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Ohio Electrical Contractor Practice Test

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Free Ohio Electrical Contractor Practice Sample Questions & Answers

Question 1. A commercial building has a continuous load of 32 amperes and a noncontinuous load of 18 amperes on a 120/240-volt single-phase feeder. Assuming the conductors are sized at 125% of the continuous load plus 100% of the noncontinuous load, what minimum ampacity is required?

A. 50 amperes

B. 54 amperes

C. 58 amperes

D. 62 amperes

Correct Answer. C. 58 amperes

Explanation: The continuous portion of the load must be multiplied by 125%, while the noncontinuous portion is included at 100%. For the continuous load, 32 amperes × 1.25 equals 40 amperes. Adding the 18-ampere noncontinuous load produces a calculated load of 58 amperes. Therefore, the conductors need an ampacity of at least 58 amperes before applying any other applicable adjustment, correction, or equipment limitations. When selecting the actual conductor size, the contractor must consult the applicable NEC requirements and ampacity tables rather than simply choosing a conductor based on the calculated value alone.

Question 2. An electrical contractor is installing a feeder supplying a panelboard in a commercial building. The calculated load requires conductors rated for 75 amperes. Before selecting the conductor size, which factor should be verified in addition to the calculated load?

A. The color of the panelboard enclosure

B. The applicable conductor ampacity and termination limitations

C. The length of the thermostat cable

D. The manufacturer’s preferred conduit color

Correct Answer. B. The applicable conductor ampacity and termination limitations

Explanation: A calculated load does not by itself determine the final conductor size. The contractor must verify the conductor’s allowable ampacity and determine whether the equipment terminals are suitable for the conductor temperature rating being used. The applicable NEC rules can also require adjustment or correction for conditions such as ambient temperature or the number of current-carrying conductors. Equipment ratings and installation conditions must therefore be considered before making the final selection. Simply choosing a conductor whose printed ampacity appears adequate can result in an improper installation if termination ratings, correction factors, or other applicable requirements have been overlooked.

Question 3. A three-phase motor repeatedly trips its overload protection during normal operation. The motor is mechanically free to rotate, and the supply voltage is within the manufacturer’s specified range. Which measurement would be most useful for determining whether the motor is overloaded?

A. Current drawn by each phase

B. Resistance of the building grounding electrode

C. Temperature of the panelboard door

D. Voltage at an unrelated lighting circuit

Correct Answer. A. Current drawn by each phase

Explanation: Measuring current on each phase provides important information when diagnosing a three-phase motor that repeatedly trips its overload protection. The readings can be compared with the motor’s nameplate full-load current and with one another. Excessive or significantly unbalanced current may indicate an overloaded motor, mechanical problem, phase imbalance, connection issue, or another operating condition requiring investigation. Voltage should also be verified, but the question already establishes that supply voltage is within the specified range. The technician should not simply increase the overload setting to prevent nuisance trips because doing so could remove necessary motor protection and create an unsafe operating condition.

Question 4. A transformer is installed to supply a 120-volt control circuit from a higher-voltage source. After installation, the secondary circuit measures substantially less than the expected voltage under load. Which condition should be investigated first?

A. Primary and secondary connections and transformer rating

B. Lighting fixture color temperature

C. Conduit exterior finish

D. Ground rod length only

Correct Answer. A. Primary and secondary connections and transformer rating

Explanation: A transformer that produces substantially lower-than-expected secondary voltage should first be evaluated for correct connections, voltage ratings, and loading. The contractor should verify that the primary is connected to the correct voltage and that the secondary is wired according to the manufacturer’s diagram. Excessive secondary loading can also produce voltage drop, so the connected load should be compared with the transformer’s rated capacity. Incorrect tap selection, wiring configuration, or an improperly sized transformer may also affect the output. Grounding requirements remain important, but they would not normally be the first explanation for a significantly low secondary voltage under load.

Question 5. An electrical contractor is installing conductors in a raceway containing several other current-carrying conductors. The ambient temperature is also higher than the temperature used for the basic ampacity table. What should be considered when determining conductor ampacity?

A. Only the conductor insulation color

B. Adjustment and correction factors

C. Only the raceway manufacturer’s logo

D. The number of wall switches in the building

Correct Answer. B. Adjustment and correction factors

Explanation: Conductor ampacity can be affected by installation conditions. When multiple current-carrying conductors occupy the same raceway, the resulting heat accumulation may require an adjustment to the allowable ampacity. Elevated ambient temperature can also require a correction factor based on the conductor insulation rating and applicable NEC requirements. These factors should be applied using the appropriate tables and rules before the final conductor size is selected. The contractor should evaluate the actual installation conditions rather than relying only on the basic ampacity listed in a table. Correctly applying adjustment and correction factors helps prevent excessive conductor temperature during normal operation.

