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The NASCLA-EC exam has 110 questions and runs 4 hours 30 minutes.
These 10 free NASCLA-EC questions are organized by exam domain, so you can see how each part of the NASCLA Accredited Trade Examination for Electrical Contractors (Master Electricians/Unlimited Electricians) blueprint is tested. Reveal the answer and explanation under each question.
An electrical contractor estimates $48,000 in direct labor, materials, and equipment for a tenant improvement. An additional $6,000 of company overhead must be recovered through this job. The company owner wants the amount remaining after both costs to equal 25% of the selling price. With no taxes or other charges to add, which quotation meets that target?
Correct answer: D - $72,000
During lockout/tagout of a 480 V motor circuit, an electrician checks a properly rated meter on a known energized source, then measures zero volts for every required phase-to-phase and phase-to-ground combination at the work location. On the required post-test check, the meter reads zero on the known energized source. Under NFPA 70E, 2024 edition, what must happen before the conductors can be treated as de-energized?
Correct answer: A - Repeat the complete absence-of-voltage verification with functioning, adequately rated test equipment.
Two unequal 120 V loads share a neutral on a 120/240 V, single-phase multiwire branch circuit. At the load junction, a qualified electrician records 82 V from L1 to neutral, 158 V from L2 to neutral, and 240 V from L1 to L2. Each line measures 120 V to the equipment grounding conductor. The circuit is then isolated. Which fault best explains this pattern?
Correct answer: B - The shared neutral is open or has a high-resistance connection.
The fault-current study for a new 480 V industrial control panel shows 22 kA available at its supply terminals. The panel is marked with a 10 kA short-circuit current rating (SCCR), while its main breaker has a 65 kA interrupting rating at 480 V. No listed or evaluated combination establishes a higher assembly rating. What conclusion follows under the 2023 NEC?
Correct answer: B - The panel SCCR is inadequate even though the main breaker has sufficient interrupting capacity.
A 120 V, single-phase, two-wire feeder supplies 32 A of office lighting for ten hours each workday and 17 A of fixed, nonmotor test equipment for no more than 30 minutes at a time. Both loads can operate simultaneously. The breaker assembly is not listed for 100% continuous loading, and conductor selection will accommodate the required breaker. Under the 2023 NEC, what is the smallest standard feeder circuit-breaker rating for these loads?
Correct answer: C - 60 A
A buried PVC raceway connects two indoor electrical rooms. Before pulling conductors, the foreman confirms that the raceway is dry and proposes using copper wire marked only THHN; neither the conductor markings nor its certification identify a wet-location rating. The project uses the 2023 NEC. How should the conductor selection be resolved?
Correct answer: C - Specify a wet-location conductor, such as THWN-2, for the underground raceway.
A device box receives two 12/2 cables and one 12/3 cable, each with a 12 AWG equipment grounding conductor. All seven insulated conductors are spliced or terminated in the box. It also contains one duplex receptacle on a single yoke, one internal cable clamp, and three 12 AWG pigtails that remain entirely inside the box. There are no other fittings or devices. Using the 2023 NEC allowance of 2.25 cubic inches per 12 AWG conductor volume, how much box volume must the design provide?
Correct answer: B - 24.75 cubic inches
A reviewer flags a 45 A circuit breaker supplying an air-conditioning condensing unit through 10 AWG copper conductors. The unit is marked "Minimum Circuit Ampacity: 27 A" and "Maximum Fuse or Circuit Breaker: 45 A." The conductors have a final allowable ampacity of 30 A after all applicable checks. The installation follows the equipment instructions and satisfies the remaining requirements of the 2023 NEC. Is a change required solely because the breaker rating exceeds the conductor ampacity?
Correct answer: A - No; the conductor and breaker satisfy the equipment-specific minimum and maximum ratings.
A continuous-duty three-phase motor has a 12 A nameplate current, a 1.0 service factor, and a marked temperature rise of 35°C. Its applicable NEC table full-load current is 14 A. Separate overload protection is being specified, and no increase for starting or carrying the load is needed. Under the 2023 NEC, which current basis and percentage govern the ordinary maximum overload-trip current?
Correct answer: D - Motor nameplate current; 125%.
A solvent-transfer area can contain ignitable concentrations of flammable vapor during normal operation. The hazardous-area documentation identifies the vapor as Group D with an ignition temperature of 170°C. Four otherwise suitable devices have the markings below. For the Class/Division system in the 2023 NEC, which device satisfies both the location classification and the temperature requirement?
Correct answer: D - Class I, Division 1, Group D; T4, maximum surface temperature 135°C.
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