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Maryland (MD) Journeyperson Electrician Practice Exam
Question 1: Which symbol is commonly used to represent a switch in electrical schematics? A. S B. R C. L D. F Correct Answer: A Explanation: The letter “S” is conventionally used in schematics to denote a switch. Question 2: What is the unit of electrical power? A. Volt B. Ampere C. Watt D. Ohm Correct Answer: C Explanation: Power is measured in watts, which equals voltage multiplied by current. Question 3: What does Ohm’s Law state? A. V = I/R B. V = I × R C. V = I + R D. V = I – R Correct Answer: B Explanation: Ohm’s Law expresses the relationship between voltage (V), current (I), and resistance (R) as V = I × R. Question 4: A load calculation involves which of the following? A. Voltage drop only B. Power factor only C. Total wattage demand D. Resistance in series Correct Answer: C Explanation: Load calculations determine the total power demand, typically measured in watts. Question 5: In an electrical plan, a dashed line often indicates: A. A hidden component B. A load calculation C. Grounding D. Conduit Correct Answer: A Explanation: Dashed lines are typically used to represent items not visible or hidden in the installation.
Question 6: The symbol “∠” in electrical diagrams typically indicates: A. Phase angle B. Ground connection C. Conductor size D. Voltage drop Correct Answer: A Explanation: The “∠” symbol is used to show phase angles in AC circuit diagrams. Question 7: What is the primary purpose of a voltage drop calculation? A. To determine the conductor color B. To ensure proper voltage at the load C. To calculate energy consumption D. To size the transformer Correct Answer: B Explanation: Voltage drop calculations help ensure that the voltage at the load end remains within acceptable limits. Question 8: Electrical terminology “ampacity” refers to: A. Conductor’s resistance B. Conductor’s current-carrying capacity C. Conductor’s insulation type D. Voltage rating Correct Answer: B Explanation: Ampacity is the maximum current a conductor can carry safely. Question 9: The term “ground” in electrical plans is used to denote: A. Live conductor B. Neutral conductor C. Safety connection D. Load conductor Correct Answer: C Explanation: A ground provides a safety path to dissipate fault currents. Question 10: In calculating load, which of the following factors is most important? A. Color of wiring B. Ambient temperature C. Voltage drop D. All of the above Correct Answer: B Explanation: Ambient temperature can affect conductor ampacity and must be factored into load calculations.
Question 16: The term “separately derived system” refers to: A. A system with no connection to the supply B. A system derived from a transformer or generator C. A system with common grounding D. None of the above Correct Answer: B Explanation: A separately derived system is one that obtains power from a transformer or generator with no direct connection to the primary supply. Question 17: In electrical diagrams, a solid line typically represents: A. Hidden wiring B. Visible wiring C. Structural support D. Conduit Correct Answer: B Explanation: Solid lines normally show wiring or components that are visible and accessible. Question 18: Which symbol in a plan indicates a ground rod? A. Three horizontal lines B. A triangle C. A circle with lines D. A zigzag line Correct Answer: A Explanation: Three horizontal lines are often used to depict a ground rod in schematics. Question 19: For voltage drop calculations, which formula is commonly used? A. V = I × R B. V = P / I C. V = I² × R D. V = (I × L × R) / C Correct Answer: A Explanation: Voltage drop is calculated using Ohm’s Law, V = I × R, where I is current and R is resistance. Question 20: Which term best describes a diagram that shows the physical location of electrical components? A. Schematic B. Wiring diagram C. Layout plan D. Block diagram Correct Answer: C Explanation: A layout plan provides a physical representation of where components are installed.
Question 21: When reading an electrical plan, the term “elevations” refers to: A. Voltage levels B. Height dimensions C. Load factors D. Phase angles Correct Answer: B Explanation: Elevations indicate the vertical placement or height dimensions in a building. Question 22: Which calculation is essential for determining the proper conductor size? A. Conductor resistance B. Voltage drop C. Ambient temperature correction D. All of the above Correct Answer: D Explanation: All factors, including resistance, voltage drop, and ambient temperature, affect conductor sizing. Question 23: The term “ampere” is a measure of: A. Voltage B. Current C. Resistance D. Power Correct Answer: B Explanation: Amperes (amps) measure the rate of electrical current flow. Question 24: In AC circuits, “power factor” is the ratio of: A. Real power to apparent power B. Voltage to current C. Resistance to reactance D. Conductor size to length Correct Answer: A Explanation: Power factor is the ratio of actual (real) power used to the apparent power in the circuit. Question 25: What is the typical purpose of a one-line diagram? A. Detailed wiring B. Simplified representation C. Electrical load analysis D. Phase calculation Correct Answer: B Explanation: A one-line diagram simplifies the representation of the electrical system.