Question 6. A branch circuit supplies several receptacles in a commercial area. One receptacle is located where personnel may be exposed to water. Which consideration becomes especially important when determining the required protection?

A. Ground-fault protection requirements

B. Increasing the receptacle’s decorative finish

C. Reducing the circuit conductor size

D. Removing the equipment grounding conductor

Correct Answer. A. Ground-fault protection requirements

Explanation: Locations where electrical equipment may come into contact with water can present an increased shock hazard. Depending on the specific location, equipment, occupancy, and installation conditions, the NEC may require ground-fault circuit-interrupter protection or other protective measures. The contractor should identify the exact installation conditions and consult the applicable NEC provisions rather than assuming that ordinary receptacle requirements apply. Ground-fault protection is intended to reduce the risk associated with unintended current paths to ground. The correct protective device and installation method should be selected according to the current code requirements and the specific characteristics of the location.

Question 7. A panelboard is being installed in a location where several branch circuits will terminate. During the layout, the contractor discovers that the proposed location does not provide adequate working space in front of the equipment. What is the appropriate response?

A. Install the panelboard because the circuits are short

B. Reduce the panelboard voltage

C. Correct the location or layout before completing the installation

D. Install a larger cover to compensate

Correct Answer. C. Correct the location or layout before completing the installation

Explanation: Electrical equipment must have appropriate working space so that inspection, operation, maintenance, and servicing can be performed safely. If the proposed panelboard location does not provide the required working clearance, the installation should be corrected before the equipment is permanently installed. Moving the panelboard, modifying the surrounding layout, or selecting another compliant location may be necessary. Changing the voltage, installing a different cover, or relying on short circuit lengths does not eliminate the working-space requirement. The contractor should verify the applicable NEC provisions for the specific equipment and location before proceeding with the installation.

Question 8. A contractor is installing a raceway system containing conductors for a feeder. The raceway route includes several bends between accessible points. Before pulling the conductors, what should be verified?

A. That the raceway installation complies with applicable bending and pulling requirements

B. That all conductors have identical insulation colors

C. That the panelboard is painted before wiring

D. That the feeder operates without an equipment grounding conductor

Correct Answer. A. That the raceway installation complies with applicable bending and pulling requirements

Explanation: Raceways must be installed so that conductors can be safely installed, pulled, and maintained without exceeding applicable mechanical limitations. Excessive bends between accessible points can make conductor installation difficult and may violate NEC requirements. The contractor should verify the permitted number of bends, accessibility of pull points, raceway size, conductor fill, and other applicable installation requirements before pulling the conductors. Proper planning is especially important for larger feeders because conductors can be difficult to pull and may be damaged by excessive pulling tension or sharp bends. Raceways should therefore be evaluated before the wiring installation begins.

Question 9. A generator is being connected to a building’s electrical system to provide standby power during utility outages. Which issue requires particular attention when designing the connection?

A. Transfer equipment and prevention of unintended utility interconnection

B. Decorative lighting temperature

C. Receptacle faceplate color

D. Interior wall paint thickness

Correct Answer. A. Transfer equipment and prevention of unintended utility interconnection

Explanation: A standby generator connection must be designed so that the generator and utility supply are controlled safely. Transfer equipment is used to manage the transition between normal and alternate power sources and, where required, prevent the generator from unintentionally energizing utility conductors. The contractor must also consider grounding, bonding, overcurrent protection, conductor sizing, and the generator manufacturer’s requirements. Simply connecting a generator to existing building wiring without appropriate transfer equipment can create a serious hazard for utility personnel and building occupants. The exact installation must follow the applicable NEC provisions and the requirements associated with the specific generator and transfer equipment.

Question 10. During troubleshooting, a technician finds that a control relay does not energize when the equipment receives a start command. The control transformer has the correct secondary voltage. What should be checked next?

