Residential and Other Calculations

Question 1

The maximum current in amperes that a conductor can carry continuously under the conditions of use without exceeding its temperature rating is known as its _____.
Answer 1: short-circuit rating
Answer 2: ground-fault rating
Answer 3: ampacity
Answer 4: all of these

Answer 1

Answer 3: ampacity

100 Ampacity

Question 2

A _____ consists of two or more ungrounded conductors that have a voltage between them and a neutral conductor that has equal voltage between it and each ungrounded conductor of the circuit and that is connected to the neutral conductor of the system.
Answer 1: multi-phase branch circuit
Answer 2: three-phase lighting supply circuit
Answer 3: poly-phase branch circuit
Answer 4: multiwire branch circuit

Answer 2

Answer 4: multiwire branch circuit

100 Branch Circuit, Multiwire (Multiwire Branch Circuit)

Question 3

A(An) _____ circuit breaker is a qualifying term indicating that there is a delay purposely introduced in the tripping action of the circuit breaker and the delay decreases as the magnitude of the current increases.
Answer 1: adverse time
Answer 2: inverse time
Answer 3: time delay
Answer 4: timed unit

Answer 3

Answer 2: inverse time

100 Circuit Breaker, Inverse Time (Inverse Time Circuit Breaker)

Question 4

A generator is a machine that converts mechanical energy into electrical energy by means of a _____ and alternator and/or inverter.
Answer 1: converter
Answer 2: rectifier
Answer 3: prime mover
Answer 4: turbine

Answer 4

Answer 3: prime mover

100 Generator (Generator Set)

Question 5

Article 210 provides the general requirements for _____ not over 1000V ac 1500V dc nominal.
Answer 1: outside branch circuits
Answer 2: branch circuits
Answer 3: ungrounded conductors
Answer 4: feeder calculations

Answer 5

Answer 2: branch circuits

210.1

Question 6

Where a branch circuit supplies continuous loads and/or noncontinuous loads the rating of the overcurrent device shall not be less than the noncontinuous load plus ____ of the continuous load.
Answer 1: 80 percent
Answer 2: 115 percent
Answer 3: 120 percent
Answer 4: 125 percent

Answer 6

Answer 4: 125 percent

210.20(A)

Question 7

Article _____ provides requirements for calculating branch-circuit feeder and service loads.
Answer 1: 200
Answer 2: 210
Answer 3: 220
Answer 4: 230

Answer 7

Answer 3: 220

220.1

Question 8

When calculations in Article 220 result in a fraction of an ampere that is less than _____ such fractions can be dropped.
Answer 1: 0.49
Answer 2: 0.5
Answer 3: 0.51
Answer 4: 0.8

Answer 8

Answer 2: 0.5

220.5(B)

Question 9

Outlets supplying luminaires shall be calculated based on the maximum _____ rating of the equipment.
Answer 1: power
Answer 2: true power
Answer 3: voltage
Answer 4: volt-ampere

Answer 9

Answer 4: volt-ampere

220.14(D)

Question 10

Sign and outline lighting outlets are to be calculated at a minimum of _____ for each required branch circuit specified in 600.5(A).
Answer 1: 1000 VA
Answer 2: 1200 VA
Answer 3: 1500 VA
Answer 4: 2000 VA

Answer 10

Answer 2: 1200 VA

220.14(F)

Question 11

If a motor or air-conditioning load is part of the noncoincident load and is not the largest of the noncoincident loads 125 percent of either the motor load or air-conditioning load whichever is _____ shall be used in the calculation.
Answer 1: less
Answer 2: smaller
Answer 3: larger
Answer 4: less or smaller

Answer 11

Answer 3: larger

220.60.

Question 12

If an energy management system (EMS) is used to limit the current to a feeder or service the set point value of the EMS shall be considered _____.
Answer 1: at 80 percent
Answer 2: at 90 percent
Answer 3: at 100 percent
Answer 4: a continuous load

Answer 12

Answer 4: a continuous load

220.70.