Explanation: A voltage drop calculation verifies that the voltage available at the load does not fall below acceptable levels. Section II. Electrical Services, Service Equipment, and Separately Derived Systems (Questions 31–60) Question 31: What is the primary function of service equipment in an electrical system? A. To connect the circuit to the grounding system B. To provide overcurrent protection and control the distribution of power C. To measure voltage D. To supply lighting Correct Answer: B Explanation: Service equipment protects and distributes power from the utility service to the building’s circuits. Question 32: Which component is typically the first point of disconnect for electrical services? A. Circuit breaker panel B. Main disconnect switch C. Distribution transformer D. Receptacle Correct Answer: B Explanation: The main disconnect switch is used to disconnect the electrical service at the point of entry. Question 33: A separately derived system is characterized by: A. Direct connection to the utility supply B. No connection to the grounding system C. Derivation from a transformer or generator D. Use only in residential installations Correct Answer: C Explanation: Such systems derive their power from a transformer or generator and are isolated from the primary supply. Question 34: What is the role of the service entrance conductor? A. To provide a path for fault current B. To connect the service equipment to the building’s interior C. To measure load D. Both A and B Correct Answer: D Explanation: The service entrance conductors carry power into the building and also provide a path for fault current to ensure safety.
Question 35: Service equipment ratings are based on which of the following? A. Maximum current load B. Ambient temperature C. Conductor size D. Length of cable run Correct Answer: A Explanation: The rating must accommodate the maximum current the system is expected to carry. Question 36: What does the term “busbar” refer to? A. A type of conductor used in service equipment for distributing power B. A protective device C. A grounding component D. A type of transformer Correct Answer: A Explanation: Busbars are metallic strips that distribute power within panels and switchgear. Question 37: Which of the following is a key consideration when selecting service equipment? A. Cost only B. Electrical load, environmental conditions, and safety requirements C. Color of the panel D. Manufacturer logo Correct Answer: B Explanation: Proper selection involves evaluating the load, installation environment, and safety standards. Question 38: In a separately derived system, the neutral is typically: A. Bonded to the grounding system at the service disconnect B. Isolated from the grounding system C. Connected directly to the transformer D. Not required Correct Answer: A Explanation: The neutral is bonded at the service equipment to ensure proper grounding. Question 39: The installation of service equipment must comply with: A. Local building codes only B. The National Electrical Code (NEC) and local codes C. Manufacturer’s recommendations only D. None of the above Correct Answer: B Explanation: Both NEC and local codes govern service equipment installations.
Question 45: When installing service equipment, it is essential to ensure proper: A. Grounding B. Bonding C. Overcurrent protection D. All of the above Correct Answer: D Explanation: Proper grounding, bonding, and protection are all vital for safety and equipment function. Question 46: Which device is used to interrupt current in the event of an overload? A. Fuse B. Circuit breaker C. Transformer D. Both A and B Correct Answer: D Explanation: Both fuses and circuit breakers serve as overcurrent protection devices. Question 47: A main bonding jumper is used to: A. Bond the neutral to the ground at the service entrance B. Connect the branch circuits C. Increase the load capacity D. Prevent short circuits Correct Answer: A Explanation: It ensures that the neutral and grounding systems are at the same electrical potential. Question 48: What is a key characteristic of a separately derived system? A. It must always be grounded at the transformer B. It cannot have any connection to earth ground C. It requires double insulation D. It does not require a neutral conductor Correct Answer: A Explanation: The secondary side of a transformer (a separately derived system) is typically bonded to ground. Question 49: In the context of electrical services, “demand factor” refers to: A. The maximum load B. The percentage of connected load expected to be used at one time C. The size of the service panel D. The type of wiring used Correct Answer: B Explanation: Demand factor accounts for the likelihood that not all connected loads will operate simultaneously.