A. The control circuit path and relay coil voltage

B. The building’s exterior lighting color

C. The refrigerant charge of unrelated equipment

D. The grounding electrode location only

Correct Answer. A. The control circuit path and relay coil voltage

Explanation: If the control transformer is producing the correct secondary voltage but the relay does not energize, the next step is to trace the control circuit and determine whether the relay coil is receiving the required voltage when the start command is present. Open switches, safety controls, wiring faults, loose connections, failed contacts, or a defective control component can interrupt the circuit. The technician should use the equipment wiring diagram and appropriate electrical measurements to identify where the control signal is being lost. Replacing the relay immediately may overlook the actual fault if the relay is not receiving the proper control voltage.

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Description

Preparing for the Ohio Electrical Contractor Exam means being able to apply electrical knowledge—not simply remember definitions.

The Ohio Electrical Contractor Practice Test gives you a practical way to review contractor-level electrical concepts, work through code-related situations, practice calculations, and test your understanding before the official licensing examination.

The questions are designed around situations an electrical contractor may encounter when planning, installing, inspecting, troubleshooting, and maintaining electrical systems.

Put Your Electrical Knowledge to the Test

Electrical licensing questions can require you to connect several concepts before selecting an answer. A question about a feeder, for example, may involve conductor ampacity, overcurrent protection, load requirements, and installation conditions.

This practice test helps you work through that type of reasoning with questions covering:

  • Electrical theory and calculations
  • NEC concepts and code application
  • Services and service equipment
  • Feeders and branch circuits
  • Conductors and cables
  • Raceway systems
  • Boxes and panelboards
  • Grounding and bonding
  • Transformers and electrical equipment
  • Motors and generators
  • Control devices
  • Utilization equipment
  • Special occupancies and equipment
  • Electrical troubleshooting
  • Installation and safety practices

Cover the Major Ohio Electrical Exam Areas

The official Ohio Electrical Contractor examination covers several distinct subject areas, including general electrical knowledge, transformers and equipment, service feeders and branch circuits, raceways and boxes, conductors and cables, control devices, motors and generators, utilization equipment, and special occupancies and equipment.

That means effective preparation needs to extend beyond basic wiring knowledge.

Use the practice questions to move between different electrical topics and discover which areas you understand well and which ones require another review.

Get Comfortable With NEC-Based Questions

Knowing electrical theory is important, but contractor licensing preparation also requires familiarity with the National Electrical Code.

Practice questions can help you become more comfortable identifying the information you need from your reference material, including requirements involving:

  • Ampacity
  • Overcurrent protection
  • Grounding and bonding
  • Services
  • Feeders
  • Branch circuits
  • Wiring methods
  • Raceways
  • Boxes
  • Conductors
  • Motors
  • Transformers
  • Special installations

The Ohio examination is open book, so learning how to efficiently locate and verify information in your permitted references is an important part of preparation. Current PSI guidance should be checked before the examination because permitted materials and testing procedures can change.

Practice Electrical Calculations

Some of the most challenging questions are not solved by memorizing a definition.

You may need to calculate or evaluate:

  • Electrical loads
  • Conductor ampacity
  • Feeder requirements
  • Branch-circuit loads
  • Motor loads
  • Voltage drop
  • Transformer relationships
  • Overcurrent protection
  • Service requirements

Working through calculations repeatedly can make it easier to recognize the information that matters and avoid common mistakes when several numbers appear in the same question.

Review Real Installation Situations

Electrical contractors have to make decisions based on the actual conditions of an installation.

For example, a question may describe a commercial service upgrade, a motor installation, a panelboard, a transformer, a grounding arrangement, or equipment installed in a special location.

Instead of treating every question as a memorization exercise, use the scenario to identify:

  1. What electrical condition is being described?
  2. What requirement applies?
  3. What information needs to be verified?
  4. Which answer satisfies the situation?
  5. Why are the other choices incorrect?

This approach helps develop the kind of reasoning needed for contractor-level questions.

Strengthen Service, Feeder, and Branch Circuit Knowledge

Service, feeder, and branch-circuit requirements represent an important part of electrical contractor preparation.

Review questions involving service sizing, load calculations, conductors, disconnecting means, overcurrent protection, feeder installations, branch circuits, and distribution equipment.

Understanding how these parts of an electrical system relate to one another can help you approach complicated questions more confidently.

Study Motors, Generators, and Transformers

Electrical contractor work often involves equipment that requires specialized knowledge.

The practice test includes questions related to motors, generators, transformers, control equipment, and associated electrical applications.

Pay attention to operating conditions, protection requirements, conductor selection, control circuits, and equipment connections. When reviewing an incorrect answer, return to the relevant section of your reference material instead of simply memorizing the correct option.

