Master Electrician Exam Sample Questions to Practice
Master electrician exams lean harder on load calculations and service sizing than journeyman exams do, since the license is what lets you pull permits and sign off on system design. Below are eight original practice questions built around the calculation types that show up most often, each with a worked answer and the NEC section it comes from.
These are original practice problems, not reproductions of any state’s actual exam bank. Table values referenced here reflect NEC 2023-cycle standard methodology; confirm current table numbers against whichever code edition your state has adopted before test day, since adoption dates vary by state.
Question 1: General lighting demand load
A single-family dwelling has 2,000 square feet of living space. Using the standard method, what’s the demand load for general lighting, small appliance, and laundry circuits combined?
Worked answer: General lighting at 3 VA per square foot (NEC 220.41) = 6,000 VA. Two small-appliance circuits at 1,500 VA each (220.52(A)) = 3,000 VA. One laundry circuit at 1,500 VA (220.52(B)) = 1,500 VA. Total connected load = 10,500 VA. Applying Table 220.42’s general demand factors (first 3,000 VA at 100 percent, the remainder up to 120,000 VA at 35 percent): 3,000 + (7,500 x 0.35) = 3,000 + 2,625 = 5,625 VA demand load.
Question 2: Range demand load
A dwelling has one 12 kW electric range. What demand load does the standard method assign it?
Worked answer: Table 220.55, Column C, assigns a single range not exceeding 12 kW a demand load of 8 kW (8,000 VA), regardless of the nameplate rating, as long as it doesn’t exceed the 12 kW threshold.
Question 3: Dryer demand load
A dwelling has one electric dryer with a 4.5 kW nameplate rating. What demand load applies?
Worked answer: NEC 220.54 requires using the greater of the nameplate rating or 5 kVA (5,000 VA) per dryer. Since 5,000 VA exceeds the 4.5 kW nameplate, the demand load is 5,000 VA.
Question 4: Grounding electrode conductor sizing
A service uses 2/0 AWG copper ungrounded conductors. Using Table 250.66, what’s the minimum grounding electrode conductor size?
Worked answer: Table 250.66 sizes the grounding electrode conductor off the largest ungrounded service conductor. For service conductors in the 1/0 through 3/0 AWG copper range, the table requires a minimum 4 AWG copper grounding electrode conductor.
Question 5: Motor branch-circuit conductor sizing
A continuous-duty motor has a full-load current (FLC) of 28 amps per the NEC ampacity tables. What’s the minimum branch-circuit conductor ampacity required?
Worked answer: NEC 430.22 requires branch-circuit conductors for a single continuous-duty motor to have an ampacity of at least 125 percent of the motor’s FLC. 28 x 1.25 = 35 amps minimum conductor ampacity.
Question 6: Optional method general loads
Using the optional method (220.82) for a dwelling with 10,500 VA of general loads (lighting, small appliance, laundry combined) and no other loads yet applied, what’s the demand load?
Worked answer: The optional method applies 100 percent to the first 10 kVA (10,000 VA) and 40 percent to the remainder. 10,000 + ((10,500 - 10,000) x 0.40) = 10,000 + 200 = 10,200 VA, before adding fixed appliances, heating, and air conditioning loads.
Question 7: Service disconnect count
A commercial service has ungrounded conductors feeding six separate disconnecting means grouped at one location, each individually sized for a portion of the total load. Does this comply with NEC 230.71?
Worked answer: Yes. NEC 230.71(A) permits up to six disconnecting means for a service, grouped in one location, without requiring them to be combined into a single main disconnect, subject to the exceptions listed in that section.
Question 8: Working clearance
A 480Y/277V panelboard is installed against a wall with no live parts on the opposite side. Per NEC Table 110.26(A)(1), what minimum working clearance is required under Condition 1?
Worked answer: For systems over 150 volts to ground (480Y/277V has a 277V line-to-ground voltage) under Condition 1, Table 110.26(A)(1) requires a minimum of 3 feet. Condition 2 and Condition 3 installations for the same voltage range require 3 feet 6 inches and 4 feet respectively.
Snippet reference: demand factor quick table
| Calculation | NEC section | Key number |
|---|---|---|
| General lighting, dwelling | 220.41 | 3 VA/sq ft |
| Small appliance circuit, each | 220.52(A) | 1,500 VA |
| Laundry circuit | 220.52(B) | 1,500 VA |
| Standard method general demand | 220.42 | 100% first 3,000 VA, 35% remainder to 120,000 VA |
| Optional method, dwelling | 220.82 | 100% first 10 kVA, 40% remainder |
| Motor branch-circuit conductor | 430.22 | 125% of FLC |
Do master exams test business and law topics, or just NEC calculations?
It depends on the state issuing the license. Some states test master candidates on code and calculations only; others, particularly where the master license also unlocks contracting authority, add a separate business and law exam module. California’s C-10 contractor path, for example, requires both a trade exam and a separate law and business exam, each scored independently, per the Contractors State License Board. Check your state board’s current candidate handbook to see which modules apply.
FAQ
Are these real questions from a state master electrician exam? No. These are original practice problems built around the NEC calculation types that commonly appear on master-level exams. No state’s actual exam bank is reproduced here, since most states treat their live question banks as confidential.
What NEC edition should I study these calculations against? Whichever edition your state has currently adopted for testing, which may lag the newest published NEC by a code cycle or more. Table numbers and demand factors referenced here reflect standard NEC 2023-cycle methodology; verify against your state’s current handbook before exam day.
Is the optional method or standard method used more often on master exams? Both appear. The standard method is more common in the exam room since it tests whether you understand each demand factor individually; the optional method shows up as a faster alternative for straightforward single-family dwelling calculations.
How many calculation questions typically appear on a master electrician exam? It varies by state and testing vendor, and most boards don’t publish an exact breakdown. Load, service, and conductor sizing problems make up a meaningful minority of most state exams, with the remainder split between code recall and safety topics. Check your state’s candidate handbook for any published content outline.