Question 50: Which standard governs the installation of service equipment in the United States? A. NFPA 70 B. IEEE 1584 C. ANSI C84. D. UL 1741 Correct Answer: A Explanation: NFPA 70, also known as the NEC, is the primary code for electrical installations. Question 51: The service disconnect must be located within ______ feet of the point of entrance. A. 5 B. 10 C. 25 D. 50 Correct Answer: B Explanation: NEC typically requires the disconnect to be within 10 feet of the service entrance for safety and accessibility. Question 52: What does “bonding” in electrical systems ensure? A. Equalization of electrical potential B. Increase in voltage C. Conductor color matching D. Voltage drop compensation Correct Answer: A Explanation: Bonding ensures all metallic parts are at the same potential, reducing shock hazards. Question 53: The rating of a service disconnect switch is typically expressed in: A. Amperes B. Volts C. Watts D. Ohms Correct Answer: A Explanation: The rating is given in amperes to indicate the maximum current the switch can safely interrupt. Question 54: Which of the following is most important in the design of electrical services? A. Aesthetic appearance B. Safety and proper distribution of power C. Material cost only D. Ease of installation Correct Answer: B Explanation: The design must prioritize safety and ensure reliable power distribution.
A. Isolated B. Bonded to the grounding system C. Connected to the primary neutral D. Not used Correct Answer: B Explanation: Bonding the neutral on the secondary side ensures proper grounding and safety. Section III. Electrical Feeders (Questions 61–80) Question 61: What is the primary function of an electrical feeder? A. To distribute power from the service equipment to branch circuits B. To ground the electrical system C. To measure load D. To connect lighting circuits Correct Answer: A Explanation: Feeders transport power from the service equipment to various subpanels or branch circuits. Question 62: Feeder sizing calculations are primarily based on: A. Ambient temperature B. Total connected load C. Conductor color D. Number of outlets Correct Answer: B Explanation: The feeder must be sized to safely carry the sum of the connected loads. Question 63: Which of the following is used to protect feeders from overcurrent? A. Fuses B. Circuit breakers C. Both A and B D. Receptacles Correct Answer: C Explanation: Overcurrent protection for feeders is provided by fuses or circuit breakers. Question 64: In feeder calculations, what is the purpose of applying a demand factor? A. To increase conductor size B. To account for the diversity of load C. To lower voltage drop D. To determine conductor color Correct Answer: B
Explanation: Demand factors adjust the total connected load to a realistic level based on usage diversity. Question 65: Feeder conductors should be selected based on: A. Ampacity B. Voltage drop C. Installation environment D. All of the above Correct Answer: D Explanation: All these factors influence the appropriate conductor selection for feeders. Question 66: The term “feeder” typically refers to: A. A branch circuit conductor B. A conductor supplying power to subpanels C. A grounding conductor D. A lighting circuit Correct Answer: B Explanation: Feeders supply power from the main panel to subpanels or distribution equipment. Question 67: What is the main consideration when determining the protection for a feeder? A. Load current B. Conductor material C. Conductor color D. Voltage rating Correct Answer: A Explanation: The overcurrent protection must be sized according to the expected load current. Question 68: When calculating feeder sizes, which of the following is essential? A. Total load amperage B. Conductor insulation type C. Number of branch circuits D. All of the above Correct Answer: A Explanation: The primary calculation is based on the total amperage load served by the feeder. Question 69: Feeder conductors must be sized to handle: A. Only continuous loads B. The sum of continuous and noncontinuous loads C. Only noncontinuous loads D. None of the above Correct Answer: B Explanation: Both continuous and noncontinuous loads must be considered in the sizing.