Don’t Overlook Grounding and Bonding

Grounding and bonding are separate concepts, and questions may test whether you understand their different purposes within an electrical system.

Use practice questions to review grounding and bonding requirements, equipment grounding, system connections, and situations where proper electrical continuity and fault-current paths are important.

When studying these topics, focus on understanding the purpose behind the requirement. That makes it easier to recognize the correct application when the wording of a question changes.

Prepare for Special Electrical Conditions

Not every electrical installation has the same requirements.

Special occupancies and equipment can introduce additional considerations involving the environment, equipment type, installation method, and applicable electrical requirements.

The official examination content includes special occupancies and equipment as a separate subject area, making it an important part of a well-rounded preparation plan.

Review these questions carefully and use your current permitted references to verify the applicable requirements.

Use Practice Results to Guide Your Study

Your practice score is useful, but the questions you miss can be even more valuable.

After each study session, identify the subjects where you made repeated mistakes. You may discover that your difficulty is not with electrical theory itself but with a particular NEC topic, calculation, installation method, or terminology.

Keep track of those areas and revisit them before moving on.

A simple cycle works well:

Practice → Review → Check the reference → Correct the mistake → Practice again

This gives your study sessions a clear purpose instead of simply completing question after question.

Who Is This Ohio Electrical Contractor Practice Test For?

This resource can support preparation for:

  • Ohio electrical contractor licensing candidates
  • Experienced electricians
  • Electrical technicians
  • Journeyman electricians
  • Electrical apprentices
  • Trade school students
  • Contractors reviewing NEC requirements
  • Electrical professionals refreshing their technical knowledge

It can be particularly useful for candidates who want additional practice applying electrical concepts to contractor-level situations.

Prepare for the Official Examination

The Ohio Electrical Contractor trade examination is administered through PSI. Current examination information lists 100 scored questions, a four-hour time limit, and a 70% passing requirement, with additional pretest questions that are not scored. The examination is open book. Candidates should confirm the latest PSI bulletin before testing for the most current rules, reference materials, and procedures.

Use this practice test as a preparation tool alongside the official references and licensing information rather than as a substitute for them.

Start Practicing With Purpose

Strong exam preparation comes from understanding the material well enough to apply it when the question is presented in an unfamiliar way.

Work through the Ohio Electrical Contractor Practice Test, review the explanations, return to your reference materials when necessary, and keep track of the subjects that require additional attention.

The more comfortable you become with electrical calculations, NEC navigation, installation requirements, and contractor-level scenarios, the better prepared you can be for the official examination.

Ready to Start?

Put your electrical knowledge to work with focused practice questions covering the major areas of Ohio Electrical Contractor exam preparation.

Practice consistently, review your mistakes, and build the confidence to approach your licensing examination prepared.

Ready to Pass Your Exam?

You've reviewed the sample questions. Get instant access to the complete practice test with detailed explanations and prepare with confidence.

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FAQs

1. What is the Ohio Electrical Contractor Exam?
The Ohio Electrical Contractor Exam is a trade examination used as part of Ohio's electrical contractor licensing process. It assesses knowledge of electrical installations, code requirements, equipment, calculations, and other areas relevant to electrical contracting. Candidates should review the current Ohio licensing requirements and PSI examination information before registering.
How many questions are on the Ohio Electrical Contractor Exam?
The Ohio Electrical Contractor trade examination currently includes 100 scored questions and has a four-hour time limit. PSI may also include additional pretest questions that do not count toward the final score. Because examination procedures can be updated, candidates should confirm the current PSI bulletin before their scheduled test.
What subjects are covered on the Ohio Electrical Contractor Exam?
The examination covers a broad range of electrical contractor topics, including general electrical knowledge, transformers and equipment, services, feeders, branch circuits, raceways, boxes and panelboards, conductors and cables, control devices, motors and generators, utilization equipment, and special occupancies and equipment.
Is the Ohio Electrical Contractor Exam open book?
Yes. The Ohio Electrical Contractor trade examination is administered as an open-book test. Candidates should become familiar with their permitted reference materials before exam day so they can locate electrical code information efficiently. Always check the latest PSI examination bulletin for the current list of approved references and testing rules.
How can I prepare for the Ohio Electrical Contractor Exam?
Start by reviewing the current examination content and approved reference materials. Then use practice questions to reinforce NEC concepts, electrical calculations, services, feeders, branch circuits, motors, transformers, controls, and other exam subjects. Reviewing explanations for incorrect answers can help identify knowledge gaps and show which topics need additional study before the official examination.

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