TheoryMaster Electrician 2
Practice Test
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30 free Master Electrician 2 questions
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Code Administration & Safety
The NEC is organized into chapters. Which chapter covers wiring methods and materials?
Correct — A. NEC Chapter 3 covers Wiring Methods and Materials (Articles 300–392). Chapter 1 covers General Requirements, Chapter 5 covers Special Occupancies, and Chapter 7 covers Special Conditions. -
Code Administration & Safety
NEC Article 100 is primarily dedicated to which of the following?
Correct — C. Article 100 contains definitions of terms used throughout the NEC. Understanding these definitions is essential because they govern how other code requirements are applied. -
Code Administration & Safety
The NEC defines the Authority Having Jurisdiction (AHJ) as the organization, office, or individual responsible for what?
Correct — B. The AHJ is the entity empowered to enforce the NEC — typically the local building or electrical inspector. They interpret requirements and can approve or reject installations. -
Code Administration & Safety
Under NEC 90.4, if equipment or materials are not covered by the NEC, who is authorized to allow their use?
Correct — D. NEC 90.4 gives the AHJ authority to approve equipment or installations not specifically addressed by the Code, provided the installation is judged to be safe. -
Code Administration & Safety
What is the primary purpose of the NEC as stated in Article 90?
Correct — A. NEC 90.1 states the purpose is the practical safeguarding of persons and property. The Code is not a design specification or instruction manual, but a safety document. -
Code Administration & Safety
Which of the following installations is specifically NOT covered by the NEC?
Correct — C. NEC 90.2(B) lists several installations outside the Code's scope, including ships, watercraft, railway rolling stock, and aircraft, which are governed by separate standards. -
Code Administration & Safety
When the NEC requires that equipment be 'listed,' it means the equipment has been:
Correct — B. Listed equipment has been examined by an NRTL (such as UL or ETL) and found to meet applicable product standards. The NEC strongly prefers listed equipment because it provides a documented baseline of safety. -
Code Administration & Safety
According to NEC 110.3(B), after listed or labeled equipment is installed, it must be used:
Correct — D. NEC 110.3(B) requires that listed and labeled equipment be installed and used in accordance with the instructions included in the listing or labeling. Deviating from those instructions violates the Code. -
Code Administration & Safety
Before beginning most electrical installations, a master electrician typically must obtain:
Correct — A. Most jurisdictions require an electrical permit (issued by the AHJ) before work begins. The permit triggers the inspection process that ensures code compliance. -
Code Administration & Safety
NEC 90.4 grants authority to whom to interpret the NEC requirements and approve equipment or wiring that is not specifically covered by the Code?
Correct — C. NEC 90.4 vests interpretive authority and the power to approve unlisted equipment or alternative methods in the Authority Having Jurisdiction. The AHJ may grant 'special permission' (written consent) for installations not specifically covered by the Code. -
Code Administration & Safety
In NEC text, the word 'shall' indicates:
Correct — B. Per NEC 90.5, 'shall' denotes a mandatory requirement. 'Shall not' is a mandatory prohibition. 'Should' indicates a recommendation, and 'shall be permitted' indicates a permissive rule. -
Code Administration & Safety
The phrase 'shall be permitted' in NEC text signifies:
Correct — D. NEC 90.5(B) defines 'shall be permitted' as identifying options or alternative methods. It is not a mandate but a statement that the Code allows the described practice. -
Code Administration & Safety
OSHA's general-industry electrical standard is contained primarily in which part of 29 CFR 1910?
Correct — A. OSHA 29 CFR 1910 Subpart S covers electrical safety in general industry workplaces. It addresses design safety standards and safety-related work practices. -
Code Administration & Safety
OSHA 29 CFR 1910.333 establishes the lockout/tagout requirements for energized electrical equipment. Which of the following is NOT a required element of a proper lockout procedure under this standard?
Correct — C. OSHA 1910.333 and the broader LOTO standard (1910.147) require notifying employees, shutting down equipment, and releasing stored energy — but the energy-isolating device (lockout lock) must remain in place until work is complete, not be permanently removed. -
Code Administration & Safety
Under OSHA's LOTO standard (29 CFR 1910.147), when may a tagout device be used in place of a lockout device?