Question 13

Solid aluminum conductors of 8 AWG 10 AWG and 12 AWG shall be made of an AA-_____ series electrical grade aluminum alloy conductor material.
Answer 1: 1350
Answer 2: 2000
Answer 3: 6000
Answer 4: 8000

Answer 13

Answer 4: 8000

310.3(B)(1)

Question 14

Stranded aluminum conductors 8 AWG through 1000 kcmil marked as _____ shall be made of an AA-8000 series electrical grade aluminum alloy conductor material.
Answer 1: Type UF
Answer 2: Type NM
Answer 3: Type NMC
Answer 4: Type SE

Answer 14

Answer 4: Type SE

310.3(B)(2)

Question 15

The _____ core of a copper-clad aluminum conductor shall be made of an AA-8000 series electrical grade aluminum alloy conductor material.
Answer 1: aluminum
Answer 2: copper
Answer 3: steel
Answer 4: iron

Answer 15

Answer 1: aluminum

310.3(B)(3)

Question 16

Conductors in Article 310 shall be of copper aluminum or copper-clad aluminum unless otherwise specified. Copper-clad aluminum conductor material shall be _____.
Answer 1: identified for the use
Answer 2: listed
Answer 3: indicated as suitable
Answer 4: approved

Answer 16

Answer 2: listed

310.3(B)(4)

Question 17

Where installed in raceways conductors _____ and larger shall be stranded unless specifically permitted or required elsewhere in the NEC.
Answer 1: 10 AWG
Answer 2: 8 AWG
Answer 3: 6 AWG
Answer 4: 4 AWG

Answer 17

Answer 2: 8 AWG

310.3(C)

Question 18

Insulated conductors with the letters HH in their designation have a _____ insulation rating in a dry location.
Answer 1: 60°C
Answer 2: 75°C
Answer 3: 90°C
Answer 4: 110°C

Answer 18

Answer 3: 90°C

310.4(1) Table

Question 19

Insulated conductors with letter designation of _____ are permitted in a wet location with a maximum operating temperature of 90°C.
Answer 1: USE
Answer 2: RHW
Answer 3: XHWN
Answer 4: THWN-2

Answer 19

Answer 4: THWN-2

310.4(1) Table

Question 20

Where there are no adjustment or correction factors required the service conductors for a rated service of _____ supplying the entire load associated with an individual dwelling unit Table 310.12(A) shall be permitted to be applied.
Answer 1: 100A
Answer 2: 200A
Answer 3: 400A
Answer 4: all of these

Answer 20

Answer 4: all of these

310.12(A)

Question 21

Where there are no adjustment or correction factors required the feeder conductors rated between 100A and _____ supplying the entire load associated with an individual dwelling unit Table 310.12(A) shall be permitted to be applied..
Answer 1: 150A
Answer 2: 200A
Answer 3: 300A
Answer 4: 400A

Answer 21

Answer 4: 400A

310.12(B)

Question 22

No conductor shall be used where its _____ temperature exceeds that designated for the type of insulated conductor involved.
Answer 1: operating
Answer 2: ambient
Answer 3: highest
Answer 4: lowest

Answer 22

Answer 1: operating

310.14(A)(3)

Question 23

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.
Answer 1: ampacity
Answer 2: temperature
Answer 3: conductivity
Answer 4: short-circuit

Answer 23

Answer 2: temperature

310.14(A)(3) Informational Note 1

Question 24

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.
Answer 1: friction
Answer 2: magnetism
Answer 3: heat
Answer 4: compatibility

Answer 24

Answer 3: heat

310.14(A)(3) Informational Note 1(2)

Question 25

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 110.14(C). Answer 1: conductor Answer 2: feeder Answer 3: service Answer 4: termination

Answer 25

Answer 1: conductor | 310.15(A)

