Electrical 310 review
A department store feeder (continuous load) supplies a lighting load of 103A. The minimum size overcurrent device permitted for this feeder is _____.
150A
The ampacity of 15 current-carrying 10 RHW aluminum conductors in a raceway in an ambient temperature of 75°F is ______.
16A
What's the ampacity of three current-carrying 10 TW conductors run in a cable located in an attic space where the ambient temperature reaches 120°F?
17.40A
What's the ampacity of nine 10 THW current-carrying conductors with on equipment grounding conductor in a PVC raceway located in an ambient temperature of 46°C?
18.40A
Conductor adjustment factors shall not apply to conductors in raceways having a length not exceeding ______ in.
24
The temperature rating associated with the ampacity of a ______ shall be selected and coordinated so as not to exceed the lowest temperature rating of any connected termination, conductor, or device.
conductor
The ampacity of six current-carrying 4/0 XHHW aluminum conductors installed in a ground floor slab (wet location) is _____.
144A
A 1,200A feeder is tapped (over 10 ft but less than 25 ft long) to supply a 225A main breaker panelboard having a 180A continuous load. What's the minimum size THHN copper feeder tap conductor that can be used?
600 kcmil
What size overcurrent device is required for a 45A continuous load? The circuit is in a raceway with 14 current-carrying conductors.
60A
A raceway contains the following: One 4-wire, multiwire branch circuit that supplies a balanced incandescent 120V lighting load; one 4-wire, multiwire branch circuit that supplies a balanced 120V fluorescent lighting load; two conductors that supply a receptacle; and one equipment grounding conductor. The system is 120/208V, three-phase. Taking these factors into consideration, how many of these conductors are considered current carrying?
9 conductors
In accordance with Article 310, temperature correction and adjustment factors are permitted to be applied to the ampacity for the temperature rating of the ______, if the corrected and adjusted ampacity does not exceed the ampacity for the temperature rating of the termination in accordance with the provisions of 110.14(C).
conductor
Where a portion of a feeder is connected at both its supply and load ends to separately installed pressure connections in accordance with 110.14(C)(2), it shall be permitted to have an allowable ampacity the sum of the continuous load plus the noncontinuous load.
not less than
In a 3-wire circuit consisting of two-phase conductors and the neutral conductor of a 4-wire, three-phase, wye-connected system, the common conductor ______ a current-carrying conductor.
shall be counted as
The ______ rating of a conductor is the maximum temperature, at any location along its length, which the conductor can withstand over a prolonged period of time without serious degradation.
temperature
The branch-circuit overcurrent device and conductors for fixed storage-type water heater having a capacity of 120 gallons or less shall be sized not smaller than 125 percent of the rating of the ______.
water heater
What's the ampacity of five 10 THWN-2 current-carrying conductors with an equipment grounding conductor in a PVC raceway located ½ in. above a roof, where the ambient temperature is 94°F?
18.56A
Conductors shall have their ampacity determined using the ______ column of Table 310.16 for circuits rated over 100A, or marked for conductors larger than 1 AWG, unless the equipment terminals are listed for use with higher temperature-rated conductors.
75
A raceway contains eight current-carrying conductors. What size conductor is required to feed a 20A noncontinuous lighting load in a dry location?
12 THHN
Branch-circuit conductors for fixed electric space-heating equipment and any associated motors shall be sized not smaller than ______ percent of the load.
125
The branch-circuit overcurrent device and conductors for fixed storage-type water heaters that have a capacity of 120 gal or less shall be sized not smaller than ______ percent of the rating of the water heater.
125
If a branch circuit supplies a single nonmotor-operated appliance, the rating of overcurrent protection shall not exceed ______ if the overcurrent protection rating is not marked and the appliance is rated 13.30A or less.
20A
A continuous load of 27A requires the circuit overcurrent device to be sized at ______.
35A
Where six current-carrying conductors are run in the same conduit or cable, the ampacity of each conductor shall be lowered to _____ percent of its ampacity.
80
Insulated conductors rated 600V with the letters "HH" in their designation have a ______ insulation rating.
90°C
What's the ampacity of three 4 THHN current-carrying conductors in EMT located 1½ in. above a roof, where the ambient temperature is 94°F?
91.20A
Feeder conductors shall be permitted to be sized at 100 percent of the continuous and noncontinuous load where a portion of the feeder is connected at both its supply and load ends to separately installed pressure connections.
True
When determining the number of current-carrying conductors, a grounding or bonding conductor shall not be counted when applying the provisions of 310.15(C)(1).
True
Type ______ insulated conductors shall not be subject to ampacity adjustment where installed exposed to direct sunlight on a rooftop.
XHHW-2
Overcurrent protection shall not exceed ______.
all of these
The ampacity adjustment factors of Table 310.15(C)(1)) do not apply to Type AC or Type MC cable without an overall outer jacket, if which of the following condition(s) is(are) met.
all of these
Conductors for general wiring not specifically permitted elsewhere in this Code to be covered or bare shall ______.
be insulated
There are four principal determinants of conductor operating temperature, one of which is _____ generated internally in the conductor as the result of load current flow, including fundamental and harmonic currents.
heat
In a 3-wire circuit consisting of two-phase conductors and the neutral conductor of a 4-wire, three-phase, ______ connected system, the common conductor is a current-carrying conductor and subject to the adjustment provisions of 310.15(C)(1).
wye-
A 2 TW conductor is installed in a location where the ambient temperature is expected to be 102°F. The temperature correction factor for conductor ampacity in this location is ______.
0.82
Feeder grounded conductors that are not connected to an overcurrent device shall be permitted to be sized at ______ percent of the continuous and noncontinuous load.
100
If a branch circuit supplies a single nonmotor-operated appliance, the rating of overcurrent protection shall not exceed ______ percent of the appliance rated current if the overcurrent protection rating is not marked and the appliance is rated over 13.30A.
150
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
For circuits rated 100A or less, when the equipment terminals are listed for use with 75°C conductors, the _____ column of Table 310.16 shall be used to determine the ampacity of THHN conductors.
75°C
If the circuit's overcurrent device exceeds ______, the conductor ampacity shall have a rating not less than the rating of the overcurrent device.
800A
In a 3-wire circuit consisting of two-phase conductors and the neutral conductor of a 4-wire, three-phase, wye-connected system, the common conductor is not a current-carrying conductor and not subject to the adjustment provisions of 310.15(C)(1).
True
Where a branch circuit supplies continuous loads, or any combination of continuous and noncontinuous loads, the rating of the overcurrent device shall not be less than the noncontinuous load plus 125 percent of the continuous load.
True
