Mike holt exam prep unit 6

What's the minimum size THHN conductor required for a 150A circuit breaker or fuse? 1/0 AWG 2/0 AWG 3/0 AWG 4/0 AWG

1/0 AWG

The ampacity of six current-carrying 4/0 XHHW aluminum conductors installed in a ground floor slab (wet location) is _____. 135A 144A 185A 210A

144A

What's the ampacity of 1/0 XHHW-2 conductors if the ambient temperature is 108°F? 139A 148A 213A 241A

148A

The ampacity of 15 current-carrying 10 RHW aluminum conductors in a raceway in an ambient temperature of 75°F is _____. 12A 16A 22A 30A

16A

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? 1/0 AWG 250 kcmil 500 kcmil 600 kcmil

600 kcmil

What size overcurrent device is required for a 45A continuous load? The circuit is in a raceway with 14 current-carrying conductors. 45A 50A 60A 70A

60A

What's the ampacity of an 8 THHN conductor when installed in a walk-in cooler (dry location) if the ambient temperature is 50°F? 40A 50A 55A 63A

63A

The ampacity for each of 10 current-carrying 6 THHW conductors installed in an 18-in. long conduit in a dry location having an ambient temperature of 39°C is _____. 40A 68A 75A 90A

68A

When four or more current-carrying conductors are bundled together for more than _____ in., the conductor allowable ampacity must be reduced according to the factors listed in Table 310.15(C)(1). 12 24 36 48

24

One of the purposes of conductor overcurrent protection is to protect the conductors against excessive or dangerous heat. True False

True

Terminals for equipment rated over 100A and pressure connector terminals for conductors larger than 1 AWG must have the conductor sized according to the 75°C temperature rating as listed in Table 310.16. True False

True

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? 13.50A 17.40A 18.40A 27.40A

18.40A

What size conductors (paralleled in two raceways) are required for an 800A breaker that supplies a 600A continuous load? 250 kcmil 300 kcmil 500 kcmil 600 kcmil

500 kcmil

The ampacity of a conductor can be different along the length of the conductor. The higher calculated ampacity can be used if the lower ampacity portion of the circuit is no more than 10 ft, or no more than 10 percent of the length of the higher ampacity portion of the circuit conductors, whichever is less. True False

True

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? 13.50A 17.40A 18.56A 27.40A

18.56A

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? 7 conductors 8 conductors 9 conductors 11 conductors

9 conductors

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). True False

False

The maximum overcurrent protective device size for 14 AWG is 15A, 12 AWG is 20A, and 10 AWG is 30A. This is a general rule, but it doesn't apply to motor or air conditioner loads according to 240.4(G). True False

True

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 _____. 0.71 0.82 0.88 0.96

0.82

A 1,200A feeder is tapped (maximum of 10 ft in length) to supply a 100A main breaker panelboard having a total calculated load of 100A. What's the minimum size THHN copper feeder tap conductor that can be used when the terminals are rated 75°C? 1 AWG 2 AWG 3 AWG 4 AWG

1 AWG

A raceway contains eight current-carrying conductors. What size conductor is required to feed a 20A noncontinuous lighting load in a dry location? 14 THHN 12 THHN 10 THHN 8 THHN

12 THHN

What size overcurrent device will be required for a feeder supplying a 100A continuous and a 100A noncontinuous load? 150A 200A 225A 250A

225A

What size feeder conductor will be required for a feeder supplying a 100A continuous and a 100A noncontinuous load? 2/0 AWG 3/0 AWG 4/0 AWG 300 kcmil

4/0 AWG

A continuous load of 27A requires the circuit overcurrent device to be sized at _____. 20A 30A 35A 40A

35A

The ampacity for each of nine current-carrying 10 THW conductors installed in a 20-in. long raceway is _____. 25A 30A 35A 40A

35A

What size conductor is required for a 70A breaker that supplies a 65A noncontinuous load? 8 AWG 6 AWG 4 AWG 3 AWG

4 AWG

What size conductor is required for a 90A breaker that supplies an 85A noncontinuous load where the terminals are rated 75°C? 8 AWG 6 AWG 4 AWG 3 AWG