Question 26

Type _____ insulated conductors shall not be subject to ampacity adjustment where installed exposed to direct sunlight on a rooftop. Answer 1: THW-2 Answer 2: XHHW-2 Answer 3: THWN-2 Answer 4: RHW-2

Answer 26

Answer 2: XHHW-2 | 310.15(B)(2) Ex

Question 27

A raceway contains two three-phase 4-wire circuits where the neutrals carry only the unbalanced current from the other conductors. The ampacity adjustment factor for these conductors is _____. Answer 1: 70 percent Answer 2: 80 percent Answer 3: 90 percent Answer 4: 100 percent

Answer 27

Answer 2: 80 percent | 310.15(C)(1) Table

Question 28

Conductor adjustment factors shall not apply to conductors in raceways having a length not exceeding _____. Answer 1: 12 in. Answer 2: 24 in. Answer 3: 36 in. Answer 4: 48 in.

Answer 28

Answer 2: 24 in. | 310.15(C)(1)(b)

Question 29

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). Answer 1: neutral Answer 2: ungrounded Answer 3: grounding Answer 4: bonded

Answer 29

Answer 1: neutral | 310.15(E)(1)

Question 30

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. Answer 1: 240V Answer 2: 277V Answer 3: nonlinear Answer 4: linear

Answer 30

Answer 3: nonlinear | 310.15(E)(3)

Question 31

For the purposes of ampacity adjustment when determining the number of current-carrying conductors a grounding or bonding conductor _____ be counted when applying the provisions of 310.15(C)(1). Answer 1: shall not Answer 2: shall Answer 3: is permitted to Answer 4: can

Answer 31

Answer 1: shall not | 310.15(F)

Question 32

The ampacities specified in Table 310.16 apply to _____. Answer 1: conductors rated 60°C 75°C or 90°C Answer 2: wiring installed in an ambient temperature of 86°F Answer 3: where there is not more than three current-carrying conductors Answer 4: all of these

Answer 32

Answer 4: all of these | 310.16(2), (3), and (4)

Question 33

The minimum size THHN conductor for a 150A noncontinuous load is _____. Answer 1: 1 AWG Answer 2: 1/0 AWG Answer 3: 2/0 AWG Answer 4: 3/0 AWG

Answer 33

Answer 2: 1/0 AWG | 310.16 Table

Question 34

The minimum conductor size required for a 60A load if the terminals are rated 75°C is _____ THW copper. Answer 1: 2 AWG Answer 2: 4 AWG Answer 3: 6 AWG Answer 4: 8 AWG

Answer 34

Answer 3: 6 AWG | 310.16 Table

Question 35

The minimum size THW service-entrance conductors for a 200A commercial service is _____. Answer 1: 2/0 AWG Answer 2: 3/0 AWG Answer 3: 4/0 AWG Answer 4: 250 KCMIL

Answer 35

Answer 2: 3/0 AWG | 310.16 Table

Question 36

The conductor ampacity for 6 THW is _____. Answer 1: 55A Answer 2: 65A Answer 3: 70A Answer 4: 80A

Answer 36

Answer 2: 65A | 310.16 Table

Question 37

The 90°C rating shall be permitted to be used for ampacity adjustment and correction calculations for Type NM cable provided the final calculated ampacity does not exceed that of a _____ rated conductor. Answer 1: 60°C Answer 2: 75°C Answer 3: 90°C Answer 4: 104°C

Answer 37

Answer 1: 60°C | 334.80.

Question 38

For Types NM and NMC cable the _____ rating shall be permitted to be used for ampacity adjustment and correction calculations provided the final calculated ampacity does not exceed that of a 60°C rated conductor. Answer 1: 60°C Answer 2: 75°C Answer 3: 90°C Answer 4: 104°C

Answer 38

Answer 3: 90°C | 334.80.

