South Carolina - NASCLA-Accredited Trade Examination for Residential Electrical Contractor Practice Exam
Free Practice Exam
Test your knowledge with 10 questions from our pool of 20 free questions.
- 10 questions per attempt
- 30 minute time limit
- Unlimited attempts
- A new mix each time
- Instant results
Full Practice Exam
Complete exam simulation matching the real PSI test format.
- 100 questions (same as real exam)
- 270 minute time limit
- 10 topic areas covered
- 495 questions in pool
- Detailed explanations
Texts preferred · 9am–9pm Central
South Carolina - NASCLA-Accredited Trade for Residential Electrical Contractor Practice Exam Guide
What's on the exam
Questions per topic, out of 100This practice exam follows the official content outline for the South Carolina - NASCLA-Accredited Trade for Residential Electrical Contractor exam: Theory, Personal Jobsite Safety (OSHA, NFPA 70E), Project Design, Estimating, and Measurement, Grounding and Bonding, Special System and Special Equipment Installations, Tools and Equipment, Circuit Protection and Installation, Wiring Methods and Practices, Equipment for General Use, Energy Efficiency/Management.
- Free practice exam: 10 questions per attempt, retake as often as you like.
- Full practice exam: 100 questions on a 270 minutes clock, a new draw from our bank every attempt.
Theory 9 items
Our study plan for this topic: Ohm's Law and the formula wheel (E, I, R, P relationships); Series circuit characteristics and calculations; Parallel circuit characteristics and calculations; Combination (series-parallel) circuit calculations; Alternating current fundamentals (sine wave, frequency, RMS and peak values, phase relationships); Inductance, capacitance, and reactance (XL, XC, impedance); Power factor, true power, and apparent power (kW, kVA, KVAR); Electrical formulas for amperes, horsepower, kilowatts, and kVA (single-phase and three-phase).
Personal Jobsite Safety (OSHA, NFPA 70E) 8 items
Our study plan for this topic: Electrical hazards: shock, electrocution, arc flash, and arc blast; Lockout/tagout procedures and establishing an electrically safe work condition; Arc flash risk assessment and shock protection boundaries (limited and restricted approach); Personal protective equipment (PPE) selection and arc flash PPE categories; Arc flash equipment labels and energized electrical work permits; OSHA employer and employee safety responsibilities and electrical safety programs; Fall protection systems and requirements (guardrails, personal fall arrest, safety nets); Ladder and scaffold safety requirements.
Project Design, Estimating, and Measurement 8 items
Our study plan for this topic: Branch-circuit, feeder, and service load calculations (NEC Article 220); Demand factors for dwelling unit loads (lighting, appliances, dryers, cooking equipment); Bidding and estimating process (quantity take-off, labor, materials, overhead, markup); Contract types, provisions, and change order management; Project scheduling methods (calendar, bar chart, critical path method); Applied math and measurement conversions (fractions, decimals, area, volume, metric/U.S. units); Reading and interpreting electrical symbols and wiring diagrams.
Grounding and Bonding 14 items
Our study plan for this topic: Grounding electrode system — types and installation requirements (rod, pipe, plate, concrete-encased, ground ring, water pipe); Grounding electrode conductor sizing and installation (NEC Table 250.66); Equipment grounding conductor types, sizing, and identification (NEC Table 250.122); Main bonding jumper and system bonding jumper — purpose, material, and sizing (NEC Table 250.102(C)(1)); Service equipment bonding methods and supply-side bonding jumper requirements; Grounding and bonding of metal water piping, gas piping, and structural metal; Grounded conductor identification, use, and terminal marking (Article 200); Equipment grounding conductor connections at boxes, receptacles, and service equipment.
Special System and Special Equipment Installations 7 items
Our study plan for this topic: Swimming pool, spa, and hot tub electrical installations (NEC Article 680 / IRC Chapter 42); Fire alarm system wiring and circuit requirements (NEC Article 760 / NFPA 72); Solar photovoltaic (PV) system installation requirements (NEC Article 690); Mobile homes, manufactured homes, and mobile home park electrical installations (NEC Article 550); Recreational vehicle and RV park electrical installations (NEC Article 551); Electric vehicle power transfer system (EVSE) installation requirements (NEC Article 625); Temporary electrical installations (NEC Article 590); Optional standby systems, portable and standby generators, and transfer equipment for dwellings (NEC Article 702).
Tools and Equipment 7 items
Our study plan for this topic: Conduit bending techniques (90° bends, offset bends, back-to-back bends, saddle bends); Hand bender and Chicago-type bender operation and calculations; Selecting and using digital multimeters (DMMs) for voltage, resistance, and current measurement; Clamp-on ammeter selection, testing, and use; Non-contact voltage tester selection, testing, and use; Test instrument safety categories (CAT I–CAT IV overvoltage ratings) and inspection requirements; Safe use and guarding requirements for hand and power tools (OSHA 1926 Subpart I); Portable electric tool and equipment maintenance requirements (NFPA 70E Article 245).