4 AWG

What's the minimum size THHN conductor permitted to terminate on a 70A circuit breaker or fuse? 8 AWG 6 AWG 4 AWG 2 AWG

4 AWG

What size overcurrent protection will be required for a branch circuit supplying a 32A continuous nonlinear load? 40A 50A 60A 100A

40A

Overcurrent protective devices must be designed and rated to clear fault current and must have an adequate short-circuit interrupting rating for the available fault levels. If the minimum interruption rating isn't marked on the overcurrent protective device, according to the NEC the minimum for circuit breakers is _____ and _____ for fuses. 5,000A, 5,000A 5,000A, 10,000A 10,000A, 5,000A 10,000A, 10,000A

5,000A, 10,000A

What size conductor is required for a 70A breaker that supplies a 65A noncontinuous load where the terminals are rated 75°C? 8 AWG 6 AWG 4 AWG 3 AWG

6 AWG

What's the minimum size THHN conductor permitted to terminate on a 50A circuit breaker or fuse? 8 AWG 6 AWG 4 AWG 2 AWG

6 AWG

A 65A continuous load requires a _____ overcurrent device. 60A 70A 75A 90A

90A

If the ambient temperature is 71°C, the minimum insulation temperature rating a conductor must have and still have the capacity to carry current is _____. 60°C 90°C 105°C 120°C

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? 53.50A 67.40A 78.40A 91.20A

91.20A

The neutral conductor of a 3-wire wye circuit from a 4-wire, three-phase, wye system isn't considered a current-carrying conductor for the purpose of applying bundle adjustment factors. True False

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. True False

False

If the ampacity of a conductor doesn't correspond with the standard ampere rating of a fuse or circuit breaker, the next size up overcurrent protective device is permitted. This applies only if the conductors supply multioutlet receptacles for portable cord-and-plug-connected loads. True False

False

Which of the following describes Type TFN insulation? Solid or flexible stranded fixture wire Thermoplastic insulation with a nylon outer cover Suitable for dry and wet locations Solid or flexible stranded fixture wire having a thermoplastic insulation with a nylon outer cover

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

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 all of these

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 all of these

A(An) _____ THHN conductor is required for a 19.70A noncontinuous load if the ambient temperature is 75°F and there are nine current-carrying conductors in the raceway in a dry location. 14 AWG 12 AWG 10 AWG 8 AWG

12 AWG

What size THHN conductors are required to feed a 20A noncontinuous load when the conductors are in an ambient temperature of 120°F in a dry location? The circuit is protected with a 20A overcurrent device. 14 AWG 12 AWG 10 AWG 8 AWG

12 AWG

A department store feeder (continuous load) supplies a lighting load of 103A. The minimum size overcurrent device permitted for this feeder is _____. 110A 125A 150A 175A

150A

What's the ampacity of 10 THHN conductors if there are thirty-one conductors in the cross-sectional area of a wireway? 16A 18A 20A 25A

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? 13.50A 17.40A 18.40A 27.40A

17.40A

What size conductors (paralleled in three raceways) are required for a 1,200A breaker that supplies a 900A continuous load? 250 kcmil 300 kcmil 500 kcmil 600 kcmil

600 kcmil

There's a total of nine 10 THW conductors in a raceway. The system voltage is 120/208V, three-phase. One conductor is an equipment grounding conductor; four conductors supply a 4-wire, multiwire branch circuit for balanced electric-discharge luminaires; and the remaining conductors supply a 4-wire, multiwire branch circuit for balanced incandescent luminaires. Taking all these factors into consideration, how many of these conductors are considered current carrying? 6 conductors 7 conductors 9 conductors 10 conductors

7 conductors

SOW can be described as _____. thermoset suitable for damp and wet locations having 600V insulation all of these

thermoset suitable for damp and wet locations having 600V insulation all of these

What's the ampacity of three 4 THHN current-carrying conductors in EMT located ½ in. above a roof, where the ambient temperature is 94°F? 55.10A 67.40A 78.40A 91.20A

55.10A

What size THHN/THWN conductor is required for an air-conditioning unit if the nameplate requires a conductor ampacity of 34A? The terminals of all the equipment and circuit breakers are rated 75°C and the raceway is installed outdoors in a wet location. 14 AWG 12 AWG 10 AWG 8 AWG

10 AWG