Question 39

The ampacity adjustment factors in 310.15(C)(1) shall be applied to a metal wireway only where the number of current-carrying conductors in any cross section of the wireway exceeds _____. Answer 1: 30 Answer 2: 40 Answer 3: 50 Answer 4: 60

Answer 39

Answer 1: 30 | 376.22(B)

Question 40

Where insulated conductors are deflected within a metal wireway the wireway shall be sized to meet the bending requirements corresponding to _____ per terminal in Table 312.6(A). Answer 1: one wire Answer 2: two wires Answer 3: three wires Answer 4: four wires

Answer 40

Answer 1: one wire | 376.23(A)

Question 41

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. Answer 1: 15A Answer 2: 20A Answer 3: 25A Answer 4: 30A

Answer 41

Answer 2: 20A | 422.11(E)(2)

Question 42

If a branch circuit supplies a single nonmotor-operated appliance the rating of overcurrent protection shall not exceed _____ of the appliance rated current if the overcurrent protection rating is not marked and the appliance is rated over 13.30A. Answer 1: 100 percent Answer 2: 125 percent Answer 3: 150 percent Answer 4: 160 percent

Answer 42

Answer 3: 150 percent | 422.11(E)(3)

Question 43

The branch-circuit conductor(s) ampacity shall not be less than _____ of the load of the fixed electric space-heating equipment and any associated motor(s). Answer 1: 80 percent Answer 2: 110 percent Answer 3: 125 percent Answer 4: 150 percent

Answer 43

Answer 3: 125 percent | 424.4(B)

Question 44

Article _____ covers motors motor branch-circuit and feeder conductors and their protection motor overload protection motor control circuits motor controllers and motor control centers. Answer 1: 410 Answer 2: 430 Answer 3: 440 Answer 4: 450

Answer 44

Answer 2: 430 | 430.1

Question 45

For general motor applications the NEC table values for full load current values shall be used instead of the actual current rating marked on the motor nameplate when determining overload protection. Answer 1: TRUE Answer 2: FALSE

Answer 45

Answer 2: FALSE | 430.6(A)(1)

Question 46

For general motor applications separate motor overload protection shall be based on _____. Answer 1: NEC Tables 430.248 and 430.250 Answer 2: the manufacturer's instructions Answer 3: the motor disconnect current rating Answer 4: the motor nameplate current rating

Answer 46

Answer 4: the motor nameplate current rating | 430.6(A)(2)(1)
2023 UNEC1, Chapter 4

Question 47

Branch-circuit conductors supplying a single continuous-duty motor shall have an ampacity not less than _____ rating. Answer 1: 125 percent of the motor's nameplate current Answer 2: 125 percent of the motor's full-load current Answer 3: 125 percent of the motor's full locked-rotor Answer 4: 80 percent of the motor's full-load current

Answer 47

Answer 2: 125 percent of the motor's full-load current | 430.22

Question 48

Part IV of Article 430 specifies devices intended to protect _____ against overcurrent due to short circuits or ground faults. Answer 1: motor branch-circuit conductors Answer 2: motor control apparatus Answer 3: motors Answer 4: all of these

Answer 48

Answer 4: all of these | 430.51

Question 49

Short-circuit and ground-fault protection for a branch-circuit to which a motor or motor-operated appliance is connected shall be capable of carrying the ____ current of the motor. Answer 1: ampacity Answer 2: time delay Answer 3: thermal protection Answer 4: starting

Answer 49

Answer 4: starting | 430.52(B)

Question 50

The maximum dual-element time-delay fuse branch-circuit protection for a single-phase motor is _____ of the appropriate full-load current rating found in Table 430.248. Answer 1: 100 percent Answer 2: 115 percent Answer 3: 125 percent Answer 4: 175 percent

Answer 50

Answer 4: 175 percent | 430.52(C)(1) and Table 430.52(C)(1)

Question 51

The maximum rating or setting of an inverse time breaker used as the motor branch-circuit short-circuit and ground-fault protective device for a single-phase motor is _____ of the full-load current given in Table 430.248. Answer 1: 100 percent Answer 2: 115 percent Answer 3: 125 percent Answer 4: 250 percent

