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.
