Understanding NEC Article 240

Question 1

The next higher standard rating overcurrent device above the ampacity of the ungrounded conductors being protected is permitted to be used provided the _____.
Answer 1: conductors being protected are not part of a branch circuit supplying more than one receptacle for cord-and-plug-connected portable loads
Answer 2: ampacity of the conductors does not correspond with the standard ampere rating of a fuse or circuit breaker
Answer 3: next higher standard rating does not exceed 800A
Answer 4: all of these

Answer 1

Answer 4: all of these

240.4(B)(1), (2), and (3)

Question 2

If the circuit’s overcurrent device exceeds _____ the conductor ampacity shall have a rating not less than the rating of the overcurrent device.
Answer 1: 800A
Answer 2: 1000A
Answer 3: 1200A
Answer 4: 2000A

Answer 2

Answer 1: 800A

240.4(C)

Question 3

Fixture wire is permitted to be tapped to the branch-circuit conductor in accordance with which of the following?
Answer 1: 15A or 20A circuits - 18 AWG up to 50 ft of run length
Answer 2: 15A or 20A circuits - 16 AWG up to 100 ft of run length
Answer 3: 20A circuits - 14 AWG and larger
Answer 4: all of these

Answer 3

Answer 4: all of these

240.5(B)(2)(1), (2), and (3)

Question 4

The standard ampere rating(s) for fuses is(are) _____.
Answer 1: 1A
Answer 2: 6A
Answer 3: 601A
Answer 4: all of these

Answer 4

Answer 4: all of these

240.6(A)

Question 5

Supplementary overcurrent protective devices are not permitted to be used _____.
Answer 1: to provide additional overcurrent protection for luminaires
Answer 2: to provide additional overcurrent protection for appliances
Answer 3: as the required branch-circuit overcurrent protective device
Answer 4: none of these

Answer 5

Answer 3: as the required branch-circuit overcurrent protective device

240.10

Question 6

Ground-fault protection of equipment shall be provided for solidly grounded wye electrical systems of more than 150 volts-to-ground but not exceeding 1000V phase-to-phase for each individual device used as a building or structure main disconnecting means rated _____ or more unless specifically exempted.
Answer 1: 1000A
Answer 2: 1500A
Answer 3: 2000A
Answer 4: 2500A

Answer 6

Answer 1: 1000A

240.13

Question 7

For multiwire branch circuits single-pole breakers with identified handle ties can be used to protect each _____ conductor for line-to-neutral connected loads.
Answer 1: ungrounded
Answer 2: grounded
Answer 3: grounding
Answer 4: neutral

Answer 7

Answer 1: ungrounded

240.15(B)(1)

Question 8

Feeder taps are permitted to be located at any point on the _____ side of the feeder overcurrent protective device.
Answer 1: load
Answer 2: line
Answer 3: supply
Answer 4: end

Answer 8

Answer 1: load

240.21(B)

Question 9

Tap conductors not over 25 ft in length are permitted providing the _____.
Answer 1: ampacity of the tap conductors is not less than one-third the rating of the overcurrent device protecting the feeder conductors being tapped
Answer 2: tap conductors terminate in a single circuit breaker or set of fuses that limits the load to the ampacity of the tap conductors
Answer 3: tap conductors are suitably protected from physical damage
Answer 4: all of these

Answer 9

Answer 4: all of these

240.21(B)(2)(1), (2), (3)

Question 10

The next size up rule in 240.4(B) is not permitted for _____ secondary conductors.
Answer 1: transformer
Answer 2: generator
Answer 3: motor
Answer 4: relay

Answer 10

Answer 1: transformer

240.21(C)

Question 11

Secondary conductors not over 10 ft long shall be enclosed in a(an) _____.
Answer 1: cable
Answer 2: enclosure
Answer 3: raceway
Answer 4: all of these

Answer 11

Answer 3: raceway

240.21(c)(2)(3)

Question 12

Outside secondary conductors can be of unlimited length without overcurrent protection at the point they receive their supply if the _____.
Answer 1: conductors are protected from physical damage
Answer 2: conductors terminate at a single overcurrent device equal to or less than their ampacity
Answer 3: overcurrent device is part of the building disconnect
Answer 4: all of these

Answer 12

Answer 4: all of these

240.21(C)(4)(1), (2), and (3)

Question 13

Circuit breakers and switches containing fuses shall be readily accessible and installed so the center of the grip of the operating handle of the switch or circuit breaker when in its highest position is not more than _____ above the floor or working platform.
Answer 1: 6 ft 4 in.
Answer 2: 6 ft 5 in.
Answer 3: 6 ft 6 in.
Answer 4: 6 ft 7 in.

Answer 13

Answer 4: 6 ft 7 in.

240.24(A)

Question 14

Overcurrent protective devices shall not be located _____.
Answer 1: where exposed to physical damage
Answer 2: near easily ignitible materials such as in clothes closets
Answer 3: in bathrooms showering facilities or locker rooms with showering facilities
Answer 4: all of these

Answer 14

Answer 4: all of these

240.24(C), (D) and E

Question 15

_____ shall not be located over the steps of a stairway.
Answer 1: Disconnect switches
Answer 2: Overcurrent protective devices
Answer 3: Knife switches
Answer 4: Transformers

Answer 15

Answer 2: Overcurrent protective devices

240.24(F)

Question 16

Circuit breaker enclosures shall be permitted to be installed _____ where the circuit breaker is installed in accordance with 240.81
Answer 1: vertically
Answer 2: horizontally
Answer 3: face up
Answer 4: face down

Answer 16

Answer 2: horizontally

240.33

Question 17

Where the circuit breaker handles are operated vertically the up position of the handle shall be the _____ position.
Answer 1: on
Answer 2: off
Answer 3: tripped
Answer 4: any of these

Answer 17

Answer 1: on

240.81

Question 18

Circuit breakers used to switch high-intensity discharge lighting circuits shall be listed and marked as _____.
Answer 1: SWD
Answer 2: HID
Answer 3: SWD or HID
Answer 4: SWD and HID

Answer 18

Answer 2: HID

240.83(D)

Question 19

A circuit breaker with a _____ rating such as 120/240V or 277/480V can be used on a solidly grounded circuit where the nominal voltage of any conductor to ground does not exceed the lower of the two values and the nominal voltage between any two conductors does not exceed the higher value.
Answer 1: straight
Answer 2: slash
Answer 3: high
Answer 4: low

Answer 19

Answer 2: slash

240.85

Question 20

A circuit breaker with a slash rating such as 120/240V or 480Y/277V shall be permitted to be applied in a solidly grounded circuit where the nominal voltage of any conductor to ground _____ the lower of the two values of the circuit breakers voltage rating and the nominal voltage between any two conductors does not exceed the higher value of the circuit breaker’s voltage rating.
Answer 1: is equal to
Answer 2: is equal to or greater than
Answer 3: does not exceed
Answer 4: is equal to 125 percent of

Answer 20

Answer 3: does not exceed

240.85