A. To regulate voltage B. To prevent overcurrent damage C. To connect branch circuits D. To ground the system Correct Answer: B Explanation: Protection devices are used to interrupt excessive currents that could damage the feeder. Question 76: Which type of circuit breaker is commonly used for feeder protection? A. Thermal-magnetic B. Hydraulic C. Manual reset D. Digital Correct Answer: A Explanation: Thermal-magnetic breakers are common for feeder protection due to their reliable overcurrent response. Question 77: Feeder conductor calculations should consider which of the following? A. Conductor resistance B. Conductor length C. Operating temperature D. All of the above Correct Answer: D Explanation: All these factors influence the voltage drop and safe current-carrying capacity. Question 78: The term “feeder load” refers to: A. The load on a branch circuit B. The load served by the feeder C. The voltage drop in the feeder D. The overcurrent protection rating Correct Answer: B Explanation: Feeder load is the total load that the feeder must safely supply. Question 79: For feeders, which factor is directly related to conductor size selection? A. Current carrying capacity B. Conduit color C. Installation method D. Both A and C Correct Answer: D Explanation: Conductor size is chosen based on its ampacity and installation conditions. Question 80: Which method is most commonly used to calculate voltage drop in feeders? A. Ohm’s Law
B. Kirchhoff’s Voltage Law C. Watt’s Law D. Both A and B Correct Answer: D Explanation: Both Ohm’s Law and Kirchhoff’s Voltage Law can be applied to determine voltage drop in feeders. Section IV. Branch Circuit Calculations and Conductors (Questions 81–110) Question 81: The primary purpose of branch circuit calculations is to: A. Determine conductor size B. Select appropriate devices C. Balance loads D. All of the above Correct Answer: D Explanation: Calculations ensure that conductor sizing, device selection, and load distribution are all appropriately addressed. Question 82: When sizing a branch circuit, which factor is most important? A. Total load B. Voltage drop C. Conductor insulation D. Circuit length Correct Answer: A Explanation: The overall load (in amperes or watts) is the key factor in determining circuit sizing. Question 83: The term “branch circuit” refers to: A. Conductors supplying individual devices B. Conductors supplying power from the service equipment C. Grounding conductors only D. Conduit systems Correct Answer: A Explanation: Branch circuits deliver power from the panel to individual outlets and devices. Question 84: In branch circuit calculations, what is the typical percentage used for continuous loads? A. 50% B. 75% C. 125% D. 150% Correct Answer: C
Correct Answer: A Explanation: A multi-wire branch circuit uses a common neutral for two circuits. Question 90: When selecting conductors for branch circuits, one must consider: A. Ambient temperature B. Conductor insulation type C. Conduit fill D. All of the above Correct Answer: D Explanation: All these factors influence conductor performance and must be accounted for. Question 91: In branch circuit calculations, which standard is used to determine conductor sizing? A. NEC tables B. IEEE standards C. Local codes D. Manufacturer recommendations Correct Answer: A Explanation: NEC tables provide the ampacity ratings and guidelines for conductor sizing. Question 92: The purpose of a voltage drop calculation in branch circuits is to: A. Ensure proper operation of equipment B. Increase conductor size unnecessarily C. Adjust breaker ratings D. None of the above Correct Answer: A Explanation: Calculating voltage drop ensures that devices receive adequate voltage for proper function. Question 93: Which conductor is typically used for branch circuit wiring in residential installations? A. THHN B. XHHW C. UF-B D. All of the above Correct Answer: D Explanation: All these conductor types can be used, depending on installation conditions (e.g., indoor, outdoor, wet locations). Question 94: When calculating branch circuit loads, which of the following is included? A. Lighting loads B. Receptacle loads C. Fixed appliances D. All of the above
Correct Answer: D Explanation: All connected loads must be included in branch circuit load calculations. Question 95: What is the purpose of derating conductors in branch circuits? A. To account for high ambient temperatures B. To increase conductor size C. To reduce voltage drop D. To improve insulation Correct Answer: A Explanation: Derating adjusts the allowable current based on conditions like higher ambient temperatures. Question 96: Which calculation helps determine the proper overcurrent protection for branch circuits? A. Load calculation B. Voltage drop C. Phase balance D. Conductor resistance Correct Answer: A Explanation: The load calculation helps determine the appropriate rating for protective devices. Question 97: The term “circuit loading” refers to: A. The total wattage of devices B. The current draw on a circuit C. The voltage drop D. The conductor size Correct Answer: B Explanation: Circuit loading is the current that flows through the circuit under normal operating conditions. Question 98: When installing branch circuits, it is essential to ensure that: A. Conductors are properly insulated B. Overcurrent protection is correctly rated C. Voltage drop is within acceptable limits D. All of the above Correct Answer: D Explanation: Safe branch circuit design considers all these aspects. Question 99: The use of receptacle circuits is primarily to: A. Provide lighting B. Supply power to outlets C. Control motors D. Manage feeders
