chapter 3 commercial test

R

"rubber-based", now it is called thermoset

Continuous

600 or less volt class is not rated for ____ operation.

Continuous

A ___ load is any load that is on for 3 hours or more.

3, 86

Allowable ampacities of 310.16 (B) (16) is based on not more than ____ current-carrying conductors in a raceway, cable, or earth based on an ambient temperature of _____ degrees F.

Load served

Branch circuit conductors are required to have an ampacity not less than the ____.

Is not

Compensation for voltage drop ___ generally required by the NEC.

Higher

Conductor material can withstand ____ temperatures than insulation.

90 degrees F

Conductors with -2 designation system are rated at ____ in wet and dry locations.

-2

Conductors with a ___ insulation designation have a higher ampacity in a wet location than do conductors without the designation.

False

If a conductor is installed so not more than 50% is in a cooler area and 50% is in a hotter ambient temperature, the ampacity determined in the cooler are can be used for the entire run.

78, 86, correction

If an ambient temperature along a raceway is less than ___C or higher than ____C the ampacity must be modified by a ___ factor.

70%

If nine current-carrying conductors are installed in one raceway for a length greater than 24inches, the allowable ampacity must be reduce to ____ .

N

Nylon outer covering

125%

Overcurrent protection for continuous loads must be sized at no less than ____ of the load.

1/0 AWG

The minimum size conductor to be run in parallel is ____.

True

The neutral conductor of a 3-wire circuit from a 3-phase, 4-wire system is required to be counted as a current-carrying conductor in a raceway or cable.

True

The proper size and type of conductor must be installed to comply with manufacturers installation instructions

Material, length, size

The resistance of a conductor is dependent on the ____, _____, and _____ of wire.

U

Underground use

5

Voltage drop cannot exceed ____%.

3, adjustment

Whenever there is a grouping of more than ___ current-carrying conductors exists, an ____ factor must be applied.

THWN

Which of the following two insulation types are more likely to soften when heated? THWN or XHHN.

Thermoplastic

____ insulation can be heated, melted, and reshaped. Stiffens at 14 degrees C (THHN, THHW, THWN, and TW)

X

cross-linked synthetic polymer

T

thermoplastic covering

W

wet locations

60

Equipment rated at 100 amp or less, conductors 14-1 awg is _____ degrees C.

7/8, 60

Exposed raceways or cables to the sun installed in contact with the roof or less than ____, ____F is to be added to the ambient temperature for application of the adjustment factor.

W=IxI(R)

Heat generated in a conductor over a long period of time is ____, expressed in watts.

H=IxI(t)

Heat generated in a conductor over a short period of time is ____., expressed in ampere-square seconds.

H

High temperature rating, each ___ = 15C temperature rating above 60 degrees C.

125

Hot water heaters of ____ gal or less are considered continuous loads with a rating of 125% of nameplate.

60 degrees

If conduits or cables are installed on or withing 7/8 in. of a rooftop with sunlight exposure, the following temperature must be added to the ambient temperature for the application of the correction factor: ____ F.

Conductor fill, derating

Spare conductors installed in a raceway are required to be counted for _____ and ____ purposes.

adjustment, correction

The NEC removed "derated" and "derating" in the same raceway to ____ and ____ factors.

310.106(D)

The article for all conductors to be insulated ____.

86, corrected

The conductors installed in an ambient temperature higher than ____ degrees C, the ampacity must be _____.

ambient heat, current flowing, adjacent current-carrying conductors

The insulation on a conductor will collect heat from the ____, ____, and _____.

10

The length of conductor operating at a higher temperature is not permitted to exceed ___ % of the total conductor length.

Ampacity

The maximum current, in amperes, that a conductor can carry continuously under the conditions of abuse without exceeding its temperature rating.

60, 75, 90

The maximum operating temperatures are ____, ___, ___ degrees C.

True

The neutral conductor of a 2-wire circuit from a 3-phase, 4-wire system is required to be counted as as a current-carrying conductor in a raceway or cable.

False

The neutral conductor of a 3-wire circuit from a 1-phase, 3-wire system is required to be counted as a current-carrying conductor in a raceway or cable.

Thermoplastic, thermoset

The two most commonly used insulations are ____ and ____.

5%

Total voltage drop on a circuit cannot exceed ____.

Thermoset

____ insulation can withstand higher and lower temperatures. Can never be reheated and reshaped. (RHH, RHW, XHH, XHHW)

Type XHHW

____ is 90 degrees C in dry, 75 in wet.

310.15(B)(16)

____ shows allowable ampacities of insulated conductors.