NCCER 26305 CERTIFICATION
EVALUATION EXAMS SET COMPLETE
SOLUTIONS VERIFIED ACCURACY
ALREADY PASSED
⩥ NEC ? covers the requirements for the motor controller disconnecting
means.
Answer: 430.102(A)
⩥ The type of motor disconnecting means is covered by NEC ? .
Answer: 430.109
⩥ A horsepower-rated switch or circuit breaker is permitted as both the
motor controller and disconnecting means in accordance with NEC ? .
Answer: 430.111
⩥ The requirements for motor-circuit overcurrent protection for motors
over 1,000 volts are covered in what section of Article 430?
Answer: 430.225
⩥ Determine the branch-circuit conductor size (copper, THW) needed
for a 3-phase, 75-horsepower, 240-volt squirrel cage motor with a
nameplate current of 188 amperes, a temperature rise of 40°C, and a
,marked service factor of 1.15 when starting current is not a problem. The
terminals are rated 75°C.
Answer: Table 430.250 shows full-load current to be 192 amperes for
the 75-horsepower motor.
Conductor ampacity = Table amperes × 125%
= 192 × 1.25
= 240 A
Table 310.16 requires 250 kcmil conductors
⩥ Determine the maximum rating of time-delay fuses needed for a 3-
phase, 75-horsepower, 240-volt squirrel cage motor with a nameplate
current of 188 amperes, a temperature rise of 40°C, and a marked
service factor of 1.15 when starting current is not a problem. Assume the
motor will start with this selection.
Answer: Table 430.250 shows full-load current to be 192 amperes for
the 75-horsepower motor.
Max. time-delay fuse size = Table amperes × 175%
= 192 × 1.75
= 336 A
430.52(C)(1) Ex. No. 1 allows the next higher standard rating.
Max. Fuse size = 350 A
⩥ Determine the maximum overload protection trip or rating for a 3-
phase, 75-horsepower, 240-volt squirrel cage motor with a nameplate
, current of 188 amperes, a temperature rise of 40°C, and a marked
service factor of 1.15 when starting current is not a problem.
Answer: Max. overload protection for marked service factor of 1.15 or
marked temperature rise of 40°C is 125% of the nameplate rating per
430.32(A)(1).
Overload protection = 188 × 1.25
= 235 A
⩥ Which NEC article applies to electric motor-driven air-conditioning
and refrigerating equipment and to the branch circuits and controllers for
such equipment?
Answer: 440
⩥ The motor-compressor branch-circuit short-circuit and ground-fault
protective device shall be capable of carrying the starting current of the
motor. A protective device having a rating or setting not exceeding 175%
of the motor-compressor rated load current or branch-circuit selection
current, whichever is greater, shall be permitted, provided that where the
protection specified is not sufficient for the starting current of the motor,
the rating or setting shall be permitted to be increased, but shall not
exceed ? of the motor rated load current or branch-circuit selection
current, whichever is greater.
Answer: 225%
440.22(A)
EVALUATION EXAMS SET COMPLETE
SOLUTIONS VERIFIED ACCURACY
ALREADY PASSED
⩥ NEC ? covers the requirements for the motor controller disconnecting
means.
Answer: 430.102(A)
⩥ The type of motor disconnecting means is covered by NEC ? .
Answer: 430.109
⩥ A horsepower-rated switch or circuit breaker is permitted as both the
motor controller and disconnecting means in accordance with NEC ? .
Answer: 430.111
⩥ The requirements for motor-circuit overcurrent protection for motors
over 1,000 volts are covered in what section of Article 430?
Answer: 430.225
⩥ Determine the branch-circuit conductor size (copper, THW) needed
for a 3-phase, 75-horsepower, 240-volt squirrel cage motor with a
nameplate current of 188 amperes, a temperature rise of 40°C, and a
,marked service factor of 1.15 when starting current is not a problem. The
terminals are rated 75°C.
Answer: Table 430.250 shows full-load current to be 192 amperes for
the 75-horsepower motor.
Conductor ampacity = Table amperes × 125%
= 192 × 1.25
= 240 A
Table 310.16 requires 250 kcmil conductors
⩥ Determine the maximum rating of time-delay fuses needed for a 3-
phase, 75-horsepower, 240-volt squirrel cage motor with a nameplate
current of 188 amperes, a temperature rise of 40°C, and a marked
service factor of 1.15 when starting current is not a problem. Assume the
motor will start with this selection.
Answer: Table 430.250 shows full-load current to be 192 amperes for
the 75-horsepower motor.
Max. time-delay fuse size = Table amperes × 175%
= 192 × 1.75
= 336 A
430.52(C)(1) Ex. No. 1 allows the next higher standard rating.
Max. Fuse size = 350 A
⩥ Determine the maximum overload protection trip or rating for a 3-
phase, 75-horsepower, 240-volt squirrel cage motor with a nameplate
, current of 188 amperes, a temperature rise of 40°C, and a marked
service factor of 1.15 when starting current is not a problem.
Answer: Max. overload protection for marked service factor of 1.15 or
marked temperature rise of 40°C is 125% of the nameplate rating per
430.32(A)(1).
Overload protection = 188 × 1.25
= 235 A
⩥ Which NEC article applies to electric motor-driven air-conditioning
and refrigerating equipment and to the branch circuits and controllers for
such equipment?
Answer: 440
⩥ The motor-compressor branch-circuit short-circuit and ground-fault
protective device shall be capable of carrying the starting current of the
motor. A protective device having a rating or setting not exceeding 175%
of the motor-compressor rated load current or branch-circuit selection
current, whichever is greater, shall be permitted, provided that where the
protection specified is not sufficient for the starting current of the motor,
the rating or setting shall be permitted to be increased, but shall not
exceed ? of the motor rated load current or branch-circuit selection
current, whichever is greater.
Answer: 225%
440.22(A)