Correct — B. OSHA 1910.147(c)(3) allows tagout only when the energy-isolating device cannot physically accommodate a lock. Otherwise, lockout is required because tags alone can be removed or ignored. -
Code Administration & Safety
A master electrician is performing maintenance on a 480 V three-phase panel. After locking out and tagging out, the next step per OSHA LOTO protocol before touching conductors is:
Correct — D. After LOTO is applied, OSHA requires verification that the equipment is de-energized — typically by attempting to start the equipment and/or using a calibrated test instrument. 'Try-before-touch' prevents contact with unexpectedly live conductors. -
Code Administration & Safety
NFPA 70E establishes the requirement for an arc-flash risk assessment before workers approach energized equipment. Who is responsible for determining the arc-flash boundary and incident energy level?
Correct — A. NFPA 70E 130.5 requires the employer to ensure an arc-flash risk assessment is performed by a qualified person. The assessment determines incident energy and the required PPE category. -
Code Administration & Safety
According to NFPA 70E, what is the Restricted Approach Boundary for unqualified workers around exposed energized conductors at 480 V phase-to-phase?
Correct — C. NFPA 70E 130.4 establishes the Restricted Approach Boundary. Unqualified workers cannot enter this boundary unless continuously escorted and protected by a qualified person. All voltages above 50 V require boundary assessment. -
Code Administration & Safety
Per NFPA 70E Table 130.5(C), which PPE category is typically required when working inside the arc-flash boundary of a 480 V switchboard with doors open and bolted bus exposed, with incident energy estimated at 8 cal/cm²?
Correct — B. NFPA 70E PPE Category 2 requires arc-rated clothing and equipment with a minimum 8 cal/cm² arc rating. An estimated 8 cal/cm² incident energy falls within the Category 2 threshold. -
Code Administration & Safety
NEC 110.26 requires minimum working space depth in front of electrical panels operating at 120/240 V (Condition 1). What is that minimum depth?
Correct — D. NEC Table 110.26(A)(1) requires a minimum of 36 inches of working space depth (front to back) for equipment operating up to 150 V to ground under Condition 1. This space must remain clear at all times. -
Code Administration & Safety
NEC 110.26(A)(2) requires a minimum width of working space. For equipment rated 0–2000 V, what is the minimum width of the working space?
Correct — A. NEC 110.26(A)(2) specifies that working space width shall be at least 30 inches, or the width of the equipment, whichever is greater, measured from left to right in front of the equipment. -
Code Administration & Safety
A 480 V switchboard is installed facing a concrete wall with grounded metal parts on the wall (Condition 2). Per NEC Table 110.26(A)(1), what minimum working space depth is required?
Correct — B. Under NEC Table 110.26(A)(1), for voltages 151–600 V phase-to-ground (which includes 480 V), Condition 2 requires 4 feet (48 inches) of working space depth. Condition 2 exists when grounded parts are on one side and live parts on the other. -
Code Administration & Safety
What is the primary purpose of equipment grounding in an electrical system?
Correct — C. Equipment grounding creates a low-impedance path for fault current to flow back to the source, causing the overcurrent protective device to open quickly and clear the fault, protecting people and equipment. -
Code Administration & Safety
Bonding in electrical systems is defined by the NEC as:
Correct — D. NEC Article 100 defines bonding as the permanent joining of metal parts to create a conductive path. Bonding ensures that metal enclosures, raceways, and equipment are at the same potential, preventing dangerous voltage differences. -
Code Administration & Safety
At a separately derived system (e.g., a transformer secondary), where must the system bonding jumper be installed?
Correct — A. NEC 250.30(A)(1) requires the system bonding jumper for a separately derived system to be installed at the source (transformer) or at the first disconnecting means, but not at both. Installing it at both would create parallel paths for neutral current. -
Code Administration & Safety
GFCI protection is required by the NEC for 125 V, 15A and 20A receptacles in which of the following locations?
Correct — B. NEC 210.8 requires GFCI protection for receptacles in bathrooms, garages, outdoors, crawl spaces, unfinished basements, and kitchen countertop areas. GFCI detects ground-fault currents as small as 4–6 mA and quickly interrupts the circuit. -
Code Administration & Safety
According to NEC 210.8(B), GFCI protection is required for 125 V through 250 V, 15A and 20A receptacles in commercial and industrial occupancies in which area?
Correct — A. NEC 210.8(B) extends GFCI requirements in commercial/industrial settings to rooftops, outdoors, kitchens, bathrooms, crawl spaces, and similar damp or wet locations, regardless of voltage rating within 125–250 V range. -
Code Administration & Safety
NEC 210.8(D) requires GFCI protection for single-phase receptacles rated 250 V or less, 50A or less, installed in which location?
