screens arranged so that only qualified persons have access to the space within reach of the live parts

50V to 1,000V

all switchboards shall be located in dedicated spaces and protected from damage and, for outdoor installations, the space equal to the width and depth of the equipment, and extending from grade to a height of ___ ft above the equipment, shall be dedicated to the electrical installation

6

For equipment rated 1200A or more and over 6ft wide that contains over-current devices, switching devices, or control devices, there shall be one entrance to and egress from the required working space not less than 24inches. Wide and ____ ft high at each end of the working space.

6.50

conductor ampacity shall be determined using the _______ column of table 310.15(B)(16) for circuits rated 100 A or less or marked for 14 awg threw 1 awg conductors .

60 Celsius

Ohm's law demonstrates the relationship between circuit ___

Intensity, EMF, and resistance

For indoor installations, piping, ducts, leak protection apparatus, or other equipment foreign to the electrical installation shall not be installed in the dedicated space above a panelboard or switchboard.

True

NFPA 70E, standard for electrical safety in the workplace, provides guidance for working space about electrical equipment, such as determining severity of potential exposure, planning safe work practices, arc-flash labeling, and selecting PPE

True

The minimum height of working spaces about electrical equipment, switchboards, panel boards, or motor control centers operating at 1,000V, nominal, or less and likely to require examination, adjustment, servicing, or maintenance while energized shall be 6.5ft or the height of the equipment, whichever is greater, except for service equipment or panel boards in existing dwelling units that do not exceed 200A

True

a "raceway" is an enclosed channel designed expressly for the holding of wires, cables, or busbars, with additional functions as permitted in the code

True

communications wiring such as telephone, antenna, and CATV wiring within a building shall not be required to comply with the installation requirements of Chapters 1 thru 7, except where specifically referenced in chapter 8

True

soldered splices shall first be spliced or joined so as to be mechanically and electrically secure without solder and then be soldered

True

utilities may be subject to compliance with codes and standards covering their regulated activities as adopted under governments law or regulation

True

when conductors carrying current in the same direction are brought together, the electromagnetic fields attempt to push the conductors together

True

service equipment labeling in other than dwelling units shall not be required if an arc-flash label is applied in accordance with _______ industry practice .

acceptable

capable of being removed or exposed without damaging the building structure or finish, or not permanately closed in by the structure or finish of the builidng is known as ...

accessible (as applied to wiring methods)

separately installed pressure connectors shall be used with conductors at the _______ not exceeding the ampacity at the listed and identified temperature rating of the connector .

ampacities

compliance with the provision of the NEX will result in

an electrical system essentially free from hazard

.... means acceptable to the authority having jurisdiction

approved

installations of communications equipment that under the exclusive control of communications utilities, and located outdoors or in building spaces used exclusively for such installations .... covered by the NEC

are not

The ... has the responsibility for deciding on the approval of equipment and materials

authority having jurisdiction

unused openings other than those intended for the operation of equipment, intended for mounting purposes, or permitted as part of the design for listed equipment shall be

closed to afford protection substantially equivalent to the wall of the equipment

wires are considered .... if rendered inaccessible by the structure or finish of the building

concealed

to discharge a capacitor, all that is required is a ___ path between the terminals of the capacitor. The free electrons on the negative plate will then flow through the external circuit to the positive plate

conductive

A ... location may be temporarily subject to dampness and wetness

dry

when protecting equipment against damage from the weather during construction, minimum ... provisions provided in the international building code (IBC), and the international residential code for one and two family dwellings (IRC) can be referenced for additional information

flood

nonmandatory informative annexes contained in the back of the NEC book are ...

for information only not enforceable as a requirement of the NEC

the NEC is

for the practical safeguarding of persons and property

connectors and terminals for conductors more finely stranded than Class B and Class C, as shown in table 10 of chapter 9, shall be ... for the specific conductor class or classes

identified

All switchboards, switchgear, panelboards, and motor control centers shall be located in dedicated spaces and protected from damage, and outdoor installations shall be

installed in identified enclosures, protected from accidental contact by unauthorized personnel or by vehicular traffic, and protected from accidental spillage or leakage from piping system

equipment or materials included in a list of published by a testing laboratory acceptable to the authority having jursidiction are said to be ...

listed

all switchboard, panelboards, and motor control centers shall be

located in dedicated spaces and protected from damage

the authority having jurisdiction has the responsibility for

making interpretations of rules deciding upon the approval of equipment and materials waiving specific requirements in the NEC and permitting alternate methods and materials if safety is maintained

wooden plugs driven into holes in ... or similar materials shall not be used for securing electrical equipment

masonry concrete plaster

acceptable industry practices for equipment labeling are described in NFPA 70E, standard for electrical safety in the workplace . This standard provides specific criteria for developing arc-flash labels for equipment that provides ___ and so forth

nominal system voltage and incident energy levels arc-flash boundaries minimum required levels of PPE

conductors normally used to carry current shall be ... unless otherwise provided in this NEC

of copper or aluminum

This NEC covers the installation of .... for public and private premises, including buildings, structures, mobile homes, recreational vehicles, and floating builidngs

opitcal fiber cables electrical equipment raceways

on a 4-wire , delta-connected system where the midpoint of one phase winding is grounded , only the conductor or bus-bar having the higher phase voltage-to-ground shall be durably and permanently marked by an outer finish that is _______ in color

orange

The ___ of an ac generator contains the electromagnetic field, which cuts through the stationary conductor coils

rotor

when the NEC uses ... it means the identified actions are allowed but not required, and they may be options or alternative methods

shall be permitted

wiring shall be installed so that the completed system will be free from ... other than as required or permitted esewhere in the NEC

short cicuits ground faults connections to the earth

which of the following systems shall be installed and removed in accordance with the NEC requirements

signaling conductors, equipment, and raceways communications conductors, equipment and raceways electrical conductors, equipment and raceways

working space shall not be used for ___

storage

Each disconnecting means shall be legibly marked to indicate its purpose unless located and arranged so ___

the purpose is evident

entrances to rooms and other guarded locations containing exposed live parts shall be marked with conspicuous ___ forbidding unqualified persons to enter

warning signs

a single receptacle is a single contact device with no other contact device on the same ...

yoke


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