Answer 51

Answer 4: 250 percent | 430.52(C)(1) and Table 430.52(C)(1)

Question 52

Where the motor short-circuit and ground-fault protection devices determined by Table 430.52(C)(1) do not correspond to the standard sizes or ratings a _____ rating that does not exceed the next _____ standard ampere rating is permitted. Answer 1: higher Answer 2: lower Answer 3: smaller Answer 4: larger

Answer 52

Answer 1: higher | 430.52(C)(1)(a)

Question 53

The full-load current of a 115V 1 hp single-phase ac motor is _____. Answer 1: 12A Answer 2: 14A Answer 3: 16A Answer 4: 20A

Answer 53

Answer 3: 16A | 430.248 Table

Question 54

The full-load current of a 230V 1.50 hp single-phase ac motor is _____. Answer 1: 10A Answer 2: 12A Answer 3: 14A Answer 4: 16A

Answer 54

Answer 1: 10A | 430.248 Table

Question 55

The full-load current of a three-phase 208V 2 hp motor is _____. Answer 1: 7.50A Answer 2: 12A Answer 3: 14A Answer 4: 16A

Answer 55

Answer 1: 7.50A | 430.250 Table

Question 56

The full-load current of a three-phase 208V 7.50 hp motor is _____. Answer 1: 19A Answer 2: 22A Answer 3: 24.20A Answer 4: 38A

Answer 56

Answer 3: 24.20A | 430.250 Table

Question 57

The full-load current of a three-phase 230V 10 hp motor is _____. Answer 1: 19A Answer 2: 22A Answer 3: 28A Answer 4: 38A

Answer 57

Answer 3: 28A | 430.250 Table

Question 58

The full-load current of a three-phase 460V 15 hp motor is _____. Answer 1: 19A Answer 2: 21A Answer 3: 29A Answer 4: 42A

Answer 58

Answer 2: 21A | 430.250 Table

Question 59

Article 450 covers the installation of all _____. Answer 1: motors and motor control centers Answer 2: refrigeration and air-conditioning equipment Answer 3: transformers Answer 4: generators

Answer 59

Answer 3: transformers | 450.1

Question 60

The primary overcurrent protection for a transformer rated 1000V nominal or less with no secondary protection and having a primary current rating of _____ shall be set at not more than 125 percent or a higher rating that does not exceed the next higher standard rating shall be permitted. Answer 1: 9A or more Answer 2: less than 9A Answer 3: 2A or more Answer 4: less than 2A

Answer 60

Answer 1: 9A or more | 450.3(B) Table Note 1

Question 61

Article 625 covers the electrical conductors and equipment connecting an electric vehicle to premises wiring for the purposes of ____. Answer 1: charging Answer 2: power export Answer 3: bidirectional current flow Answer 4: any of these

Answer 61

Answer 4: any of these | 625.1

Question 62

Each outlet installed for the purpose of supplying EVSE (electric vehicle supply equipment) greater than _____ or 120V charging electric vehicles shall be supplied by an individual branch circuit. Answer 1: 12A Answer 2: 16A Answer 3: 18A Answer 4: 20A

Answer 62

Answer 2: 16A | 625.40.

Question 63

Overcurrent protection for circuits supplying electric vehicle supply (EVSE) and wireless power transfer (WPTE) equipment shall have a current rating of not less than _____ of the maximum load of the electric vehicle supply equipment. Answer 1: 100 percent Answer 2: 110 percent Answer 3: 125 percent Answer 4: 150 percent

Answer 63

Answer 3: 125 percent | 625.41

Question 64

Electric vehicle charging loads shall be considered to be a(an) _____ load. Answer 1: noncontinous Answer 2: hard Answer 3: extended Answer 4: continuous

Answer 64

Answer 4: continuous | 625.42