Deck 6: Determining Branch Circuit, Feeder Circuit, and Service Entrance Requirements

Question 1

The rating of a panelboard is based on the ampacity of the __________.

A) main breaker
B) bus bar
C) service conductor
D) total amperage of each breaker in the panelboard

Answer 1

B

Question 2

The circuit conductors between the service equipment and the final branch circuit overcurrent protection device is a(n) __________.

A) open circuit
B) branch circuit
C) feeder circuit
D) service conductor

Answer 2

C

Question 3

Section 210.11(C)(4) requires at least one 120-volt, 20-ampere garage branch circuit to supply light fixtures in each attached garage and each detached garage that has electrical power.

Answer 3

False
The branch circuit is required to supply receptacles.

Question 4

An individual branch circuit supplies only one piece of electrical equipment such as an electric range or a dishwasher.

Question 5

An area including a basin with one or more of the following: a toilet, a urinal, a tub, a shower, a bidet, or similar plumbing fixtures is called a bathroom according to the NEC.

Question 6

When doing a standard service entrance calculation, if a residence has four fixed appliances, a demand factor of __________% is applied to the total load of these appliances.

A) 50
B) 75
C) 80
D) 100

Question 7

A circuit that consists of two or more ungrounded conductors that have a voltage between them, and a grounded conductor that has equal voltage between it and each ungrounded conductor of the circuit is called a multiwire circuit.

Question 8

According to the NEC, the unit load used to calculate the minimum number of general lighting branch circuits in a dwelling is __________ volt-amperes per square foot.

A) 2
B) 3
C) 4
D) 5

Question 9

Which of the following areas is included when computing the general lighting load of a house?

A) Open porches
B) Garages
C) Crawl spaces
D) Finished basements

Question 10

Kitchen lighting outlets are permitted to be connected to any of the small-appliance branch circuits that provide power for the kitchen receptacles.

Question 11

In residential wiring, which of the following house areas does not have its power supplied by a small appliance circuit?

A) Bathroom
B) Dining room
C) Kitchen
D) Pantry

Question 12

The NEC defines a branch circuit as the circuit conductors between the service equipment and the power or lighting outlets.

Question 13

If cables are bundled together for more than 24 inches and the total number of current-carrying conductors exceeds __________, the ampacity of the conductors must be derated.

A) two
B) three
C) four
D) five

Question 14

When doing service entrance calculations, 1 volt-ampere equals __________.

A) 1 joule
B) 1 watt
C) 1 ohm
D) 1 mil

Question 15

The point on the wiring system at which current is taken to supply electrical equipment is called a receptacle.

Question 16

A(n) __________ is the circuit conductors between the final overcurrent device and the outlets.

A) open circuit
B) branch circuit
C) feeder circuit
D) service conductor

Question 17

A house with 2000 square feet of habitable living space will require at least _________ general lighting circuits if 15-ampere circuit breakers are used to provide circuit protection.

A) 3
B) 4
C) 5
D) 6

Question 18

Section 230.79(C) requires that for a single-family dwelling, the service disconnecting means must have a rating of not less than 100 amperes.

Question 19

When doing a standard service entrance calculation and applying the demand factor to the total load of the general lighting load, the small appliance circuits, and the laundry circuit, the first ___________ volt-amperes are computed at 100%.

A) 2000
B) 2500
C) 3000
D) 4000

Question 20

Which of the following is not permitted to be connected to a small appliance branch circuit?

A) Refrigerator
B) Electric clock
C) Gas stove
D) Kitchen lighting fixture

Question 21

According to Table 310.15(B)(16) in the NEC, the ampacity for a 3 AWG copper conductor using the 75 degree Celsius column is ____________.

A) 85 amperes
B) 95 amperes
C) 100 amperes
D) 200 amperes

Question 22

A household electric range has a rating of 11 kW.When computing the service load using the standard calculation, a minimum of ____________________ watts will be used.

Question 23

According to Table 310.15(B)(16) in the NEC, the ampacity for a 12 AWG copper conductor using the 60 degree Celsius column is ____________.

A) 20 amperes
B) 25 amperes
C) 30 amperes
D) 40 amperes

Question 24

The NEC requires at least ____________________ small-appliance circuits be installed in each dwelling unit.

