Conductor Sizing and Protection Calculations.

The minimum size copper conductor permitted for voltage ratings up to 2,000V shall be _____ AWG.

14 AWG.

What size branch circuit is required for a 2,500W, 240V water heater?

15A

What's the ampacity of 10 THHN conductors if there are thirty-one conductors in the cross-sectional area of a wireway?

16A.

What's the adjusted ampacity of 10 THHN conductors when nine current-carrying conductors are installed in a raceway or cable?

28A.

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.

Feeder grounded conductors shall be permitted to be sized at _____ 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.

100.

The branch-circuit overcurrent device and conductors for fixed storage-type water heater having a capacity of _____ gallons or less shall be sized not smaller than 125 percent of the rating of the water heater.

120.

What size feeder conductor will be required for a feeder supplying a 100A continuous and a 100A noncontinuous load?

4/0 AWG.

What size overcurrent protection will be required for a branch circuit supplying a 32A continuous nonlinear load?

40A

What's the ampacity of four current-carrying 8 THHN conductors installed in an ambient temperature of 90°F?

42A.

Branch-circuit conductors for fixed electric space-heating equipment and any associated motors shall be sized not smaller than 150 percent of the load.

False.

The neutral conductor of a balanced 4-wire, three-phase wye circuit that's more than 50 percent loaded with nonlinear loads (electric-discharge lighting, electronic ballasts, dimmers, controls, computers, laboratory test equipment, medical test equipment, recording studio equipment, and so forth) isn't considered a current-carrying conductor for the purpose of applying bundle adjustment factors.

False.

Conductors for general wiring not specifically permitted elsewhere in this Code to be covered or bare shall _____.

be insulated.

A(An) _____ conductor that carries only the unbalanced current from other conductors of the same circuit shall not be required to be counted when applying the provisions of 310.15(C)(1).

neutral.

On a 4-wire, three-phase wye circuit where the major portion of the neutral load consists of _____ loads, the neutral conductor shall be considered a current-carrying conductor.

nonlinear.

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.

THHN can be described as _____.

thermoplastic insulation with a nylon outer cover having a maximum operating temperature of 90°C.

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.

Which of the following describes Type TFN insulation?

Solid or flexible stranded fixture wire having a thermoplastic insulation with a nylon outer cover.

What size conductor and overcurrent device are required for a 7,500W, 240V fixed electric space heater that has a 3A blower motor with 75°C terminals?

45A overcurrent device and an 8 AWG conductor.

What's the ampacity of 1/0 THHN conductors when there are four current-carrying conductors installed in a raceway in a dry location?

136A.

The neutral conductor that carries only the unbalanced current from a 3-wire 120/240v circuit or 4-wire, 120/208v three-phase wye circuit, is considered a current-carrying conductor for the purpose of applying the adjustment factors of Table 310.15(C)(1).

False.

Feeder tap conductors not over 25 ft in length are permitted, provided the _____.

ampacity of the tap conductors isn't less than one-third the rating of the overcurrent device protecting the feeder conductors being tapped. tap conductors terminate in a single circuit breaker or set of fuses that limit the load to the ampacity of the tap conductors. tap conductors are suitably protected from physical damage.

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.