Licensed Electrical Contractor Cheat Sheet 2026

The 30 highest-yield Licensed Electrical Contractor facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. According to NEC 250.122, how is the minimum size of an equipment grounding conductor determined for a branch circuit? → By the rating of the overcurrent device protecting the circuit
2. What is the frequency of standard US residential AC power? → 60 Hz
3. According to NEC Article 250, the main purpose of equipment grounding conductors (EGC) is to: → Provide a low-impedance fault current path to facilitate overcurrent device operation
4. Per NEC 230.71(A), what is the maximum number of service disconnecting means permitted for a single service? → 6 disconnects
5. When should you replace a circuit breaker? → When they fail to reset or show damage.
6. When must a licensed electrical contractor provide Safety Data Sheets (SDS) to employees under the OSHA Hazard Communication Standard? → SDS must be readily accessible to employees during their work shift
7. Which document legally transfers ownership of a completed construction project from the contractor to the owner? → Certificate of Substantial Completion
8. Which of the following best defines a 'Readily Accessible' location according to NEC Article 100? → Capable of being reached quickly without climbing over or removing obstacles.
9. What is the primary purpose of a mechanics lien in the electrical contracting business? → To secure payment for labor and materials provided on a construction project
10. Which method of accounting recognizes revenue when it is earned and expenses when they are incurred, regardless of when cash is received or paid? → Accrual basis accounting
11. Which NFPA standard is commonly known as the National Electrical Safety Code (NESC) and covers utility installations? → NFPA 70 does not cover utilities; the NESC is IEEE C2
12. Which type of electrical current periodically reverses direction? → Alternating current (AC)
13. Two 40-microfarad capacitors are connected in series. What is the total capacitance of the combination? → 20 µF
14. What is the maximum penalty per violation that OSHA can impose on an electrical contractor for a willful safety violation as of current federal guidelines? → $161,323
15. What should be used to protect circuits from overloads? → Circuit breakers or fuses.
16. What is the total impedance of a series RLC circuit with R = 30 ohms, XL = 50 ohms, and XC = 10 ohms? → 50 ohms
17. For a parallel conductor installation using two sets of 500 kcmil conductors per phase, what is the NEC requirement for conductor arrangement? → Each phase must have the same length, type, and termination method
18. Which type of fire extinguisher is appropriate for use on an energized electrical fire? → Class C
19. The NEC requires GFCI protection for 125V, 15- and 20-amp receptacles in: → Bathrooms, kitchens within 6 feet of sink, and outdoors
20. Which wiring method is required when installing conductors in a corrosive chemical storage area? → Rigid nonmetallic conduit (PVC)
21. What does the term 'scope of work' define in an electrical contracting agreement? → The specific tasks, deliverables, and boundaries of the contracted work
22. A young worker (under 18) hired by an electrical contractor may be restricted from certain tasks under which federal law? → The Fair Labor Standards Act (FLSA)
23. Under NEC 210.52, GFCI protection is required for all receptacles within how many feet of the outside edge of a bathroom sink? → 6 feet
24. What phenomenon occurs when the supply frequency matches a circuit's natural resonant frequency? → Impedance is minimized and current is maximized (series resonance)
25. What is the minimum rating required for any branch circuit that supplies two or more outlets or receptacles per NEC 210.3? → 15 amperes
26. What is the purpose of a transformer in an electrical circuit? → To change the voltage level in an AC circuit.
27. When troubleshooting a motor that hums but does not start, which component should be checked first? → Start capacitor
28. Under NEC 110.26, the minimum required working clearance in front of electrical equipment operating at 120V to ground in a Condition 1 environment is: → 3 feet
29. What does NEC 110.14 primarily address? → Electrical connections and terminals
30. What is the primary purpose of equipment bonding jumpers in an electrical system? → To ensure electrical continuity and conductivity between metal parts