Circuit Protection and Installation 16 items
Our study plan for this topic: GFCI protection requirements by location in dwelling units; AFCI protection requirements and means of compliance; Overcurrent protective device types, ratings, and standard ampere sizes; Branch circuit conductor sizing and ampacity requirements; Service entrance installation requirements and disconnecting means; Surge-protective device (SPD) types, installation, and ratings; Working space clearances and equipment installation requirements.
Wiring Methods and Practices 17 items
Our study plan for this topic: Allowable wiring methods and their permitted applications by location and condition (NM, MC, AC, EMT, IMC, RMC, PVC, FMC, LFMC, ENT, LFNC, SE, UF, USE); Conductor types, insulation designations, temperature ratings, and application provisions (THHN, THWN, RHW, XHHW, TW, etc.); Conduit fill calculations — percent fill rules, number of conductors permitted, and conduit sizing procedures; Securing and supporting requirements for cables and raceways — fastening intervals, support spacing by wiring method; Protection of cables and raceways against physical damage — bored holes, notches, framing members, steel plates, and minimum distances; Box and enclosure requirements — box fill calculations, volume per conductor, pull box sizing, and wet/damp location requirements; Conductor ampacity, correction factors for ambient temperature, and adjustment factors for more than three current-carrying conductors; Voltage drop calculations for single-phase and three-phase circuits — formulas, conductor resistance values, and minimum cover requirements for underground wiring.
Equipment for General Use 13 items
Our study plan for this topic: Motor branch-circuit conductor sizing and ampacity requirements; Motor overload protection selection and ratings; Motor branch-circuit short-circuit and ground-fault protection; Motor controller and disconnecting means requirements; Motor nameplate markings and locked-rotor code letters; Transformer overcurrent protection, sizing, and calculations; Luminaire installation, support, and location requirements; Receptacle ratings, grounding types, and installation requirements.
Energy Efficiency/Management 1 item
Our study plan for this topic: Energy management system installation, load management, and load shedding restrictions (NEC Article 750); Lighting equipment efficacy requirements and interior/exterior lighting controls; Calculating operating cost of electrical appliances and energy savings from lamp replacement; Energy Management Systems; Changing Incandescent Lamp to Energy-Saving Lamp.
Sample 1 — Wiring Methods and Practices
Question: In an indoor wet location such as a dairy processing facility, what minimum airspace is required between an exposed wiring system and the wall or supporting surface?
- A. 1/2 in.
- B. 1/4 in.
- C. 3/4 in.
- D. 1/8 in.
Correct Answer: B
Per NEC 300.6(D), in indoor wet locations such as dairy processing facilities, laundries, and canneries, the entire wiring system installed exposed shall be mounted so that there is at least a 6 mm (1/4 in.) airspace between it and the wall or supporting surface.
Reference: NEC 2023 Section 300.6(D)
Sample 2 — Circuit Protection and Installation
Question: When a conductor with a 90°C insulation rating (such as THHN) is terminated on equipment rated for 75°C, which ampacity column must be used to determine the final ampacity of the conductor?
- A. The average of the 75°C and 90°C column values
- B. The 60°C column, since residential equipment defaults to that rating
- C. The 90°C column, since that is the conductor's insulation rating
- D. The 75°C column, matching the equipment termination temperature rating
Correct Answer: D
Per NEC 110.14(C), the ampacity of a conductor must be selected based on the lowest temperature rating of any connected termination, conductor, or device. When a 90°C conductor is connected to a 75°C terminal, its ampacity is limited to the 75°C column value. However, when applying correction or adjustment factors, the 90°C ampacity may be used as the starting point, provided the final derated value does not exceed the 75°C ampacity.
Reference: NEC 2023 Section 110.14(C)
Sample 3 — Grounding and Bonding
Question: For electrical systems required to be grounded, which of the following is a stated purpose of grounding the system?
- A. To reduce the resistance of the circuit conductors
- B. To increase the available fault current for equipment operation
- C. To eliminate the need for overcurrent protection devices
- D. To stabilize the voltage to earth during normal operation
Correct Answer: D
Per NEC 250.4(A)(1), electrical systems that are grounded shall be connected to earth in a manner that will limit the voltage imposed by lightning, line surges, or unintentional contact with higher-voltage lines and that will stabilize the voltage to earth during normal operation.
Reference: NEC 2023 Section 250.4(A)(1)
- Your results break the score down by outline topic.
- The real exam's passing score: 70 correct answers out of 100 scored questions.
- Keep practicing until you pass consistently, not just once.
- Answer what you know first and bookmark the rest. Our practice exams let you bookmark and come back.
- Work your bookmarks on the second pass.
- Real exam pace: about 2 minutes 42 seconds per question.
- After each attempt, look up every miss in your book.
| Questions | 100 questions |
| Time limit | 270 minutes |
| Passing score | 70 correct answers out of 100 scored questions |
| Books in the exam room | Open book |
| Exam fee | $116 |
- Results are given on screen immediately after the exam, with a performance summary for passers and a diagnostic report for those who do not pass.
- You get 3 attempts within a 12-month period, and after three failures you must wait twelve months from the last attempt to test again.
Source: Residential Builders and Residential Specialty Examinations Candidate Information Bulletin, Updated 10/9/2026. Check the bulletin before test day: fees and rules can change.