Question 25

When cables or conductors are physically tied, wrapped, or taped together, they are considered to be ______________.

A) bundled
B) messy
C) supported
D) secured

Question 26

The temperature of the air that surrounds an object on all sides is called ________ temperature.

Question 27

The current in amperes that a conductor can carry continuously under certain conditions of use without exceeding its temperature rating is called __________.

Question 28

The minimum service entrance disconnecting means rating for a single-family home permitted by the NEC is __________ amperes.

A) 60
B) 75
C) 100
D) 200

Question 29

Which of the following loads does not require a grounded circuit conductor?

A) Two wires, 120 volt
B) Three wires, 120/240 volt
C) Two wires, 240 volt
D) None of the above

Question 30

The NEC states that each two-wire small-appliance circuit shall be computed at ____________________ volt-amperes.

Question 31

If an electric clothes dryer has a nameplate rating of 4500 watts, ____________________ watts will be used in the standard method for service calculation.

Question 32

All of the following types of branch circuits are found in residential wiring except:

A) general lighting
B) laundry
C) large appliance
D) small appliance

Question 33

According to Section 310.15(B)(7) in the NEC, the minimum conductor size for a 300-ampere residential service entrance is _________ Cu or _________ Al.

A) 2 AWG; 1/0 AWG
B) 2/0 AWG; 4/0 AWG
C) 250 kcmil; 350 kcmil
D) 400 kcmil; 600 kcmil

Question 34

A 1900 square foot residence has a general lighting load of ____________________ volt-amperes.

Question 35

According to Section 310.15(B)(7)(1), for one-family dwelling service entrance ratings of 100 through 400 amperes the service conductors can have a rating of _____ percent of the service rating.

A) 73
B) 83
C) 100
D) 125

Question 36

For the types of branch circuits found in residential wiring, the fuse or circuit breaker size can never be larger than ____________________ amperes for a 12 AWG copper conductor.

Question 37

The NEC states that the load for a household electric clothes dryer must be computed at ____________________ watts or the nameplate rating, whichever is greater.

Question 38

A 200-ampere-rated panel is designed and manufactured to accommodate __________ circuits.

A) 30
B) 40
C) 42
D) Any of the above

Question 39

According to Section 310.15(B)(7) in the NEC, the minimum conductor size for a 200-ampere residential service entrance is _________ Cu or _________ Al.

A) 4 AWG; 2 AWG
B) 3 AWG; 1 AWG
C) 2 AWG; 1/0 AWG
D) 2/0 AWG; 4/0 AWG

Question 40

Another way to calculate the minimum number of general lighting circuits required in a dwelling unit is to divide the total habitable square foot living area by ____________ square feet for 15-ampere branch circuits and ______________ square feet for 20-ampere branch circuits.

A) 200/300
B) 600/800
C) 750/1000
D) 1500/2000

Question 41

When are subpanels used in residential wiring?

Question 42

If the total computed load of a residence is 45,840 volt-amperes, the computed amperage of the residence is ____________________ amperes.

Question 43

How are the electric heating and the air conditioning loads computed when calculating the total electrical load for a residential service?

Question 44

A house will have an electric range that has a nameplate rating of 14 kW.What is the load used to calculate the branch circuit rating?

Question 45

A house will have a counter-mounted cooking unit with a nameplate rating of 4 kW and a wall-mounted oven with a nameplate rating of 6 kW.A separate individual branch circuit will be run to the counter-mounted cooking unit and to the wall-mounted oven.What is the branch circuit load for each of the appliances in amperes?

Question 46

When is bathroom lighting permitted to be connected to the 20-ampere-rated bathroom branch circuit?

Question 47

Section 210.4 covers multiwire branch circuits and states that each multiwire branch circuit must have a way to simultaneously disconnect both ungrounded "hot" conductors at the point where the circuit originates.What does this mean as far as the type of circuit breaker that would have to be used?

Question 48

Dividing the total computed load in volt-amperes by the residential service voltage of ____________________ volts will give the minimum ampacity that the service conductors must be rated for.

Question 49

A house will have a countertop cook unit rated at 5 kW and a built-in oven rated at 7 kW.Both will be connected to the same branch circuit and be located in the same room.What is the load used to calculate the branch circuit rating?