Correct — D. Starting with the 2020 NEC, 210.8(D) expanded GFCI requirements to cover single-phase, 250 V or less, 50A or less receptacles in the same locations already covered for 15/20A devices, including marinas, boat hoists, and rooftops. -
Code Administration & Safety
Per NEC 210.12, AFCI protection is required for all 120 V, 15A and 20A branch circuits supplying outlets or devices installed in which room types in dwelling units?
Correct — C. The 2017 and later NEC editions expanded AFCI requirements to cover all 15/20A, 120 V branch circuits in essentially all dwelling unit rooms. Previously, only bedrooms were required to have AFCI protection. -
Code Administration & Safety
When an AFCI circuit breaker is replaced in an existing panel that does not have a grounded (neutral) bus connection available at the breaker, NEC 210.12(D) permits using which alternative?
Correct — B. NEC 210.12(D) allows outlet branch-circuit type AFCI protection at the first outlet when replacing a breaker in an existing panel where the panelboard is not marked to accept AFCI breakers or lacks a neutral connection.
Master Electrician 2 sample questions
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Code Administration & Safety What is the primary purpose of an overcurrent protective device (OCPD) in an electrical circuit?
A. To open the circuit when current exceeds the conductor's ampacity, protecting wiring from overheating ✓
B. To regulate voltage to loads
C. To prevent power quality problems
D. To disconnect the neutral conductor first
Correct — A. OCPDs such as fuses and circuit breakers protect conductors from damage caused by excessive current. When current exceeds the conductor's rated ampacity, the OCPD opens the circuit before the insulation is damaged.
Grounding & Bonding What is the primary purpose of grounding an electrical system?
A. To improve power factor
B. To limit the voltage imposed by lightning, line surges, or unintentional contact with higher-voltage lines ✓
C. To reduce line losses
D. To balance phase currents
Correct — B. NEC 250.4(A)(1) states that grounding of electrical systems limits voltage from lightning, line surges, or accidental contact with higher-voltage lines, protecting equipment and personnel.
Service & Feeder Load Calculations What unit load (VA per square foot) does NEC Table 220.12 assign to a dwelling unit for general lighting purposes?
A. 3 VA/sq ft ✓
B. 2 VA/sq ft
C. 4 VA/sq ft
D. 5 VA/sq ft
Correct — A. NEC Table 220.12 specifies 3 VA per square foot for dwelling units. This base unit load covers general-purpose receptacle and lighting circuits.
Motors & Transformers What principle causes a conductor carrying current in a magnetic field to experience a mechanical force?
A. Motor action (Lorentz force) ✓
B. Lenz's law
C. Faraday's law of induction
D. Kirchhoff's voltage law
Correct — A. The Lorentz force (motor action) states that a current-carrying conductor in a magnetic field experiences a force proportional to the current, field strength, and conductor length. This is the fundamental principle behind all electric motors.
Overcurrent Protection Which fuse type is specifically designed to be time-delay (slow-blow) and is commonly used for motor branch-circuit protection?
A. Dual-element time-delay fuse ✓
B. Fast-acting cartridge fuse
C. One-time fuse
D. Current-limiting fuse
Correct — A. Dual-element (time-delay) fuses have two separate fusible elements: one for sustained overloads and one for short circuits. This characteristic makes them ideal for motor circuits where high inrush currents occur at startup.
Services & Distribution Service-entrance conductors that are installed outdoors and run from the service point to the service equipment must comply with which NEC article?
A. Article 230 ✓
B. Article 215
C. Article 225
D. Article 240
Correct — A. NEC Article 230 covers services, including service-entrance conductors installed outdoors from the utility service point to the service equipment. Article 215 covers feeders, and Article 225 covers outside branch circuits.
Theory & Advanced Calculations A circuit has a resistance of 20 Ω and a current of 3 A flowing through it. What is the voltage across the resistance?
A. 30 V
B. 40 V
C. 60 V ✓
D. 80 V
Correct — C. Ohm's Law: V = I × R = 3 A × 20 Ω = 60 V.
Wiring Methods & Materials Which wiring method consists of a metallic tube used to enclose and protect electrical conductors?
A. Rigid metal conduit (RMC) ✓
B. Armored cable (AC)
C. Metal-clad cable (MC)
D. Surface metal raceway
Correct — A. Rigid metal conduit (RMC) is a metallic tube (raceway) that houses conductors. It provides the highest mechanical protection among conduit types and is covered under NEC Article 344.
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Safe work practices and PPE
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